Michael Tlauka - Spatial skills in the visually impaired Flashcards Preview

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Flashcards in Michael Tlauka - Spatial skills in the visually impaired Deck (39):
1

What are the three types of blindness?

Congenitally blind - blind from birth (never had any visual experience).

Early blind - blind within the first few years of life.

Late blind - eye disease.

2

What is Congenitally blind?

blind from birth (never had any visual experience).

3

What is "Early Blind"

Blind within the first few years of life.

4

What is "late blind"?

Blind later in life e.g., due to eye disease.

5

What are the three main theories of the development of spatial skills among the blind?

Deficiency theory

Inefficiency theory

Difference theory

6

What is the Deficiency theory of the development of spatial skills among the blind?

That the congenitally blind have an incapacity to perform certain spatio-cognitive operations .

E.g., that they incapable of developing configurational knowledge (the highest level of spatial memory) e.g., where port Adelaide is relative to the air port (i.e., developing a cognitive map).

But the visually impaired can acquire knowledge via tactile, auditory, kin-aesthetic cues. and may be able to learn Route knowledge this way (associated decision with a landmark, e.g., turn left at lighthouse)

7

What is the Inefficiency theory of the development of spatial skills among the blind?

The information blind people have access to is not enough to be equivalent to sighted people - resulting in retarded spatial skills and limited potential to improve them.

8

What is the (quanitative) Difference theory of the development of spatial skills among the blind?

Assumes the normal range of spatio-cognitive behaviour and explains differences between the blind and the sighted population in terms of intervening variables such as access to information experience, stress and so on.

Visually impaired people can acquire spatial knowledge, however, the ways that they process information spatially is fundamentally different from their sighted counterparts.

9

Describe how the spatial knowledge of visually impaired people can be tested (3 ways)

Stimulus localisations - where is the sound coming from

Spatial Memory - recall layouts, way finding

Inferential abilities - Knowledge of spatial things that haven't been encountered yet e.g., a----b = b----c

10

What are the two types of haptic space?

Manipulation/reaching space

Locomotor space

11

Describe the Passini and Proulx (1988) study and findings (wayfinding - spatial memory)

Participants: Congenitally blind participants and a sighted control group.

Task: 2x guided architectural exploration of a large-scale building (very detailed); followed by 1x self-guide that Ps first outlined what they planned to do to reach the destination. Participants also verbalised their wayfinding on route. Then they had to build a model of the route they took of the building (cognitive map test). Finally, they answers a questionnaire identifying detours, propose shortcuts, give indications about the general form of the building and spatially situate the entrance of the building to the exit.

Results: The blind participants prepared their journey in more detail (58% more), paid attention to different elements of the journey (e.g., door frame for visually impaired) and made more decisions (76%) (and more variety of decisions) while walking (more cognitive effort) but were comparable at building a model of the building.

[Extra decisions came in the form of changing direction, changing levels, maintaining direction, finding architectural elements - for which the visually impaired experienced additional difficulty]


Conclusions: Visually imapired (congenitallly) can spatially record a relatively complex route he or she has previously learned ....Similar results (5-6/15 -> perfect model of route), but perhaps completed in a different way as suggested by the detail in the journey. Potential difference sin the way sighted and blind people recall and encode information. Sighted people used more visually accessible information (particularly signs) and visually impaired used more tactile and noise indicators - visually impaired used more information over all.

REJECTS deficiency theory
SUPPORTS quantitative different theory. (i.e., more information used and greater detail used reflects compensatory behaviours for not having access to distance cues rather than by a deficiency in spatio-cognitive abilities.)

12

Describe the Byrne and Salter (1982) study (spatial memory)

Participants: Congenitally blind participants and a sighted control group (wide age group) [matched]

Task: distance (e.g., what is the distance between here and the library) and direction (where is X e.g., carpark 4) estimates in an urban neighborhood (Realistic task). Half of the pairs contained the Ps home.

Results: Distance judgement (using ratio-scaling) - no difference between sighted and unsighted [though large individual difference] Similar performance between home and remote slopes, but slightly better performance when home was one of the points for visually impaired.

Directional judgement - the blind participants performed worse than the sighted participants. Sighted Ps equally good at estimating directions from home or else where. Blind subject worse when direction is from an imagined location (imagined viewpoint/start point), and worse than sighted for both home and elsewhere.

Conclusion:
two types of cognitive maps: network and vector maps
Network = absence of direction
Vector map = same information as a network map but + direction
Network = Train line map, Vector = driving car map

13

Describe the study by Riesar, Guth and Hill 1986

Study: sighted (blind-folded) adults, late-blinded adults, and early blinded adults

Task: participants learned the location of six targets - know where they are relevant to the start positions. Followed by three tasks (Counterbalanced)

1. Participants guided to one of the target locations and asked to point to X
2. Participants taken to an unvisited position (From start position) and asked to point to X
3. Did not move from start positions asked to "imagine being a X (4) and point to all the other locations though you were at X" - Much harder.

Results: *not sure*
- late blind and blindfolded had a hard time doing imagine task relative to being guided - benefited from being taken to visited or unvisited position.
- Early blind were equally poor in imagine and guidd (visited, unvisited)
Spatial-updating = cognitive map/spatial image is updated when you change position
Suggests that you need vision to know about spatial-updating

14

Describe the study by Ungar, Blades and Spencer (1997) (Hint: inferential abilities - unfamiliar environments)

Participants: Children between 5-11 years. A congenitally blind group, a residual vision group and a sighted group.

Task: participants studied a tactile map - a map you can touch. Rectangle 3 raised sports 1,2,3. Then taken to school yard "now at start position, this is 1, im now taking you to 2, now walk to 3. - look at the distance between 1-2 versus 2-3 (Ratio method)

Results:
In general sighted group performed better than visually impaired groups
SIGHTED KIDS USED RATION SCALED A-B = B-C IN distance
Visually impaired did not use. But when they told visually impaired kids that they could use ratio-scaling (taught them!) then they performed better
Innate strategies were different but visually impaired people can be trained to use ratio-scaling method

Conclusions: Implications for teaching map skills to children with visual impairment

15

What are some of the non-visual ways that can be used as environmental supports to assist the visually impaired in way finding?

Tactile Maps (introduction to new places and in familiar settings) [enhanced when tactile cues are combined with changes in the perceived elasticity and reverberation of the material]

Electronic guidance systems (verbal messages)



16

What factors improve wayfinding performance in the visually impaired?

Previous visual experience (i.e., not congenitally blind). Mobility courses, the number of times the subject is exposed to a given route.

17

Why is there reason to doubt the mental representation/cognitive map abilities of the visually impaired?

Mental representation/imagery is a quasi-perceptual experience. There is evidence to suggest that visual perception and mental imagery overlap both functionally (brain) and behavioural.

(Neuroimaging studies have shown that similar cortical areas support both visual perception and mental imagery)

If mental imagery is predicated on visual perception, then it begs the question: what is the nature of mental imagery in individuals who have never seen or have always had a reduced visual capacity?

18

How might mental representations/cognitive map abilities of the visually impaired be comparable to those of sighted individuals?

Evidence suggests that congenitally blind people are capable of generating mental imagery using mechanisms similar to those of sighted people (e.g., aleman et al., 2001)

Brain areas do not overlap entirely, visual cortical areas can be activated by objects presented in non-visual sensory modalities (For instance, touch) (Pietrinit et al., 2004)

The brain reorganises such that cortical areas originally devoted to processing visual information are recruited by other sensory modalities in the absence of visual experience (D'Angiulli and Waraich, 2002).


19

What is way finding?

A persons ability (cognitive and behavioural ) to reach destinations in the everyday environment. Defined in terms of spatial problems solving is a composite of three interrelated processes, decision making, decision executing and information processing.

[Decision making - that results in a plan of action or devision plan to reach a given destination
Decision executing - that transforms the plan into overt spatial behaviour and movement at the right place in space and
information processing - making up environmental perception and cognition that permits the above two decision -related processes to occur. Cognitive mapping is of course an integral part of information processing.]

20

How do blind people and sighted people differ on the spatial representations of distance and direction?

Blind = sighted in distances (similar error)
Blind people < sighted people - direction/bearings, particularly when the start-location is a distant (from local position) imagined one.

Suggests EGOCENTRIC orientation for visually impaired, use of self as a reference point

21

What conclusions can be drawn from the Byrne and Salter (1982) study (distances and direction in urban environment)?

Blindness selectively impairs one form of representation.

Two indecent representations of large-scale space are normally used (network and vector), but one can't be built properly if one is blind. or if one has a poor sense of direction.

1.. Vector- map contains geographical information in vector form, - formed by inspection of published maps, aerial photographs or from locomotor experience. BUT, extensive locomotor experience, in the absence of map use, may not be sufficient for development of vector-maps; for instance, life-time residents of a city may have no vector map information available about th details of its lay-out.

2. Network-map, encodes traversable routes as strings of nodes each with a corresponding to a location which is potentially a choice point but which need not correspond to a visually prominent landmark. At a node, an instruction may be store, such as "turn left" and if it is obeyed the nest node is reach. String may meet at nodes, forming a network in which "distance" corresponds only to the number of nodes along a pathway, and "direction" only to the changes of an arbitrary facing gearing (for instance, if the facing bearing is N, then "turn left" changes it to W; neither need correspond to true compass directions)

4. Clinical damage can impair either form of representation independently (Byrne, 1982).

5. Restricted experience of congenital blindness -> impoverish vector-maps compared with those of the sighted…then the results of the present experiment can be explained straightforwardly.

6. Subjects possess a network-map of routes to familiar locations, however, to estimate the direction of an out-ofsigh location at all accurately, a vector-map would be necessary.
7. Blind people, like those with a poor sense of direction, have to rely on an egocentric system of bearing, which is particularly a handicap when they are imagining themselves a t a remote locations from which the direction estimate is made.
8. whether this egocentric system is a precursor to a fully developed vector map, or an alternative system when a vector-map cannot develop is not known.


22

What is a vector map?

Vector- map contains geographical information in vector form, - formed by inspection of published maps, aerial photographs or from locomotor experience. BUT, extensive locomotor experience, in the absence of map use, may not be sufficient for development of vector-maps; for instance, life-time residents of a city may have no vector map information available about the details of its lay-out.

23

What is a network map?

Network-map, encodes traversable routes as strings of nodes each with a corresponding to a location which is potentially a choice point but which need not correspond to a visually prominent landmark. At a node, an instruction may be store, such as "turn left" and if it is obeyed the nest node is reach. String may meet at nodes, forming a network in which "distance" corresponds only to the number of nodes along a pathway, and "direction" only to the changes of an arbitrary facing gearing (for instance, if the facing bearing is N, then "turn left" changes it to W; neither need correspond to true compass directions)

24

What is "spatial updating"?

sensitivity to "changes in the structure of their perspectives" A persons ability to alter his or her ideas as to where objects in the environment are located, with respect to hi- or herself when moving among them. (being aware that when you move, the relative locations of objects from you changes)

A person may be able to develop a firm knowledge of where objects are located with respect to each other, and to the elf, and yet have difficulty in modifying that knowledge to take his or her own movements into account.

25

Outline the study by Hollins and Kelley (1988)

Ps. early-blind and blind-folded sighted peope.

Test:
Goal = to test early-blinds (compared to sighted) ability to spatially update in near space [to support similar findings in far locomotor space - explore generality of Rieser et a.'s 1982, 186, findings].

Task: learn (for later recall) to locations of small objects placed on a table


Experiment 1: can they remember the location of an object? and for how long?
Experiment 2: Does having them recall the position of another distractor object exerts any influence on the recalled position of an adjacent or previously learned object?
Experiment 3 and 4: dealt with 'updating' - the ability to examine objects from one location, then walk to a new location, and from there indicate the position of the objects. 3 = point to location of objects, 4 = reposition/replace objects

Results:
exp 1: Ps could recall the location an object had been for at least (And probably longer than) 24 minutes after last contact with the object. (therefore the length of experiment 3 and 4 was acceptable/feasible)

exp 2. no effect (e.g., interference, field effects etc.) of recalling position of distractor object on recall of target object's position. (therefore, multiple objects could be used in experiments 3/4)

(main experiments)
exp 3. blind = to blindfold-sighted when pointing from start position, both groups worse at pointing from new positions, but blind way way worse.

Exp. 4 Both blind and sighted had comparable performance, not worse in the replacing from different position.


MAJOR CONCLUSIONS:

The ability of early-blind people to take their own changed positions into account when recalling the position of previously examine objects depends on the type of behavioural response they are required to use. When asked to point to the locations of objects, the blind subjects had substantial difficulty in updating. When instructed to replace objects in their original positions on the table, the same blind subjects demonstrated a much greater degree of updating skill: accuracy was not significantly affected by whether they were still standing at their original station or had walked part of the way around the table before replacing the objects.

CONCLUSIONS:
More haptic experience in placing objects back into experience then in pointing. Allows Ps to correct faulty memory of the tables dimensions.

Systematic distortions occur while spatial information, derived from haptic examination of the table, is being encoded and committed to memory by the subjects - especially the blind subjects, but that little or no additional distortion occurs for either group during the subsequent cognitive operation of updating.

Distortions are memoric rather than perceptual.

i.e., participants DO NOT misjudge the position or direction they are facing, rather they misjudge the dimensions of the stimulus field.

[e.g., a distortion of the memory, with recalled distances fore-and-aft distances shrinking relative to side-to-side distances. - bias to err to the right of the location for both sighted and blind Ps, but moreso in blind.



26

Describe the study by Kalia, Legge, Roy, and Ogale (2010)

Ps: blind and sighted (blindfolded) ps.

Goal: to test if indoor route finding technology (and which of its settings) improved blind spatial navigation

Test: Baseline (no tech) compared with tech (using distance measure of feet, steps or seconds) to navigate routes in unfamiliar building.

Results:
PERFORMANCE
Blindfolded sight navigated better with tech. (less time needed)
Blind navigated better with tech, specifically, taking shorter routes, less bystander queries. BUT still required the same time (may be because they were older and needed more time to use the system)

DISTANCE MODE
no preference for blindfold-sighted. Preference for distance in steps for blind + performed better (fewer turns, shorter travel time) in steps mode than time or feet.

OTHER
Blind noted it was difficult to use allocentric referencing (north, south, east, west) and most mistakes were due to wrong turns - egocentric referecing may be preferable.

Conclusions: visual experience may improve understanding of metric distances (feet) and the visually impaired may benefit from being trained to use metric distance information.



Study investigating the best format for digital map + virtual speech software for blind navigation. "Building Navigator"


Wayfindings tech should provide 1. current location and heading of the individual 2. route to the destination. Routes consists of waypoints, locations where the navigator changes direction. Requires real time data about distance and direction to waypoints - until the destination is reached.


Blind people preferred distance given in steps…not feet or seconds (less good with metric measures than sited). Seemed to prefer egocentric reference over allocentric (north, south, east, west.

27

Can blind people compensate for their lack of visual experience?

(describe brain-based evidence that they do have mental imagery, and evidence that this imagery might use different inputs)

Yes.
Similar levels of performance can be achieved in imagery tasks by relying on different cognitive strategies: hence, in the absence of vision, congenitally blind individuals may rely more on verbal/semantic, haptic or purely spatial (i.e., without a visual content) representations.

blind individuals can compensate for their visual deficit by relying on experience in other sensory domains. In fact, it is likely that blind individuals compensate for the lack of vision both at a perceptual level, by enhancing their auditory capacities (Ro ̈der et al., 1999, 2000), and at a higher cognitive level, by developing conceptual networks with more acoustic and tactile nodes (Ro ̈ der and Ro ̈sler, 2003), thus contradicting the view that semantic networks are less elaborate in congenitally blind individuals (Pring, 1988)

______evidence____

Firstly, visual cortical areas serving visual imagery and those serving visual perception do not completely overlap (e.g., D’Esposito et al., 1997). Knauff et al. (2000) Secondly, visual cortical areas can be activated by objects presented in non-visual sensory modalities, as, for instance, touch (e.g. Pietrini et al., 2004). Thirdly, in presence of a severe visual deprivation, robust reorganization phenomena usually take place in the brain, so that cortical areas originally devoted to process visual information are largely recruited by other sensory modalities (e.g., D’Angiulli and Waraich, 2002). = These findings are consistent with the view that mental images are likely to be the end product of a series of constructive processes using different sources of information rather then mere copies of a perceptual input (e.g., Cornoldi et al., 1998).


There is ample evidence to indicate that the performance of blind individuals is remarkably similar to that of sighted individuals in tasks presumed to involve visual imagery. Similarly to normally sighted individuals, the blind tend to have a superior memory for concrete imageable words than for abstract words (e.g., Cornoldi et al., 1979). Furthermore, ‘‘imagery’’ instructions facilitate word retrieval in both the sighted and the blind (e.g., Cornoldi et al., 1989; Jonides et al., 1975). Yet, Blind individuals are not affected by the ‘‘visual-impedance-effect’’ (i.e. the interfering effect of the activation of irrelevant visual images on reasoning processes) (Knauff and Johnson-Laird, 2002), suggesting that they may rely predominantly on non-visual types of mental representations (Knauff and May, 2006). Similarly, verbally induced visual illusions in imagery are not found in congenitally blind people (Renier et al., 2006). = It seems that a strategy based on haptic imagery (i.e., mental representations generated on the basis of previous haptic experience) can be almost as accurate as a strategy based on visual imagery in many different cognitive tasks.

28


Deficiency versus quantitative difference theory, discuss (with evidence).

Verbal essay [just come up with some main points]

29

Blind people have poor spatial skills, discuss (With evidence).

Verbal essay [just come up with some main points]

30

If visual imagery and visual perception share common functional mechanisms --> what is the nature of mental imagery in individuals who have never seen/reduced visual capacity?

Verbal essay [just come up with some main points]

31

Why might point to an object from a new location be challenging for a congenitally blind person? (Compared to replacing objects)

[bonus: what is the author and year of this study?)

Pointing to an object from a new location is somewhat abstract - it requires simultaneous together vector image of the environment -- on the other hand replacing objects into a display allows the visually impaired to revisit haptic cues that better match the mental imagery that they have.

32

Why was poor judgement of distance found in visually impaired children but not adults?

Ratio scaling was used by adults and not innately by children - when taught ratio scaling, the children performed better.

33

What does a poor judgement of direction from an imagined position (for blind), but equivalent to sighted performance of distance judgement mean regarding the reference point of blind individuals?

Egocentric reference over allocentric reference system (Also supported by the preference for this form of reference system using assistance technology). May also suggest difficulties developing a cognitive map and updating ones location within it.

34

Why is it important to look at novel environments not just familiar ones? (in determining whether blind people are capable of creating cognitive maps)

Distance judgements were found to be similar amongst the blind and sighted in Passini and Proulx (1988), however, this tested distance judgements in familiar areas where

Studies in children performing tasks using novel environments are more suggestive of the innate strategies of the visually impaired (before addition strategies) and of their ability to produce a cognitive map (Ungur, Blades, and Spencer, 1997) how to they benefit from inferring from a tactile map the spatial properties of an unfamiliar location,. In particular, can the visually impaired translate distances on a tactile map to distances in the environment without visual experience?

35

Does the evidence support inefficiency or difference model of spatial skills in the visually impaired?


Performance of blind individuals in many behaviours and tasks requiring imagery can be inferior to that of sighted subjects; however, surprisingly often this is not the case. Where it IS and IS NOT the case, may reveal differences in the mental representations of space between blind and not-blind individuals. Evidence suggests different cognitive mechanisms and compensatory mechanisms that can overcome impairments. (Perceptual input affects the organisation of our mental processes)


(SUPPORT FOR QUALITATIVE DIFFERENCE MODEL OVER DEFICIENCY or INEFFICIENCY MODEL)

36

What is the nature of the cognitive function of mental imagery?

Neuroimaging studies suggest cortical areas support visual perception and imagery - but it is not complete overlap. Congenital total blindness have never received external visual stimulation - yet there is evidence to suggest that blind individuals do have mental imagery and that the mechanisms underlying this are similar to that normal-sighted people.

* Visual imagery -> network of spatial subsystems and higher-order visual areas..not directly by the primary visual cortex.
* Visual cortical areas can be activated by objects presented in non-visual sensory modalities e.g., TOUCH.
* Severe visual deprivation = reorganisation phenomena -> cortical areas originally devoted to process visual information are largely recruited by other sensory modalities.
* MENTAL IMAGES LIKELY THE END PRODUCT OF A SERIES OF CONSTRUCTIVE PROCESSES USING DIFFERENT SOURCES OF INFORMATION…not just mere copies of perceptual input.

* THUS, blind people can compensate for lack of visual perception when performing some spatial tasks

37

Name some ways the blind spatial perception may differ from that of sighted people.

Blind individuals may rely on different cognitive strategies e.g., more verbal/semantic, haptic or purely spatial (i.e., without visual content) representations.

Superior performance by the blind on auditory digit tasks, word span tests, long-term memory for voices and verbal material. Superior tactile ability and auditory localization (where, but not what)


* Blind individuals may be less efficient in tasks due to the sequential nature of haptic and auditory perception versus the simultaneous nature of vision….particularly when there are many items involve in the task i.e., blind do not develop efficient processes for simultaneously treating a large amount of information (processing limitation).

__________ STUDY EXAMPLE

(loomis et al. 1991) - a series of pictures had to be recognised either haptically or visually. In the haptic task, raised-line drawings had to be explore (either with one or two fingers) in the visual task, the same images were presented on a computer screen but they could be viewed only trough a stationary aperture at the centre of the display (With the size of the aperture simulating the use of either one or two fingertips). In this way, vision was "serialised" to resemble the haptic perceptual experience. The results showed that recognition in the serial visual task became as difficult of revision as it was for touch!!!

38

Describe (loomis et al. 1991) experiement....

(loomis et al. 1991) - a series of pictures had to be recognised either haptically or visually. In the haptic task, raised-line drawings had to be explore (either with one or two fingers) in the visual task, the same images were presented on a computer screen but they could be viewed only trough a stationary aperture at the centre of the display (With the size of the aperture simulating the use of either one or two fingertips). In this way, vision was "serialised" to resemble the haptic perceptual experience. The results showed that recognition in the serial visual task became as difficult of revision as it was for touch!!!


This suggests that part of the difficulty in spatial task in the visually impaired stems from the sequential/serial processing of information (A limitation)

39

How might blind people compensate?

Blind people may rely on non-visual types of mental representations e.g., haptic (touch) which can be as accurate as the visual strategies. Blind individuals can compensate for their visual deficit by relying on experience in other sensory domains - both at a perceptual level (enhanced auditory capacities) can at a higher cognitive level (developing conceptual networks with more acoustic and tactile nodes.)