FLASH SONAR PROGRAM:  helping blind people learn to see

by

Daniel Kish, M.A., M.A., COMS, NOMC

Copyright 2009, April Revision

By

World Access for the Blind

 [This document incorporates materials from a document written by Daniel Kish and Hannah Bleier, M.A., COMS. Although this program in practice has been found quite successful, the documentation of this program is still under development. Please forgive the rough edges.]

 Before we begin, we'd like to present an excerpt from a letter submitted to a blind adult's listserve by a parent whose son received services from us. Among other things, this letter speaks to the ease and acceptance of using FlashSonar. This letter is presented in its entirety at: {{http://www.worldaccessfortheblind.org/common_questions_and_concerns/index.html#60697852}}

"... My youngest son, justin, totally blind, is five years old ... we introduced Justin to a white cane when he was 18 months old, as he was already becoming very physically active. Now ... he is very used to it and processes the information he gains from it very effectively. Justin is a very active, outgoing fellow who loves socializing and sports of any kind. ... We had already noticed Justin using what we thought was echolocation to some degree ... the work [Daniel] has done with Justin has had tremendous results. ... Walls are easy for Justin to hear. He has moved on to identify parked cars, store displays, other solid objects like newspaper boxes, bushes, and more all with the click of his tongue. ... if I ask Justin to go and find a ... solid object that doesn't make noise, he will click his tongue, and ... set off in that direction. As he nears it, he will actually pick up speed and become more confident ... He can then stop short of it ... The delight on his face when i tell him to reach out and see if he has found and he discovers he has is unparalleled. ... The other day my husband asked Justin to tell him when the type of fence changed along the street ... Clicking his tongue, Justin could tell him when the fence changed from a brick to a wrought iron barred fence ... As i mentioned, we had seen Justin using echolocation on his own as a toddler. ... I'm not sure how much Justin knew what he was doing, or how much further he would have went with it. I know that I have heard a lot of blind adults say that they use echolocation to some degree, to varying extents. But in Justin's case, with structured training his potential in this area is being drawn out and he is learning to use echolocation more effectively than he would have otherwise. ... We, like any parents, want the best for our son. We want him to be as independent and free as he can be. To give him that, we want him to have access to all the options, so that he knows what is possible and can make his own choices. Echolocation training is most definitely helping to accomplish that goal. ... 10 years ago it was unheard of to put a cane in the hand of a toddler. Our toddler is one little boy who has benefited hugely from being introduced to one at such a young age. How many people ten years ago, and even now for that matter, would have told me not to give my son a cane? Is the same thing true to some extent of echolocation? Or are we open-minded enough to explore the idea deeply enough to see if, just maybe, this is a relatively untapped area with tremendous potential? ... I strive to give my child access to all of the resources I can to help him become who he wants to be. This is one such resource. ... probably my greatest strength with my son is my ability to teach him social skills. I have a very strong interest in this area, and it shows in who Justin is becoming. He is extremely well spoken, ... very outgoing, confident, and well-liked by his friends and classmates. ... a tongue click ... is hardly noticeable. In fact, unless you were listening specifically for it, I don't know that you would notice it. Ok, well if you are blind you almost surely would, but I am commenting as a sighted person. it is hardly noticeable at all. ... the tongue click in no way resembles a blindism or mannerism. ... Today Justin does not exhibit any mannerisms ... here is something positive that it does do. It keeps the head up nicely, because when you click to scan your environment you lift your head up instead of hanging it down.... what does draw people's attention to my son is his cane, more than anything else. Since he first started using it at 18 months, people tend to watch us wherever we go. ... His cane by far draws more attention than a tongue click ever would. It is what it is, and that is the reality of it from our own experience. ... Tricia"

I. INTRODUCTORY COMMENTS:

      A. Vision and hearing are close cousins in that they both can process reflected waves of energy. Vision processes photons (waves of light) as they travel from their source, bounce off surfaces throughout the environment and enter the eyes. Similarly, the auditory system can process phonons (waves of sound) as they travel from their source, bounce off surfaces and enter the ears. Both systems can extract a great deal of information about the environment by interpreting the complex patterns of reflected energy that they receive. In the case of sound, these waves of reflected energy are called "echoes."

      To get these echoes, specialized sounds called echo or sonar signals are generally sent out. These signals travel forth, strike surfaces in the surrounding environment and return. The process is much like using a flashlight. Although sonar is much lower resolution than vi.n due to the use of much larger wavelengths, the listener can interpret information about surrounding surfaces that the returning echoes carry, much as a sighted creature interprets patterns of returning light. The echoes actually provide real, concrete images of space that we call auditory images, that bears a gross resemblance to the spatial characteristics of visual images.

      Blind humans can fill the darkness with dynamic images derived, not from light, but from sound. A blind traveler can perceive multi-dimensional information from distances of many dozens of meters depending on circumstances. Echoes make information available about the nature and arrangement of objects and environmental features such as overhangs, walls, doorways and recesses, poles, ascending curbs and steps, planter boxes, pedestrians, fire hydrants, parked or moving vehicles, trees and other foliage, and much more. Echoes can give detailed information about location (where objects are), dimension (how big they are and their general shape), and density (how solid it is). Location is generally broken down into distance from the observer, and direction (left/right, front/back, high/low). Dimension refers to the object's height (tall or short) and breadth (wide or narrow). Density refers to how solid or sparse, how reflective or absorbent an object is. Just by understanding the interrelationships of these qualities, much can be perceived about the nature of an object or multiple objects. For example, an object that is tall, narrow, and uniform from bottom to top may be recognized quickly as a pole. An object that is tall, narrow, and solid near the bottom while broadening and becoming more sparse near the top would be a tree. More specific characteristics, such as size, leafiness, or height of the branches can also be determined. Something that is tall, very broad, and solid registers as a wall or building, whereas something solid and broad, yet short in height, perhaps waist high, would register as a retaining wall. Something broad yet sparse in sound would register as a fence. Something short and fairly narrow, a little wider than a person, with a sparse, scattery sound might be a bush, whereas something with a sparse, scattery sound but broad might be a hedge or tightly packed row of bushes. Something that is broad and tall in the middle, yet shorter at either end may be identified as a parked car. The differentiation in the height and degree of slope at either end can identify the front from the back end; typically, the front will be lower, with a more gradual slope up to the roof. Distinguishing between types of vehicles is also possible. A pickup truck, for instance, is usually taller, with a hollow sound reflecting from its bed. An SUV is usually tall and boxy overall, with a distinctly blocky geometry at the rear. And finally, something that starts out close and very low, but recedes into the distance as it gets higher is a set of steps. More or less concentrated scanning may be necessary to make some of these determinations. But, by using this information, a scene can be analyzed and imaged, allowing the listener to establish orientation and direct movement within the scene. Natural scientists refer to this as scene analysis. As with the visual system, this process becomes unconscious.

      B. The term "FlashSonar" is generally used throughout this program, rather than the more conventional term "echolocation." This is because the conventional term echolocation has unfortunately come to represent and describe the more conventional use of echolocation, which is typically rudimentary and far short of its actual capacity and scope. Many are under the impression that the echolocation they teach or use represents the extent of its capacity, but we have found this to be untrue in almost every case. Others feel that only a select few can learn the skill to a heightened capacity, but we have found this, too, to be untrue. We have found notable success with most students of all ages and backgrounds including students with autism, hearing loss and cognitive impairments. We have also successfully taught very young toddlers. What is sometimes taught and often used is only preliminary to the more advanced degree, scope, and complexity of perception that echolocation can afford. Further, no systematic, comprehensive training programs have been documented to our knowledge that support and facilitate the development of this valuable way of seeing. For this reason we have coined the term "FlashSonar" to differentiate the strategic use of advanced, active sonar from the more commonly applied forms of echolocation. This was partly inspired by the fact that, in all of nature, humans are the only animals to our knowledge that tend to rely on more passive or incidental forms of echolocation. Active echolocation, which is about to be discussed, is believed to be the standard form of application throughout nature, and in almost all technical applications.

      C. This program is not yet complete. It is still evolving, but it provides a firm foundation in facilitating the perceptual adaptation process with regard to FlashSonar.

      D. This program is based only loosely on a method of sequenced skills development. As a developmental psychologist, I don't fully subscribe to the sequenced approach. While rough developmental milestones and sequences may exist, they are heavily dependent on personal, social, and environmental factors. This is particularly true for blind individuals whose developmental sequencing is even looser than that of the general population. This is especially true when considering that a much higher percentage of the blind population is faced with the challenge of additional involvements. Given this, we have found that the application of a sequenced skills curriculum often misses the mark. I would say that development and learning are only partly driven by developmental sequences that may be more or less hard wired, and also largely driven by what we may call "salience." We are driven to learn and grow by what is salient to our interest, survival, and attainment of resources. For example, children understand fractions long before they are formally taught the arithmetic operations as demonstrated by their awareness of equity when it comes to cutting pie and pizza. They often understand money long before they are able to do percents, and all of us understand time (base 12 or base 24) before we are even introduced to the concept of bases. Blind children are often observed to excel well beyond their sighted peers at certain skills, such as swimming, climbing, music, roughhousing, and auditory processing, and research has shown them to develop abstract language well ahead of "schedule," as these various skills may be more salient to their style of exploring and understanding the world. Thus, we have been unable to develop a step by step, sequenced curriculum that we feel properly supports the perceptual adaptation process. This program is based more on salience than sequence. The instructor should be warned not to try to impose this curriculum on a student in a sequenced, prescripted manner, but should first strive to understand the student's perceptual and environmental interaction style.

      The key above all, is to maintain a student's interest in the tasks, and motivation to learn. Some students may seem averse to self directed travel, but it is vital that this aversion be replaced by a desire to explore and discover, even if assisted to do so. Helping the student maintain interest and motivation is worth far more than the most carefully designed hierarchy of tasks. In our experience, once the student's interest is lost it doesn't much matter what we do.

      E. This program is in no way intended to constitute a complete set of activities or skills that may be learned. The activities included are selected to represent broadly the principal types of interactions that people may have with the environment. They are also intended to provide focused opportunities to practice developing certain specific skills. These activities must be adjusted or modified according to student need and environmental determinants. It will also be necessary to add other activities according to need. The sequence suggested here is only a very general guide, and will not apply to every student in all situations. In fact, it really should not be thought of as a "sequence." However, generally speaking, it is easier to learn to perceive one target before many targets, simple targets before complex targets, and targets from a stationary perspective before moving. Nonetheless, there are notable exceptions. Some students, for instance, can't make head or tales out of the simple panel exercises before they've been able to experience it walking around in the real environment.

      You can make a sonar exercise out of just about any activity. Many kids love to play around with a tetherball. We would have them find tetherball poles with the incentive that one of the poles had a tetherball. They loved it. Other times it was "take me to the things you like to play on." These might be monkey bars, swings, the slide, a merry-go-round, etc., that they were encouraged to find with FlashSonar. While it is often surprising what blind kids can do and learn, we were also surprised by what our students didn't know, like "how do you get to the jungle-gym from the slide." Blind kids who just follow the sighted kids all the time may not know. With one kid, I would pick him up and spin him around in a toy airplane to get him totally disoriented. He had a blast. Then we would practice finding the slide from where I set him down. He loved it!

      F. We have found FlashSonar training to be applicable to almost anyone who wants to learn, and who has opportunity for regular practice under challenging circumstances. The perceptual system is not necessarily tied to the communication or cognitive process, so many of these skills can be learned even when cognition or communication is impacted. With students who are low verbal or cognitively delayed, we use a more experiential approach, with less drill and less verbal explanation.

II. Perceptual development considerations:

      A. The ability to direct our interactions with the environment is connected to the perceptual imaging system. The brain creates images through the perceptual system to represent everything we experience. The quality of these images impacts how we interact with the environment. The brain uses perception to gather information which feeds comprehension, which further improves our interaction.

      Perception lies at the center of our ability to direct ourselves toward achievement. Other processes, such as comprehension, psychology, and mutual social engagement, are critical, but information supports the development and utility of all other neural mechanisms underlying self direction. Without information about the world, what is their to comprehend, who is their to engage socially and by what means, and with whom and how do we relate psychologically? We establish and execute intent by drawing meaning from what our senses register. The more information we can access, the more adaptive and more varied is our interaction with the world.

      accordingly humans have developed integrated, adaptive brain function that anticipates information through the perceptual process in two principal modes relative to movement - referencing and preview. Referencing refers to recognizing and discriminating elements around us which allows us to set a physical goal toward which movement can be directed, and to maintain orientation with respect to surrounding elements. Preview refers to awareness of elements and their layout in advance of our position. This allows us to direct our course efficiently, safely, and gracefully. Both these modes of gathering information can be divided into near, intermediate, and far.

      We use this information about what lies ahead and around us to govern interaction.  Without this information, the purposeful flow of movement is disrupted. We struggle to apply other processes to interact with the environment in a manner that is adaptive and mutually meaningful to self and others. Broadly speaking, this usually disrupts the development of grace and confidence to direct ourselves toward achievement.

      Neural development depends largely on self directed discovery based interaction with our environment. Directing our own interactions, rather than passively responding to others' directives, engages the nervous system most completely; it matures best by understanding its relationship to the world through self initiated, self directed exploration. A strong perceptual process helps develop strong intentional action.

      A robust operational image is rich in character derived from multiple data streams of sensory experience and ideas. When vision is compromised, the brain naturally works to maintain image integrity by optimizing perception and self directed discovery to heighten the quality of meaningful information gathered through all senses. The compromised ability to see with eyes need not compromise achievement when the brain learns to "see" with an in tact and heightened perceptual imaging system. Thus, self directed, intentional interaction greatly supports brain development, especially for children with sensory impairments.

      Although learning to see with compromised eyesight is natural for the brain, this process is easily disrupted by external forces which impose unnatural conditions of restriction or experiential deficits. Chief among these may be the imposition of surrogate functioning in which the functioning of the student is taken over by external agents. Students with sensory impairments often remain relatively passive while others take over without eliciting the student's self directive input - motoring the student, remote controlling the student with excessive verbal or physical guidance, choosing direction for the student. This can diminish opportunities for self directed interaction which is a key catalyst for many areas of development - especially for the perceptual and psycho-emotional system. Under these conditions, these systems either atrophy or become otherwise disrupted. Poor capacity to mature through self direction compels the development of perception and interaction with the environment through the leadership of others, rather than one's own leadership. Access to the world becomes relegated to and mediated by proxy perceivers which commandeer a degree of autonomy that should develop naturally with support. This can foster a self concept of neediness. Locus of control can become externalized, and achievement capacity is usurped by lack of self efficacy. Or, the child may become extremely demanding and controlling in order to have needs met or desires addressed by others in the absence of their own capacity to do so. This becomes restrictive when assistance is not engaged in a mutual, give and take manner.

      This pattern often develops understandably from the need to care for an infant who may have presented very real fragility. The support system may have been compelled to provide every measure of support to ensure the infant's survival. Decisions are made to address the most critical needs, and perspectives and philosophies about the niceties of the future may be put aside by the real and immediate urgencies of the moment. Then, families may not encounter professional support to ease this initially necessary and healthy pattern of dependency into a process more supportive of natural growth toward interdependence, even when parents ardently desire this shift.

      Two key requirements enable safe, efficient, and intentional movement:  remaining on a chosen course, and avoiding body contact with the environment. The perceptual imaging system naturally endeavors to reference and preview surrounding conditions in order to plan interactions. We establish intent by drawing meaning from what our senses register. When available, FlashSonar and the long cane naturally provide reference and preview information to address these movement requirements.

      Although vision seems to be the default for gathering this information, the latest in neural research suggests that, when vision is disrupted, the brain may still anticipates and seeks this information. The mechanisms involved in self direction can restore functioning by restoring these modes of information access despite vision loss. For both the blind and sighted brain, it is necessary to foster the brain's capacity to utilize referencing and preview in order to maintain self directive capacity. For sighted people, this happens relatively naturally in sighted society. As visual functioning drops, tactual/kinesthetic and auditory channels must be more intensively stimulated and applied to restore these modes of information access. Touch, hearing, residual vision, and attitude must be respected and supported with perceptual enhancement training from the first steps when patterns of self and intent are first being established.  A self concept of personal achievement must be fostered.  Children must be supported to discover their world without Nervous Nelley's hovering over every move.  Mistakes will happen, but all children, disabled or not, must learn from mistakes.  Use of the senses can be refined with instruction, but most important is that children learn that their senses are tools for achievement.  Professional instructors are the sign posts, but the family is the vehicle to make this happen, and under the right conditions it does happen.

      For blind people, hearing can become the dominant sense for conveying spatial information about the world at intermediate distances, and facilitating dynamic interactions with the world. As determined by brain scan research, the capacity of audition to discriminate, recognize, and image multiple events in dynamic space, called scene analysis, is very pronounced. In addition, a wealth of widely publicized anecdotal evidence indicates prodigious capacity. However, the auditory system remains little understood or applied. It can't be emphasized enough that hearing in blind people must be recognized and carefully cultivated for use to improve environmental interaction.

III. MATERIALS YOU MAY NEED: (For all target stimuli, transparency is ideal but not required.)

      A. Two, 1 gallon wide mouthed jars, and one jar about half the size of the others. It doesn't matter what the jars are made of, but they should be made of the same material. Plastic will be easier to handle for the exercises, but not required.

      B. Two large bowls or pots, at least 4 quarts. These can be salad bowls, mixing bowls, or whatever. Plastic is easiest to handle but not required.

      C. Three bottles of about a pint or quart - one medium mouthed and two normal mouthed of the same size as each other. Health juices and sports drinks often come in these sized bottles, with mouths slightly wider than is typical. Simple water bottles may serve for the normal mouthed.

      D. Five flat, solid, more or less square panels in the following approximate sizes: 20 inches on each side, 16 inches on a side, 12 inches, 8, and 4 inches on each side. (If circles are used instead of square, add about an inch diameter to each specification above.) Precision is not required, here. All panels should be made of the same material, but the material doesn't matter as long as the panels are hard and solid. Cardboard works. This may be obtained from a throw away box from a furniture or appliance store, or bike shop.

      E. One 20 by 40 inch piece of cardboard, folded in half to a 20 by 20 inch square.

      F. One small, portable AM/FM transistor radio. The radio is to be tuned off station on the FM dial, so you just hear static or white noise.

      G. A handheld clicker. These can be found at toy stores (in the shape of bugs or small animals) or pet stores (used for animal training).

      H. About 40 cubic inches of soft foam - enough to fill a 1 gallon jar or large bowl. This is not stirafoam, but soft, sponge like foam like that called "egg crate" foam laid over a mattress for sleeping comfort. Egg crate foam cut into fist sized pieces may be used, or soft packing foam purchased from a shipping or mailing supply store.

IV. WHAT IS DETECTABLE: This varies widely among students and circumstances. The maximum resolution of sonic, unaided, human flash based sonar is about 9 square inches (a circular or squarish target) at about 18 inches distance from the listener with a solid target presented alone in open space under quiet conditions using a sonar signal with primary frequency at about 3 kHz. This figure is general, and drawn from a synthesis of the literature and our experiences as blind users and teachers at World Access for the Blind. A pole of about an inch diameter can be perceived at about two feet. A fire hydrant may be perceived from several feet away, but not up close unless the student is very short. Likewise, a 4 inch curb is also easier to detect from distances of about 3 to 10 feet, but not too close. A chainlink fence may be detectable at 6 to 10 feet. A parked car may be perceived at 10 or 15 feet; add another 5 feet for a van or truck, another 10 feet for a bus or RVFOR me'. A tree may be detectable from 15 or 20 feet. A large building is detectable for hundreds of feet with a strong sonar signal. While features in terrains such as mounds, large rocks, up-curbs, or mud puddles may be detectable, drop-offs are almost impossible to detect. Low objects such as curbs seem taller than they are from several feet away. These may be difficult to perceive up close. Although echoes are quiet and subtle, echoes from large, hard, nearby objects are extremely pronounced once you know what to listen for. It becomes as ridiculous for blind people to run into a wall as it is for sighted people. Excuses for running into easily detectable things should not be made for blind people anymore than sighted people.

      FlashSonar struggles most with figure-ground distinction - distinguishing one object or feature from others. Elements tend to blur together - blending small elements with large. Also, high noise levels or wind can mask echoes so that they can be difficult to hear, requiring louder clicks and more scanning.

      There  are 3 primary considerations to teaching, using, and evaluating FlashSonar. These are target distinction (how detectable are the targets), environmental variables (noise and clutter), and the perceptual factors in the student (hearing issues, presence of vision, attention caapacity).

      A. Target Distinction: Targets that are very narrow, such as a pole, may not bounce back as much sound, and may be more difficult to detect. The more sparse (less dense or solid), the target, such as a fence, the larger it will probably need to be to bounce enough acoustic energy back to a human listener to be detectable and identifiable. Of particular concern with human sonar is figure ground. This concept acoustically is very similar to this same concept as it relates to vision. It has to do with the extent to which the target can be distinguished from its surroundings. Acoustically, we are talking about physical geometry and texture of the target relative to its surroundings. These need to be quite distinct for a target to register to the human audible system, but experience, concentration, and contextual clues can narrow this gap. It's hard to quantify this distinction, but we get an idea of it from the resolution data above. If a target needs to be about 9 square inches to be perceived at a distance of 18 inches from the listener, this gives us a general idea of how distinct a target needs to be in order to be registered, let alone identified. Objects that are too close to each other tend to blur together, with larger, more dense objects predominating. For example, while a person of average man size may be detectable at about 7 feet under normal conditions, that same person at the same distance may vanish if standing next to a wall or large column. However, he might still be detectable against a chainlink fence. We always gage this by ear when working with students. Ground level targets are also an issue, as the presence of the ground, together with the distance from the ears and the relatively poor angle of perspective all tend to blur ground level targets, unless they present a large surface area, or are otherwise quite distinct. A 4 inch high curb may be detectable from 9 or 10 feet, but a park bench might only register at 5 or 6, and a coffee table near a couch might not register at all. Incidentally, this is where children have a huge advantage. Their reduced height has the effect of literally making the whole world larger from the auditory perspective. They can detect shorter objects much more easily than adults whose heads are further above these same objects.

      B. Environmental Variables: Basically these include factors that increase or decrease target distinction. Noise in the environment will make sonar signals harder to hear, so targets generally need to be bigger or more solid to register, and sonar signals need to be stronger. Reverberation can have a similar effect. This could also include rain and strong wind. With strong wind, it can help to scan left and right repeatedly with the head, or incline the head such that the affect of the wind is minimized. Echoes are subtle and may be easily masked by noise, although FlashSonar can be used to extract images through moderately high noise levels. Clutter or congestion can obscure a target by causing it to blur with other targets that are too close. When teaching students, we try to choose quiet, open spaces, or focus on highly distinct targets until students become more advanced.

      C. Perceptual Variables: Here, we're talking about things like attention, visual functioning, auditory functioning, familiarity with the environment, and self confidence. We should remember that the three primary determinants for success are motivation, frequent and regular practice under self direction, and application under challenging circumstances.

      Frequent and passive use of human guide will find FlashSonar more difficult to learn. This is not to say that using human or dog guides in and of itself will disrupt perceptual development, but passive dependence on guidance will. We work on students maintaining active and mutual engagement in the guiding process. Once learned, FlashSonar can be used to allow student more freedom to move around comfortably without a guide when necessary or desired. Or, it can be used in conjunction with a guide to enrich the travel experience by heightening appreciation and awareness of the environment.

      Echoes are subtle and require one to be able to attend or at least be motivated to hear them.

      Familiarity usually increases registration. It is always easier to find a target when you know what you're looking for.

      Broadly speaking, better hearing enables the highest potential for using echoes. However, while high frequencies are required for the perception of small objects and detail on surfaces, most useful sonar skills rely more heavily on mid frequencies. Even if hearing sensitivity is reduced across large portions of the spectrum, effective sonar navigation is often possible. Unilateral hearing loss can make passive or active sonar very tricky. It is possible to echolocate with hearing aids if the aids do not interfere with the penna.

      Vigilance is perhaps the most important factor. Because there are many cues that must be analyzed and integrated for successful blind navigation, concentration is often divided among many elements. Since sonar information is relatively subtle, it requires at least a moderate degree of continued concentration for effective use.

      Finally, it is our experience that congenitally blind students are often already partly adapted to using the auditory system for imaging. However, they are often unaware of it, and their skills are usually rudimentary. They can often express what is around then once the implications of the various stimuli are pointed out, such as solid vs. sparse, but they may not have used this detail to govern their travel. They are often aware of minute stimuli, but often not aware of what it means, or how it relates to them. For example, they may often accurately describe the elements of an object or scene, but not be able to put this information together to form meaning. Once, we had a newly blinded woman participate in a workshop along side two congenitally blind rehab counselors. The congenitally blind participants would say things like, "There's a soft, kind of flattish thing in front of us, with some small, soft things behind it, and a big, hard thing behind it further away." When asked what they were looking at, they sometimes couldn't even guess. Whereas the newly blind woman, though she couldn't sense the elements, could guess accurately what they were once they were described, "It sounds like maybe a fence with some bushes behind it, and maybe a building behind that." The congenitally blind participants were hearing the elements, but not imaging them. The newly blind woman was gaining images from the verbal descriptions. We aim to help students both hear the elements, and gain images based on the elements that are heard.

V. SONAR SIGNALING

      A. Introduction: There are two kinds of sonar - passive and active. Passive sonar is reliant on incidental sounds in the environment which elicit incidental reflections, or sounds produced incidentally by the user, such as by footsteps or cane taps. The images thus extracted are relatively vague. One can use this to gain information about large features or general layout, but one is reliant on incidental noises that will not be ideal for detection of small features or fine discrimination. Active sonar involves the use of a signal produced by the listener. It allows the observer to direct actively a self generated signal into the environment. It is like the difference between taking a picture in strictly ambient lighting, or controlling the lighting by use of a "flash" or strategically placed lighting. While esthetic appreciation may favor the natural look at times, no one can argue that photos and video are always clearer and crisper with sharper detail when the scene is brought under the control of the photographer. The greater effectiveness of active sonar lies in the brain's control over and familiarity with the signal which allows it to distinguish between the characteristics of the signal it produces from those of the returning signal.  The returning signal is systematically changed by the qualities of whatever returns it, and these changes carry information about what the signal encounters.  The relative precision of active sonar is why it is used most widely in nature and in technical applications. We use the term FlashSonar, because the ideal sonar signal resembles a flash of sound, much like the flash of a camera, and the brain captures the reflection of the signal, much like the film of a camera.

      Perhaps the greatest advantage to FlashSonar is that an active signal can be produced very consistently so the brain can tune to this specific signal very intently.  This allows for relatively easy recognition of echoes even in complex or noisy environments.  It's like recognizing a familiar face or voice in a crowd. The more familiar is the voice, the easier it is to recognize. The characteristics of an active signal can also be deliberately controlled to fit situations. For example, there are two main applications of sonar in nature - orienting and targeting. Sonar used for orientation usually take the form of signals produced less frequently, and often at higher volumes. It is used to take stock of one's surroundings, to track one's position within those surroundings, and navigate through them. Targeting sonar is used to fix one's attention on one or several targets in order to gain information about the target, to intercept the target, or to avoid the target. For this, sonar signals are emitted more rapidly and with decreasing volume as the target is scanned and approached. These two uses of sonar correspond to research observations made independently in the blindness literature, that mobility can be divided into two categories - moving along (requiring maintenance of orientation), and moving toward (requiring location of a target). Finally, the brain is primed to attend to each echo by virtue of its control over the signal. Since it knows when it is about to produce a signal, the brain arouses to attend specifically to the results of that signal. It is unlikely that arousal to attention of this magnitude can be continually maintained.

      B. Some have raised concerns that clicking may be considered socially inappropriate. Our focus is on the discrete use of a click, which the user adjusts according to environmental situations. It is not generated louder or more frequently than is needed, nor is it made with facial ticks. Although it is possible to use sonar signals that are distracting, we have encountered very rare instances of the general public expressing any concern about the use of a tongue click for sonar with oup method. We have observed and our students report that the sighted public consistently does not seem to notice or care. This is true among children and adults. What is noted is that active sonar users tend to carry themselves with erect posture, they tend to interact with their environment gracefully, and they tend to look engaged. Other blind people, of course, do notice the clicking. Because of emphasized auditory attention among blind people, we find that blind people may assume that sighted people may be giving the clicks more attention than is actually the case. What sighted people do notice, and what causes heads to turn more immediately than anything else, is the long white cane.

      If arguments against the use of anything unusual had always been applied, spectacles, critical to the visual functioning of so many people in today's world, might never have been used for fear of looking strange. One could apply the same argument to using a cane, or a wheelchair, or any critical adaptive device or technique that stands out as unusual, but also changes the lives of those who use them for the better. Our perspective is that form should follow function, not the other way around. Which is more awkward: a blind person who can't find her way efficiently, gracefully and safely from one point to another, or one who gains the information needed to do so by clicking? To deprive a blind child of information that can be gained by clicking is tantamount to forcing a sighted child to go through life with eyes half-closed.

      C. The active sonar signal is the basis for the FlashSonar approach. Until technology allows us to produce a more ideal signal, we recommend certain types of tongue clicks as the ideal signal. These are intended to be unobtrusive, hands free, and completely under user control without need for reliance on external elements or circumstances.

      D. In order for sonar to be optimized, four signal characteristics must be present - user control over signal type and directionality, good alignment between signal and ears, minimal masking of the echo, and familiarity of the signal to the observer. Only an active, self generated or specially designed signal can ensure that these four criteria are met. Cane taps and footsteps may give some information, but they are reliant on the travel surface, their directionality cannot be controlled, and such signals may not possess ideal spectral characteristics. An active signal that is self generated and whose characteristics are strictly under user control present the advantage of allowing the brain to develop a familiarity with the signal. It is always easier to register something that we recognize. With familiarity, the brain can tune to the signal, and can therefore register it with less effort under broader conditions. It locks in most readily on signals that it recognizes. Also, since the signal is under the strict control of the user, the brain is always most sensitive to its effect. Bats always use active signals, and submarine technicians greatly prefer them.

      E. Tongue Clicks: Phoneticists have classified and analyzed five distinct types of tongue clicks. Their names are not important. What we want is a sharp, solid snap, click, or popping sound that the user can control to soft or loud volume. This is usually produced by pressing the blade of the tongue (flat, middle part) firmly against the roof of the mouth, then pulling sharply downward to break the vacuum. The tip of the tongue should stay more or less stationary and NOT flop down to the bottom of the mouth to form a second "pop." When the tongue does this, we call this the "cluck click." A tongue click should produce a single, sharp signal, not a double click or clucking sound. Failing the sound being produced by the blade, a respectable sound may be produced by the sides of the tongue against the mollers. This produces the "giddy up" click. Another click suitable for temporary purposes is the "tsk tsk" click, the kind we often make to express disapproval. This is produced by the tip of the tongue against the top teeth. Whatever the click, it should ideally not cause odd facial expression, or be used too often or too loudly without cause. Soft clicks should generally be used to detect targets that are close or in quiet environments.

      F. Students who use echoes are often unaware that they are doing so. Moreover, they can be unconscious of trying to elicit echoes by such behaviors as tongue clicking, hand clapping, finger snapping, foot scraping, cane banging, or yelling. What they are really trying to do should be called to their attention. If their endeavors are obtrusive, they should be redirected to more discrete and more useful behaviors.

      G. Tips for Teaching:

            1. Most students can make a suitable click without much training. Students can often learn by modeling. If students hear it enough, they eventually come to do it. For kids, we teach parents and siblings how to make the sound if the student can't do it. Usually, they can.

            2. It may help to use a popcycle stick, tongue depressor, or spoon to show the students where to place their tongue. Tongue depressors come sterilized and individually wrapped. They are available from medical supply stores; some pharmacists may carry them. A doctor's office may provide a few as samples. Spoons are easy to obtain. Enlisting the help of a speech and language therapist may also help, if one is available. (They may also have some tongue depressors.)

            3. A click that we try to avoid is what we call the "cluck click." This is a double click in which the tip of the tongue slaps against the bottom of the mouth. We want a sharp, single click similar to a finger snap or the pop of chewing gum.

            4. For students who struggle to make a click, we teach tongue awareness. We identify two parts of the tongue - the tip (the forward part used to make sounds like "t," "d," and "l", and the blade of the tongue, used to make sounds like "k", "g," and "ng" combination. Have the student make these sounds. Have the student try to make a click sound while the student very gently presses a spoon or something beneath the tip of the tongue, just to provide some feedback to remind the tongue not to drop. Sometimes, this alone helps the student make a useful click.

            5. If not, we inform the student that the click we may be looking for is formed with the same part of the tongue and mouth used to make the "k," "g," and "ng" sounds. Have the student hold the tip of the tongue still with the spoon while making these other sounds. Have the student try to alternate between making these other sounds, and a tongue click. Typically, a student can do this. It may help the student to imagine that a blob of peanut butter is stuck on the roof of the mouth, and he must use the blade of the tongue to pull the peanut butter away. The center of the tongue should be pressed to the roof of the mouth to create pressure, then pulled away quickly and forcefully, producing a distinct click. If a click is juicey or "sloppy" to begin with, it will usually tighten up or sharpen with a little time.

            6. If the student just can't make any suitable click at first, have them produce a "ch ch" sound.

      H. Handheld clickers may be used for certain circumstances. The clicker should be cupped in the hand, button facing outward and forward, and activated by the thumb. Clickers should be sounded either at waist level or above the head, never near the ears. At least 1 second should span between press and release of the button. Clickers should never be activated rapidly, and should only be used out of doors or in open environments.

      I. For very beginning exercises, some students may benefit from making a continuous "shshshsh" sound, or just using their voice. Some students may not have the breath support to make long "shshshsh" sounds. If this is the case, the transistor radio tuned off station (see III-F) may help. This should be held just below the student's chin.

VI. INSTRUCTIONAL STRATEGIES.

      A. Introduction: We believe the brain learns to see by using systematic stimulus differentiation. This natural process may be sped up with formal instruction. The process of helping someone to learn FlashSonar involves tickling the brain into registering and processing subtle stimuli that may be beyond the conscious experience of the student. These stimuli often flow through our perception without conscious awareness, and the neural system may not have developed the full capacity to register or react to these stimuli. As instructors, we must help the student to "hook in" to these stimuli so that channels of processing these stimuli can be opened and made alive. The opening of these channels is often accompanied by a spontaneous sense or expression of excitement or sudden realization - the "ahha!" experience. This involves helping students to register and process stronger or more intense stimuli so that the brain may then open to processing subtler and finer stimuli. Perception of and reaction to the stimuli is key. For this to happen, the instructor helps the student to develop a relationship with the stimuli. Six strategies may help to do this - stimulus sensitization, stimulus clarification, stimulus comparison, stimulus association, stimulus shift, and refocusing. we'll give a general discussion of each strategy, and then more specifics as they apply to the specific activities.

      B. Observation: It is important to know what passive or active sonar skills the student is already using. Take plenty of time to observe the student's existing sonar skills. This can be done during other lessons. For example, instead of requiring him to trail along a hallway, allow or encourage him to walk down the hallway in his own way. See if he is able to direct his course between the two walls. See if he seems to be able to perceive when a wall or door is in front of him. Observe if the student stops independently or hesitates before contacting objects in the environment. How directed are his movements? If the student is able to do these things, he may be demonstrating some basic sonar skills. Some children demonstrate good skills at an early age with no instruction, but good instruction always helps improve skills.

      C. Stimulus Sensitization: As this term implies, we are helping students to "sensitize" to subtle stimuli, helping students to "hook in" to the experience. We start with sensitizing students to echoes, usually by having them detect and locate targets that are easy, such as large plastic panels or bowls. This helps them get a sense of what echoes sound like. Once this is established, we move to subtler and more complex stimuli. We find the level of stimuli into which they can "hook", then gradually move to subtler stimuli. Many students will pass through the earlier, more obvious stimuli very quickly, while others will need more time.

            1. Noticing Strong Echoes. When the student is moving around the house or other environments, help her to notice the presence of strong echoes. For example, many children who are blind love to play sound games in highly reverberate environments such as rest rooms, breeze ways, or stair wells. Encourage the child to sing, repeat words after you, or clap in the bathroom or garage or other large, uncarpeted places without a lot of furniture or other objects that absorb sound. If the child makes noise in places with strong echoes, she can notice that her voice sounds different in these places than in other places. You can also make a noise in the bathroom and then move quickly out into the hallway where there is less echo, and make the same noise there so that the child can compare. Corners in a room also usually emit stronger echoes than other areas of the room.

            2. The bottles are intended to give clear examples of hearing differences in the environment. They're used to prove a point. One can make the point that the sounds made by musical instruments, even though they may sound hugely varied to us, are actually the result of very minor changes in the instrument itself. A very small shift of one's finger on a guitar or position of a bow on a violin, or change of fingering on a flute produces a huge change in the experience of the ear.

                  a. The student should be able to tell by ear when a liquid is reaching the top of the mid mouthed bottle or glass without touching. Liquids may be poured at different speeds to ensure the student is listening, and not just timing.

                  b. Put slightly different amounts of water in each of the two standard mouthed bottles. The student should be able to hear the difference when blowing across the bottles, even if it is very slight. Only an extra tablespoon of water in one of the bottles will make it sound noticeably different. Students should be able to tell which one is the higher or lower pitch. If the student can't, increase the difference a little more at first. Again, the point is simply to begin heightening auditory sensitivity to changes that are more obvious before moving on to those which are more subtle.

            3. The phase effect:

                  a. Using the radio at low volume or a "shshsh" sound, or continuous vocal tone "aaaaaaah", move the large, solid panel from above or behind the student's head, to directly in front of their face. The panel should seem to appear suddenly before them. Don't move the panel too quickly, as the sound of your arm or the wind burst from the panel may arouse the student's attention. Be sure they can tell the difference between the panel being there vs. not there. If they can't, then move to the solid bowl (see stimulus clarification - Vi-D), or the jar. Once the student can hear the presence, then do the same thing with the large, flat panel further away.

                  b. Next, try slowly waving the panel toward and away from the student's face. Discuss the change in phase as the panel moves. Can the student tell when the panel moves? Can they tell when it is just about to touch them? If not, try with the bowl, then move back to the panel. (This is an example of stimulus clarification.)

                  c. Finally, move the panel from in front to the left, and from in front to the right. Have student say which way it moved. Keep the flat surface of the panel facing the student's head. In other words, don't just move the panel laterally along a plain from left to right, but move it along a circumference circumscribing the student's head such that the surface is always pointing at the student. Have the student practice scanning to hear when their "shshsh" sounds different. Or, by this time, the student may already be using a tongue click. This is encouraged.

                  d. Note: While clarifying the stimulus (see Vi-D) using the salad bowl can be helpful, we don't always start out these particular sensitization exercises with the salad bowl, because the concaved surface, while more intense, can blur the clear phase shift affect that we want students to tune into. It's better if they can get it without resorting to the bowl, but not a crime if they need the bowl.

            4. Stimulus Target Presentation: These include the jars and various panels (see III). These are always presented to students with the instructor standing behind the student so that the instructor's presence does not interfere with the detection of the stimulus targets. These exercises should ideally be done in a large, open, nonreverberant, fairly quiet space (not absolutely quiet; about the noise level of a quiet day in a suburban residential neighborhood). If there are constant noises in the area, such as air conditioning or traffic, it's ideal if the noise is more or less evenly diffused throughout the environment so that it lacks directionality. If the noise is directional, then it should be placed behind the student so that sound shadows do not interfere with cuing of reflected sounds. If the exercises are performed in a large room, be sure the student is not facing a wall or corner that is too close to them. The stimuli are presented around the head as quietly as possible. It is best for the instructor not to wear long sleeves, because clothing rustles. When presenting a stimulus to one side of the head, the instructor should move both arms, including the empty one, but keep the elbow of the empty arm bent so that that arm is kept out of the student's auditory view. Moving both arms will keep the student from just cuing off the arm that moves, since they both are moving. But by bending one arm, the student won't be distracted or confused by the presence of the empty arm.

            In general, these basic stimulus sensitization exercises move from presenting the jars first, then the bowl, then the flat panels. We generally move from the large flat panels to the smaller ones over time. We start at very near distances before moving to arm's length. Even if students seem well ahead of the game in their sonar, it isn't a bad idea to just zip through all the easy exercises anyway. It can give material to refer back to when the exercises get more complex. We always start with teaching the student simply to detect the presence or absence of stimuli, before moving on to location (left, right, high, or low). The various stimuli can be brought up later to represent real features of the environment - chambers of various sizes, alcoves, corners, and walls. The students will often be slow and methodical at first in giving their answers, but we want them to reach the point when they can instantly and almost casually give the correct answer without hesitation or second guessing.

                  a. Sample Exercises:

                        (1) Present single large jar at various locations, and test detection. Discuss the sound. Start close, then move further back. Then, discuss the difference in sound between the large and small jar. First, present them individually, then present both at the same time, one to each side, having the student turn his head side to side to click or make some suitable noise into each. Discuss the difference between the size. Next, fill one of the large jars with foam, and repeat the stimulus differentiation exercise, discussing the difference.

                        (2) Compare the "bowl" sound to the "jar" sound. The jar may sound more hollow than the bowl, more like a chamber. Also, present the large bowls to each ear simultaneously but at different distances. Have student state which is further, which is closer. Start with very different distances, then reduce the difference.

                        (3) Repeat above exercise template using the flat panels, but don't compare size; compare panel to bowl, bowl to jar, panel to bowl or jar, etc. It may help to present both stimuli together to right and left, rather than alternating. Student can say, "the bowl is on the right; the panel is on the left." Or, "there's a panel above me and also one to the right." Discuss the differences in sound. Again, the bowl should sound more hollow than the flat panels. Also, the panel exercises should be done interspersed among other exercises (see below), not in an unbroken series. Encourage students to scan with their heads to differentiate the presence from absence of the panel from one side to the other. When doing distance differentiation, never use different sized panels, but always the same size.

                        (4) After doing a few of the exercises above, present the long piece of cardboard folded at 90 degrees as a corner, but don't tell the student what it is. Discuss what it sounds like, and what environmental feature it may represent.

                        (5) The exercises above can and should be repeated using real environmental features, such as blank walls, fences, and rooms of various sizes. Students can place their back, front, and each shoulder to a wall or fence after being disoriented. Start at a distance of about a meter, then increase to perhaps 20 meters. Note that some students may find sonar characteristics easier to hear at first from greater rather than lesser distances. Real environment exercises needn't be put off until all panel exercises are complete. They can be conducted between and among the panel exercises for the sake of variety and stimulation. It is often useful to the student to start to see the application of these exercises early in the program as this may not be self apparent, especially for young ones. In fact, young ones may not stand long for these silly drill exercises; they will probably need a more experiential approach involving real features most of the time. In general young ones do learn better when movement is involved.

                  b. Special Considerations:

                        (1) If students can't do a tongue click (see V), have them use a "ch ch" sound instead.

                        (2) If students have difficulty detecting these targets using a pulsed signal, try using "shshsh" or the radio at low volume placed at chin level. It may help to move the panel toward and away from the face with the continuous signal, and discuss the sound of the change. Can the student tell when the panel or bowl moves? Can they hear it move from side to side, and which side?

                        (3) If students don't seem to be able to hear the objects, try detection of large walls at distances of 15 or 20 feet. Discuss what the sound is like, a distinct echo, as we turn in different directions. Discuss how the sound changes as we get closer or further away. A pulsed signal gets closer or further from its echo. As we get real close the echo merges with the signal. Once the student understands the sound of presence, go back to the panels.

      D. Stimulus Clarification: When students are unable to register or describe a stimulus consistently, it may be that the stimulus needs to be clarified. There are generally three ways to do this.

            1. Representation: a similar but more detectable stimulus may be used. For example, if a student cannot detect an opening in a wall, say an open door, find a room that is highly reverberant (larger or less furnished) that the student can hear more clearly as he or she passes the opening. Another example might be if a student has difficulty locating interior corners, he will likely be better able to find a large alcove. One can discuss the sound of an alcove, and relate it to the similar but less "hollow" sound of a corner. Alcoves and corners tend to be easy to detect and locate, because they throw back most of the acoustic energy to the sonar user.

            2. Intensification: Bring the student closer to the stimulus, or use a larger version of the stimulus, such as increasing the size of the open door or branching corridor. This serves to intensify the stimulus under investigation.

            3. Elumination: use a different sonar signal for that exercise. If the student can't detect the stimulus with a pulsed signal, such as a click, perhaps she can with the radio or clicker. This strategy sheds a different "light" on the stimulus that may cause it to stand out so the student can detect it more easily. Then, go back to using a tongue click.

      E. Stimulus Comparison: It may help to compare directly one stimulus with another. This is particularly useful when instructing registration of feature characteristics - dimension (height, breadth), location, and density (see IV). It may help the student to register these signature types when they have a basis for immediate comparison. For example, if a student is having difficulty registering foliage, confusing it with various types of fencing, it may help to find a location where both types of stimuli are immediately available. One can find locations to compare trees to poles, retaining walls to hedges, a car to a truck, a building with an awning to one without, a wall to steps, a wroughtiron fence to chainlink, etc.

      F. Stimulus Association: Stimulus association is the conceptual version of stimulus comparison. Instead of comparing elements in the environment, we are comparing them in our minds by drawing upon mental references. For example, when facing a hedge, a student might say, "It sounds solid?" I might reply, "as solid as the wall to your house?" "No, not that solid," she might reply. "As sparse as the fence of your yard?" "No, more solid than that," she might answer. Now we have a range of relativity to work with. "Does it remind you of anything else near your house, maybe in the side yard?" "Bushes?" she might query. "But what seems different from those bushes?" "These are sort of flat like a fence." If she can't put the word to it, we have her touch to determine that it's a hedge, and we may discuss why it sounds the way it does. This strategy is often used in discussing and describing stimuli. As students build up more of a repertoire of experience and understanding of acoustic imaging concepts, they can draw on this experiential base to understand and work out new stimuli. For example, when a student is having difficulty identifying or describing a feature, such as a palm tree (because of its seemingly solid, flat branches), one might ask "what does it remind you of? What are its characteristics?" We might discuss other trees we've encountered, and talk about how this one seems similar and different. When we are learning to find entrances to buildings, we often discuss what alcoves sound like. When finding open doors, we may discuss what branching corridors sound like. When learning to cross a street toward a building on the opposite corner, we may talk about what it was like to cross the open field or parking lot to a building on the other side. We often refer to beginning exercises when coming to understand the more advanced ones.

      G. Stimulus Shift: The stimulus shift paradigm is used by psycho-physicists to teach a student (subject) to register and respond to one stimulus by substituting another, more powerful stimulus, then fading that stimulus gradually so that perception of the subtler stimulus builds. For example, a student may have difficulty finding and approaching a tree trunk. The canopy of the branches can obscure the trunk. It may help to place the radio at the trunk, and have the student approach that at first. The student gains experience orienting toward and approaching a sound source. At first, the student is reliant on the sound source. But, the sound source is reduced gradually in volume. Without realizing it, as if by magic, the nervous system gradually keys into the echo stimulus as if the radio were still on. It's a kind of neurological bate and switch - a way of tricking the brain into thinking it's responding to one stimulus, when it has really learned to adapt to and register and respond to another.

      H. Attention Stabilization: Many students may not be accustomed to placing their motor system under the guidance of their auditory system. Also, congenitally blind children often tend to focus their attention into their heads, or on to matters of cognition other than the physical environment, such as the social environment. They often focus on what we call "in the head" environment, or focus on social engagement with a high degree of linguistic rather than spatial processing. There's nothing wrong with these focuses, but we'd like to encourage a balance. Recent blindness, or long time lack of self directed movement will exacerbate these tendencies. The perceptual system often becomes disrupted by passive reliance on guidance on the part of supporters and professionals. The inter-connection between the motor and visual systems is well established, but the inter-connectedness between the motor and auditory systems, other than for balance through the vestibular system, is much less understood. It is often assumed among perception experts to be of no great affect, but there are notable disagreements on this point, and this controversy is beginning to fade with new data. Whatever the case, it is probably true that the auditory-motor connection is more tenuous than the visual-motor connection. For this reason, the auditory-motor connection often appears to benefit from an "assist" development. In trying to work out this connection, the perceptual system may become confused or overloaded at times for some students, requiring a moment of pause and refocus. This can be facilitated by an instructional agent. For example, when asked to locate an object or to move in a circle around one, students may begin to meander near or around the object, eventually wandering away from it without realizing it. They may do this even when they know where the object is. It often helps simply to bring the student's attention back by asking, "where is that pole?" Or, it may help to instruct them to "stop, face it, now go for it." Students can do this surprisingly well. On one occasion, we were working with a sighted person under blindfold for a TV segment. He was learning to find a minivan in an empty parking lot up to 20 feet away from his starting position. He had had two or three successful finds, and we had increased the distance. As he was searching, we could tell by his body movements that, consciously or not, his perceptual system had registered and noted its location, though still tenuously. But, the presence of the camera man was pulling his attention off track, and he began to wander. I told him, "You know where it is. Don't let the camera man pull you're attention away from your objective. Re-establish your course. Trust in what you know." At that his wavering reduced, and he pendulumed his way back on track as if drawn by a distant magnet until he reached the van. He reported that helping him refocus at that crucial moment was essential. Helping the student stop and refocus before they get too far off track can actually help them to adopt good perceptual habits of presence of mind, attentiveness, maintenance of conscious awareness, and self-trust. Usually, this is best achieved by asking strategic questions or dropping thought provoking hints, rather than by giving directives, descriptions, or explanations.

      Some students' attention just seems to be everywhere but on the activity at hand or the environment around them. Many students develop a coping mechanism of accessing the environment through others, rather than by their own self direction. To an extent, this can be adaptive as long as it doesn't limit the student's opportunities for activity, or pose an undue burden to others. Again, we look for balance. Other students may just be stuck in perseverative language about anything and everything except what's happening now. Or, they may get stuck on a sound or texture, and be unable to move on in their attention. With some students, we may set down parameters of interaction. For example, we may explain to the student that we will engage the student's conversation when that conversation pertains to the immediate activity, or to the immediate environment. Conversation about anything else will not be engaged.

      Another approach often found helpful is placing a bean bag on each shoulder, or perhaps the top of the head. This often has an amazing affect on the student's ability to slow down and focus. Rather than pose a distraction, the process of keeping the bean bags from falling seems to heighten attention globally. It has been found useful in remediating certain reading and learning difficulties in sighted kids. It may do this by causeaing an automatic bio-feedback loop, which gently encourages attention. It can also keep those bouncey, jiggley kids from bouncing and jiggling too much. Placing the bean bags in spare plastic produce bags may increase the affect, because it's easier to hear the bag when it falls. For students who are reluctant to do this, We may make it a kind of game by wearing the bean bags ourselves, and seeing who can do it the longest. We let the students know that we are willing to engage in whatever task or activity we pose for them; that's only fair.

      I. A Couple Instructional Considerations:

            1. For cane users, it is our experience that the program is most effective when conducted with the student using a cane. At first, we separated auditory and cane training, but have sense found that combining them has best results. It is true that the student may find the exercises easier without the cane, but we feel that for most students the pay off is usually greater and speedier if the cane is used from the beginning. It can be quite frustrating for both student and instructor to have students perform the exercises well without the cane, only to have their hard earned performance fall apart when the cane is re-introduced. Use of the cane facilitates self directed discovery and, for most students, there is much to be said about the stimulating affects of self directed discovery on perceptual development.

            2. Visual functioning generally interferes with sonar information as it tends to dominate the attention (for better or worse). However, it is surprising how motivated many partially sighted students can be to learning FlashSonar. They often know just how dependent they are on the little vision they have, and when the lights go down, they go down hard on these students. FlashSonar seems to be particularly helpful to students who have visual field loss, as students can learn to use it to fill in these gaps. For these students, FlashSonar will often serve to allow the students to register objects or features outside their visual field. Then, they may bring their vision to bear on the target to gather more information. This method can reduce the need for constant visual scanning. For partially sighted students, we find that it seems more effective to isolate and integrate. At least 50% of lessons should be done under blindfold. During auditory image training, the visual system is literally adapting to process nonvisual information to extract spatial images. For this to happen, the visual system seems to need a period of disconnect from the eyes. It seems to be hard wired to receive and process images from the eyes by default, so it needs to be insulated from the eyes in order to foster new connections and operative pathways for nonvisual information. Since partially sighted students are using their vision most of the time between lessons, they tend to learn auditory imaging more slowly. However, they sometimes have an advantage in that they may have visual images to draw upon in learning how to image nonvisually. In other words, the imaging system seems to be able to apply previous visual experience to developing a nonvisual imaging process. Students with light perception or visual memories often confuse sonar images with visual images. They seem to "see" what they hear. They may say: "I can still see the wall," even under a blindfold. The brain can interpret sonar sensation in a visual reference - causing confusion between the sensory channels. With the exception of very young children, you must explain to students the difference between what they see, and what they hear. The strategic use of blindfolds and isolating headphones or earplugs can be helpful here. Some with poor vision will strain their eyes. But when their use of echoes is brought to their attention and refined, they may find it less necessary to strain. This is especially beneficial to those with fragile eye conditions.

            3. Although the basic principals are pretty much the same for all students, there may be some differences working with recently blind adults, as opposed to those blind for a long time. For adults, research has shown, and it is our experience, that a neuralogical adaptation seems to take place, at least in part, over about 5 years. For children, this may occur in only a year or two. It is as if the nonvisual channels have warmed up. However, these channels may be sluggish for recently blind adults. The situation may be somewhat reversed for newly blind adults, vs. congenitally blind people. In the former, the imaging system may be in tact, craving and reaching for information, ready to assimilate it into a dynamic, operational image, as it was accustomed to doing with vision. Yet, the nonvisual channels through which to gather this information may not be forth-coming as yet. On the otherhand, congenitally blind people may have moderately active channels for conveying nonvisual information, more or less, but if the student is relatively dependent or restricted, the imaging systems may be under-developed. For recently blind people, the full complement of abilities should be learnable to a functional level of proficiency. But, this will likely take longer and require more diligence on the part of the student. Developing these nonvisual channels may need to be addressed with care so as not to discourage the student. However, within a few hours, many students report and express an "ahha!" moment in which the echoes flash at them. They often report this as visual, and sometimes become quite delighted at the experience. Here they are seeing something when they had resigned themselves to never seeing anything again. We often foster this development by addressing their strengths which usually lie in an in tact imaging system. I will provide two examples:

      First, during a workshop, I worked with a blind woman who had lost her vision only a few months before. She was still quite emotional about it, but she was very motivated and enthusiastic. It was a struggle to foster development of even the basic skills. She was one who didn't warm up to the panel exercises. For sensitization work, we had to clarify those stimuli by using actual walls and corners. One of the exercises involved having her walk along a library book shelf, and stop where the shelves were empty (which gave off a decidedly hollower sound. If memory serves (this was 7 years ago), this was her first "ahha!" moment. Her exclaiming "ahha!" is what gave this technical term its name. Though she made huge progress and expressed her appreciations most wholeheartedly, she did not reach the more advanced abilities. The audience of attendees asked two congenitally blind rehab counselors from among them if they wouldn't mind undergoing some training in the advanced skills, to which they graciously agreed. Here's where the imaging differences were demonstrated. When it came to auditory scene analysis, the congenitally blind adults were good at detecting and describing various stimuli, but couldn't articulate the scene. Whereas the recently blind woman, once she heard the others describe the stimuli, could do so. For instance, when looking at someone's front yard, the congenitally blind adults might say, "There's something broad, tall, and sparse immediately in front of me. Behind it, there seems to be something tall but not so broad, maybe broader near the top. It sounds more solid. Then, behind that and further away, there seems to be something large and very solid." But, they often couldn't hazard a guess as to what they were looking at from a "big picture" perspective. The recently blind woman would then chime in and say, "Wouldn't this maybe be a fence with a tree behind it, and maybe someone's house behind that?"

      On another occasion, I was working with a teenaged boy blind for one year. I began with him by having him show me around his neighborhood in which he'd grown up. I instructed him to call to mind everything around him as vividly as he could remember. "Take me on a tour, and describe everything as if you were seeing it." This process seemed to stimulate his receptivity to the opening of nonvisual channels, and I posit that this may be true for many. Don't be afraid to get very visual with your recently blind clients, while at the same time applying the exercise activities to open nonvisual channels.

                  4. When working with congenitally blind kids, we do not spend much time specifically on body concepts, backwards chaining (tactile landmarking), or focusing on the minutia of things like doors, chairs, or whatever else we might falsely assume the child doesn't know "because they can't see it." Our focus is on child directed (but adult facilitated) discovery. My spatial movement skills as a boy were impeccable, as were most of my gross and fine motor skills. I could find my way around anywhere, and take anything apart and put it back together. Yet, I probably would have scored low on things like body concept, had there been anyone to assess such a thing (God forbid). I didn't know my right from my left till I was 8. I couldn't tie my shoes till I was 9. When I swung my arms hard enough, my hands touched something behind me. I don't know how long it took me to figure out that my hands were just touching each other. I was absolutely convinced for ages that the deep end of the pool had no bottom at all, and would have screaming fits if they tried to make me go there. I believed that there was a hill at every stop light. (Ever notice the car seems to pitch forward when you put on the brakes?) Yet, my travel skills were top notch even at 3 years old. Not only do we not think that body concept training is particularly important, we don't really think we have any way of assessing it properly, or determining what the results of such assessments actually mean. It seems to be assumed a priori that congenitally blind kids will have problems with body and other spatial concepts. We have not found this, if the blind child has plenty of opportunity to explore and discover. This is the basis of many of our lessons with congenitally blind kids, and of our work with their families. It is in no way based on the things they shouldn't be doing, but on the freedoms they should be enjoying.

            5. Working with very young children: We're not much of believers in instruction that is very structured. We take a perception/discovery approach, rather than a skills based approach. This tack seems to work particularly well with very young children. The youngest child we've taught cane training to was 18 months. The youngest child we've taught FlashSonar to was 2. However, We don't believe there's a minimum age. We might ask ourselves "how young can a child start to learn to see." The answer is that children start to learn to see from birth. Likewise, learning to "see" without sight can begin at birth with the right support. In general, we would say that experiential lessons in discovery are most effective with children. Engage children in what they like to do, which is usually play, and work sonar experiences into these. Also, we can't emphasize enough how critical and successful we have found working with the family. Family buy in can increase the student's success 10 fold. The following few examples may be helpful:

                  a. Find the box: Very young toddlers or infants often like to crawl into or under things. Find a large container, maybe a rubbermade storage container, or an open cardboard, and position the child near it. Entice the child by talking or making funny noises into it to get their attention. "See how boomy it sounds. Rrrrummmm." Then, see if you can get the child to find it themselves. The first time should be easy, because they heard you talk into it. But then, place the child at different distances and different angles, and encourage them to find it.

                  b. Hide and seek: For older children, we might set up a game of hide and seek. This works well for groups of blind kids. The rules are that one child counts to whatever while the others hide. They must hide near, under, or behind something that is at least as big as they are. This means that they have to find such objects. Then, the seeker has to "look" for objects of a certain size, and check if anyone is there. If the seeker has trouble, she can ask for a hint. The hiders must clap their hands once, and the seeker needs to keep track of where she heard the signals coming from. You can set a limit on how many hints the seeker can ask for. We've found that kids generally very much enjoy this game.

                  c. Ball play: You can audify a ball quite easily by placing it into a spare grocery bag, and tieing the handles together loosely around the ball. Then, we may bounce the ball against the wall, and intercept it as it comes back. If the student has to chase after the ball, he must maintain echo awareness to return to a point within tossing distance from the wall, and square himself so the wall is in front. Otherwise, the ball will just continue to bounce away eskew.

                  d. Explorer: Here, there is no real goal to the lesson, other than to explore. We find an area or large building that we think will be of interest to the child. Children often like large buildings with lots of corridors, stairways, elevators, and rooms of different types. We try our best to find everything interesting, and we try our best to keep track of where we are. We listen for differences in our surroundings, and keep track of whether things sound familiar or different. This exercise can also be performed in an intriguing outdoor area, such as a park. If this park has a playground or nice trees to climb, so much the better. In one park, there were large stone monuments, and a large fountain with steps that went up and around it - quite fascinating to explore, and wonderful to play hide and seek in.

                  e. One student liked to ice skate. We practiced having him ice skate around the rink while keeping track of the outer railing, and listening for others around him. Another young student liked to ride his tricycle, so we found an area which had a very long wall, which had some twists and turns in it. He could ride his tricycle along the wall as much as he liked, and as fast as he liked. He could even venture away from the wall, as long as he could hear it well enough to return to it.

                  f. Counting: Many students like to count things. By using FlashSonar, students can count poles, parked cars, trees, bushes, or open doorways. To do this, they need to be able to detect and discriminate what the objects are.

VII.  Key Components of Instructional Methodology: The following may be preaching to the choir for many of you, but we offer this in friendliness.

      A.  Student Centered Instruction:  Based on the person centered approach of Dr. Karl Rogers, we make every endeavor to place primary emphasis on the student's style and need of learning, rather than instructor's agenda or body of knowledge.  The student is the nucleus of instruction, not the instructor. We believe not so much in teaching a student our knowledge, but in fostering a student's ability to learn. It is more about drawing out the learning process, The emphasis, therefore, is on how students learn and what seems salient to them, not on what the instructor feels they should teach, although instructors do share their body of knowledge and perspective as appropriate. Also, communication is carefully fostered with the student to understand the student's phenomenalogical frame of reference - how does a student perceive his world, himself, and others around him through his senses and his mentality.

      B.  Self Directed Discovery:  This is the most natural way for the brain to learn, and allows most generalization to the most varied situations. Effective teaching is about helping students develop a dynamic means of establishing a relationship with the world for themselves based on their direct awareness of the environment through their own senses. In this way, they form their own comprehension of what is accurate, effective, adaptive, and what gives them the best access to what they want and need. We help students to acquire a set of achievement oriented, self directive abilities through their active participation in and direction of the learning process. It occurs in challenge situations which may be engineered or facilitated by the instructor which the student must discover a way to address. Thus, the instructor can help to reinforce and generalize the development of this array of self directive abilities. It is done in a more constructivist and less didactic method. The student's intrinsic perceptual feedback and comprehension processes are the primary source of learning rather than extrinsic feedback from the instructor. Thus, control of the learning process rests primarily with student centered factors.

      C.  Strategic Questioning:  In general, the best instructor feedback to students is thought provoking questions.  "What can you tell me about that?  What do you think it is?  Where do you think it comes from?  What does it seem like?  What brought it here? What can you do or not do with it?" and so on.  Rather than giving away information, it is usually best (although not always practical or feasible) to encourage the student to discover answers through investigation and critical thinking.  "Shall we go find out? How do we get there?"  This approach respects what students have going on in their head, and respects and nurtures their capacity to learn and grow from information they acquire for themselves from the environment.  Questions to students that promote discovery tend to engage and develop the higher brain functions of cognition and perceptual processing, whereas informative feedback or directive prompts (telling the student what's around and what to do) tends to trigger and reinforce more primitive brain activity associated with action and reaction. Stimulating higher brain function leads to better self direction toward higher achievement in a complex, modern world.  To this end, as a rule, our interactions tend to take the form of questions about 3 times more often than answers or directive prompts.

      D.  Commitment to Sovereign Student Right to Accessing Societal Resources:  Our approach assumes a priori that all students have the sovereign right to opportunities to participate equitably in society at all levels, according to informed choice and personal responsibility. These rights are broken down according to access to the physical, symbolic, social, psychological, physiological, and spiritual environments with reference to societal engagement. This does not mean that it is society's responsibility to facilitate a blind person's ability to engage every aspect of the world equivalent to everyone else. We recognize that blindness can present fundamental challenges to accessing many aspects of the environment. Vision makes use of light which provides a level of detailed resolution that no other sense can come close to matching under circumstances in which light is particularly useful. It is not necessarily society's responsibility to change that basic fact. However, to the extent to which society makes itself and its exchange of goods, services, and companionship available to its members, we affirm that it is in society's best interest to make every effort to involve all its members, including blind people, equitably in this exchange process. Thus, we consider access to societal resources to be a sovereign right. Full access to these resources optimizes self directed, achievement in society, and quality of life. Our goals and objectives are not about what a student needs, because the needs are already self evident - all students "need" to have their sovereign right to access societal resources honoured, respected, and facilitated as necessary and appropriate. Our goals and objectives are about strategies to meet these needs. We assume that these needs can be addressed respectfully for all students whose learning style is understood, regardless of the extent of impairment, given appropriate strategies and recognition of basic challenges. We further assume that most students are capable of learning when the learning style is understood, and that the motivation of most students can be encouraged or triggered by a respectful recognition of the student's potential, and commitment to their need for access. When we maintain sight of the basic need, our strategies remain true to that need, and do not become obscured by factors not relevant to the student.

      E.  Rapport: There is a necessity for rapport based on trust, respect, and amiability. This is imperative, because this provides the student with the security to help them face challenges with improved adaptation. There is a difference between tension and stress. The healthy tension of facing challenge can help us access the psychological and physiological resources to assimilate new information in order to meet challenges. Stress or distress can impede access to these same resources. In other words, a distressed organism tends not to be able to adapt to a novel situation and regain equilibrium. When there is good rapport, the student can tune into the relative stability of the teacher, and learn to access these resources by a kind of empathic modeling. The teacher can also scaffold the discovery process and provide reassurance where appropriate. By providing a kind of security through camaraderie, the teacher frees the student to engage the equilibration process to face the challenge more adaptively.

      F.  Teachers are Learners First: The most effective teachers are the most willing learners. One way to help maintain respect for the student's learning process is to see ourselves always as learners first, and to open ourselves to learning from and with our students as much as we teach. We remain always engaged in the discovery process with our students, rather than conducting the process for them. If we are not learning as much as we think we're teaching, than we may not be teaching as much as we think.

      G.  Systems Dynamics:  In respecting the student as the nucleus of the instructional process, we address dynamics of the entire system connected to the student. This includes their immediate family (first and foremost), extended family, friends and associates, immediate community (school, work, neighborhood), and anyone working with the student in a professional capacity. The dynamics of the system will always maintain more impact on a student than a single instructor. Therefore, we consider it essential to address the entire system to cultivate a fertile, broadly supportive context for student learning and growth. Most learning does not occur during instructional sessions, but in the application outside instructional sessions. When the system dynamic is open to and supporting of the learning process, opportunities for learning greatly increase in quality and quantity.

      H. Accessing similar perspectives: We make sure in our work with students, wherever possible, that we access individuals who have extended and experience similar to the student's condition. We try to enlist people with certain type of partial vision that may resemble the student's, total blindness, or other health complications. Where possible, we try to involve these individuals and the development and implementation of the instructional process. For example, having a partially sighted person help in teaching a monocular lesson, or lesson in using a CCTV, Or gaining insight into how a partially sighted student might see and why.

      In short, do not settle for the minimum requirements for functioning, but instead reaches for the limits beyond our limits. We work with our students to help them understand that they have the ability to direct their own lives rich with quality, promise, and as much excitement and intrigue as they could wish for. They need not passively rely on the good graces of others, but can make it on their own good graces, and share these graces in a worthy manner with others.

VIII. ESTABLISHING ORIENTATION RELATIVE TO POINTS OF REFERENCE

      A. Maintaining various facing relative to a flat surface (see exercise Vi-C-4-a-(5)).

      B. Orienting to and moving toward an object: Position student about 8 feet from a wall and ask him to approach the wall directly. Increase the distance over time to 60 feet or more. Some students may need to be reminded to face the wall first before moving toward it. If student has difficulty with this, it may help to place a sound source (the radio) at the wall, and gradually reduce the volume of the radio so that the sonar sense will take over (see VI-G). It may also be easier for some students to localize and approach walls more distant first, then closer. For some students, the time delay aspect of sonar at distances is easier to hear than phase cancellation at close distances. Students should also learn to approach smaller objects, such as a pole, tree, or bush. It is common for children to meander around an object, even when they know where it is. It is as if they're nervous system hasn't attached movement to auditory perception, such that auditory perception can guide movement. The student may need to practice turning first, then moving toward the pole. Finding the trunk of a tree may also be done, but the presence of the canopy may reduce the figure ground of the trunk.

      C. Student should practice moving toward a wall from a distance, then gracefully turning before reaching the wall and walking parallel to the wall.

      D. Alcove and interior corner location: This is simply an activity to learn to find a corner. A corner is needed with at least 3 meters of clear space before it. This may include detection of alcoves, such as an entrance alcove. This can be done in an auditorium setting. The student is positioned so that he is facing oblique to the corner. The student practices turning and moving directly to the corner. Some students may need to be reminded to turn their body first to face the corner, then move toward it. Distance should increase to about 15 feet. One can have a student move from one corner of a room diagonally to the other, sensing the opening of the corner behind them as they move away, and the closing in of the corner in front of them as they move toward. The room can be 15 by 15 at first, but then larger rooms should be used. It can also help to place various obstacles in the way, between the corners. The student may not be expected to detect all the obstacles without touching them, but should be able to maintain orientation and direction from one corner to the next while navigating among the scatter of obstacles.

            1. Students should first be able to turn toward and travel directly to a blank wall from 20 or 30 feet.

            2. If student is having trouble, it may help to position student about 5 feet away from the corner such that she is exactly facing the corner. Have her feel it with her cane. Then, ask her to turn and face "the right wall", then "the left wall" just as if turning her head to the panel or wall. It may also help to have students find the alcove first before finding a corner. She may wish to practice finding the opening to a large alcove, and traveling into and out of it.

      E. Tracking Course Boundaries: This involves being able to guide one's motion auditorily along borders and boundaries, such as walls, fences, a row of poles, lines of foliage, hallways, or aisleways in stores and parking lots. Start with solid, continuous surfaces before moving to sparse or intermittent features. Also, start with shorter distances before increasing distance. Distance may be increased to about 30 feet; wide corridors may be found in transit stations, airports, and suburban alley ways. When boundaries consist of clusters of elements, such as tables and chairs in a restaurant, individual elements of the path boundary may not be discernable, but these often cluster or aggregate to become detectable as a unit. For example, when winding one's way through a food court or restaurant, one may easily be able to thread one's way pretty gracefully among the furniture with minimal contact, without necessarily being able to distinguish or recognize any given piece. Encourage students to move at a moderate or brisk pace, as this will make this exercise easier. If they have trouble, it may help to use the radio pointed at the wall. It may also help to use the stimulus shift paradigm (VI-G) - placing the radio at the end of a long stretch of wall at the same distance that the student is to walk from the wall, such that the student walks directly toward the radio. Lower the volume over time so that the sonar takes over. Have student turn an exterior corner and maintain parallel distance. Some students may find it easier to travel straight down a corridor before paralleling a single wall. Also, it may help some students to do the centering exercise (see Viii-F).

      F. Centering: Here, students learn to center themselves between two surfaces. Find or arrange two more or less flat surfaces about 8 feet apart. The two surfaces should be approximately similar in nature. It is best if the two surfaces are in an otherwise open area. They could be tables stood on end, or parked cars, or trash bens, or a wide corridor, or easels holding large boards. (The surfaces don't necessarily need to be precisely flat, but they should be uniform to each other.) Situate student midway between the two surfaces, and explain that she is centered. Have her feel the equal distance with her cane. Then, disorient and re-situate with the student much closer to one side, and ask "which side are you closest to." (Young children often cannot answer this question when put this way, even when they know the answer. It often helps to ask "which side can you reach right out and touch?" Or, "go to the side you can touch the easiest or quickest.") Then, re-situate students so that they're near the center, but definitely not centered, and ask them to center themselves. They will often get close and say they are. It very often helps to then simply say, "You're close, but you're closer to one side than the other. Which one?" Nine time out of ten when asked this question, the students can state correctly which side they're closes to, and center themselves more closely. We don't expect exact centering right away. If they're within a few inches, we just tell them they're good. I don't push for "exact" centering until they've advanced considerably. Increase the distances between the two surfaces to about 50 feet apart. (For this, the surface should be large, like between two buildings.) If they really can't get it, then refresh using flat panels "which one's closer?" (see VI-C-4-a). It may also help to skip to the surfaces far apart first, then move to the closer ones.)

      G. Circling: The student should be able to walk in a circle around a large-ish object in either direction, and stop at the point of beginning. It doesn't need to be a circular object; it may be a minivan, large column, kiosk, a display case, a tree, or whatever. The object being traveled around should stand in otherwise pretty open space. Large objects should come first before smaller objects, such as poles or bushes. There should be some defining feature that indicates the starting point. It can be the presence of another object, such as a distant building, or it can be another noise, such as traffic sounds. A student might even be ask to use a compass or the sun, or the wind, or some unique characteristic in the ground. Otherwise, the space should be fairly open at first, but can be more congested later. Some beginning students may wander far and wide from the circle, not realizing they've lost it, because it fades gradually out of their perception. When a subtle stimulus fades gradually, one often doesn't realize it's fading until it's gone. Stabilizing attention often helps, here. We may ask, "Where's that (thing)?" Students can often reorient themselves quite well just by this question. They may need to stop, reorient, then continue.

IX. NEGOTIATING OBSTACLES:

      A. The traveler can learn to move among obstacles, maintaining goal directedness, with little or no physical contact with obstacles through body or cane. We generally start by approaching and avoiding a single, large, solid, stationary obstacle first, before advancing to smaller, sparser, possibly moving obstacles. We further advance to threading one's way among obstacles, while maintaining orientation. Obstacular environments may include department stores, furniture stores, parking lots, restaurants, classrooms, forests, or any cluttered space. Children may have the advantage here, because their reduced height makes everything around them perspectively larger and more detectable.

      B. Precision detection exercises can help to develop this skill. For example, have a student pass through a doorway on repeated occasions while slowly closing the door (thus narrowing the gap) with each trial. The student needs to determine the breadth of the opening, and ease through it without touching the sides. Also, having a student locate, reach for, and touch a pole without fishing for it can foster precision movement.

      C. An advanced form of this skill involves what we call agrogating one's surroundings. When threading one's way through dense patches of obstacles and maintaining one's goal directedness, one does not need to distinguish and identify every single obstacle in order to be able to go around it. One should learn to chunk or agrogate the obstacles in order to get better cues about alignment. This can improve tracking course boundaries, especially if the boundaries are comprised of disjointed features rather than a solid border. A group of 3 or 4 tables might become one line. A bush with a tree or bench might become another line. A sign with a planter box and a mail drop box might become a third line, and so on - or all can be followed as one long line. It is like mentally drawing a line connecting multiple points; one can't take a line very well with just one point. In this way, the student isn't overwhelmed or disoriented by each obstacle, or lost between obstacles.

X. IDENTIFICATION OF FEATURES AND ELEMENTS: All objects, features, and events in space are constructed of dimension (height, breadth), location (distance, laterality, elevation), and density (solid, sparse, absorption). (See IV.) We can use this language to help students describe what they are hearing. A pole, for instance, is tall, uniformly narrow, and solid. A bush is sparse, broader, and short. A tree is narrow and solid near the bottom, but becomes broad and sparse with increased elevation; its breadth and laterality increase. Stairs are solid and near toward the bottom, but get further away with elevation. Here is where stimulus association, clarification, and comparison can really help students to understand what they're hearing, and learn to register and describe subtler characteristics. The question, "what does this remind you of," (association) can often stimulate realization about an event being beheld. Sometimes densely pact foliage will register as solid, because of the strong reflection of acoustic energy, until it is directly compared with something solid.

XI. ENVIRONMENTAL LAYERING / SCENE ANALYSIS (we also call this gestalting): A student can learn to describe and image multiple events and layers of the environment. An example might be a bush in front of a wall, or a tree behind a fence, with a wall building behind that. The student should be encouraged to describe what she can hear most clearly, clarify that image, then concentrate on other elements. It's all in awareness of depth and distance cues, combined with distinctions in density. Distinctions in density may be likened to color contrast perception. Density distinctions can serve to make some objects really stand out from others. "What is close to you? What seems further away? How are they different?" Then, given what the student describes of the entire scene, what is their overall impression? "What is the picture? What are we looking at?" In our experience, more recently blinded people may be better at the imaging, the overall picture, even if their actual perceptions are more dull than students blind early in life. We believe this is because they have a lot of visual experience of the way scenes are arranged in the world. A long blinded person may be able to describe a scene quite accurately in terms of its characteristics, but still not be able to identify the object or scene the way one who has "seen it  all" can. Of course, blind kids who were free and encouraged to explore their environment prolifically can usually identify scenes quite well.

XII. DYNAMIC ENVIRONMENTAL INTERACTION (self orientation): Here, we put it all together. Ultimately, we want to foster students' ability to establish orientation and direct themselves through space. We move through the environment in a goal directed way, registering and processing all the elements.

      A. Street crossing: The student can learn to register elements part way or all the way across a street, and use this information as a kind of beacon to guide movement while crossing. It is like crossing to a wall, except that we are processing other stimuli (traffic) as well. The attention is NEVER taken away from the traffic; that must be the primary cue. But, sonar goal direction can be closely secondary. We start with quieter streets first, then move to noisy. Sonar and sound shadowing can also help to register quiet cars at rest, and warn against large quiet vehicles in motion. It isn't necessarily the complete answer to "what do we do with silent cars", but it can provide an additional layer of warning and protection.

      B. Crossing a parking lot: This is a combination of orienting toward an object (a far off building) and negotiating obstacles, both stationary and moving. Once we near the building, other features of the building can be determined to help us direct our course to the entrance. The entrance is often located in an alcove. Of course, there may also be other auditory cues suggestive of the entrance.

      C. Self Orientation: Students can learn to orient themselves to any new area. The exercise might go something like this:

            1. Choose a large, complex space - a park, school or college campus, transit station, playground, or shopping center.

            2. Establish a highly audible, distinctive point of reference, or point of departure. This is often a large alcove or corner where two buildings meet. It should be detectable from 50 feet away or so.

            3. The students practice leaving the point of reference, and locating three to five distinct elements of the environment. They should be distinctive from each other. Student may touch them for varification, but should identify them, or at least describe them first. The student should then return to the point of reference, then go back to locate and identify each of the elements they had found. Students should not just keep to pathways, but should be encouraged or even required (as part of the exercise) to cut across open space. (That's where the most fun is.) Objects might include distinctive trees or poles, park benches, trashcans, pavilions, fences, retaining walls, other buildings of unique character, steps, bushes or hedges and other plants, distinctive arrangements of objects, a particular vehicle in a nearby lot, etc. The student should be encouraged to repeat the exercise with larger numbers of elements or different elements - not more than 10, but the elements should be further and further from the point of reference. Ultimately, the student will establish other key points of reference relative to each other, and objects or features of smaller detail relative to those. Students may use other aids to help, such as a compass. The student may also make occasional use of public assistance if they've lost their bearings in returning to the reference point. Engagement of public assistance is an acceptible means of wayfinding. However, for sonar exercises, we encourage use of sonar as the primary means of information gathering and self direction. So, we ask that engagement of public assistance be kept to a minimum at first, until we find the sonar sense developing. Obviously, if the student continues to struggle with this advanced despite all instructional efforts, mutual engagement of public assistance can become the primary means of wayfinding for some students. This could even be a great GPS exercise where students practice mapping their environment. In fact, a very advanced student may create a tactile map of what they find. This process can be applied to orient oneself confidently and enjoyably to any type of space.

XIII. GROUP ACTIVITIES: Some of these exercises, particularly the last few, can be quite conducive to student groups. Students can help each other to register object characteristics and identify objects, image scenes and discuss what is perceived, and actively find their way around new spaces. The group energy often helps and encourages students to reach heights they might not otherwise reach. The group dynamic can serve as a tremendously motivating process. It's very interesting and powerful to observe a group of students come to consensus about what they perceive, and how best to find their way.

XIV. Self Exercises for Stimulating the Sonar Perception: Although these exercises are meant for those working with students to stimulate your own sonar sense, you can do any of these with your students as beginning exercises.

      A. Procure a large and small wide mouth container. Glass jars are good; seashells are excellent. Speak into the open air, then into each container. Note how the containers sound different from the open air, and from each other. Close your eyes, and have someone hold the containers in front of you as you speak. Try to hear when the container is in front of you, and which one is the smallest or largest. Have someone else speak, and, with eyes closed, you guess which container is which.

      B. Hold the mouths of the containers to your ear. What do you hear from them? Do you recall the "ocean in the seashell" phenomenon? It is only sound reflecting inside the container. Can you hear the difference between small and large containers? Put each container at each ear simultaneously. Can you hear how each sounds different? With your eyes closed, have someone present the containers randomly to each ear. Can you tell when the container is present or absent? Can you tell which container is which, large vs. small?

      C. Position yourself about a foot from a blank wall. Take a deep breath, and, with closed eyes, pivot your body while slowly exhaling in a "shshsh" sound. What happens to the "shshsh" sound as you turn your face away from the wall? How about toward the wall? While pivoting, try to hear when you are facing directly toward the wall. If the "shshsh" doesn't work for you, try an "aaaaaah" sound.

      D. Position yourself about 4 feet from the wall. Take a deep breath, and, with closed eyes, approach the wall while slowly exhaling a "shshsh" or suitable sound. Now, step away from the wall while exhaling. See if you can bring yourself to within 6 inches of the wall without touching it. How about 3 inches?

      E. Stand in the middle of a sparsely furnished room with your eyes closed, and turn slowly while exhaling the "shshsh" or suitable sound. See if you can locate the a corner. Begin walking, and see if you can find the corner.

      F. In a car find a residential street with several vehicles parked along it. (A parking lot will not do for this exercise.) Open the window, and, as you drive, listen carefully to the sound of the car every time you pass a parked vehicle. The sound fluctuates. If you can get someone else to drive, try this with closed eyes, and listen through the passenger window. The effect is more pronounced here. You may even be able to tell by listening whether the street is heavily lined with parked cars, or sparsely so.

      G. In an area familiar to you, try walking with a blindfold and long-cane. Try perceiving things around you by echoes. Do not try to ascertain exact locations of things, just strive for a sense of things flowing about you as you walk. Try clicking your tongue. Do you hear the shifting directions and distances of things as you move among them? Mobility instructors may find that doing this at least once or twice a week will help them in sonar training with students, and to comprehend their own cognitive process struggling to integrate nonvisual information for efficient travel. Your students do this all the time.

      H. Try accompanying your better students under a blindfold in an area familiar to you. Practice sonar navigation with them. Let them help you. They will love it, and you will both learn something.