The Mental Comparison of Distances in a Verbally Described Spatial Layout: Effects of Visual Deprivation (original) (raw)
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THE ROLE OF VISUAL EXPERIENCE IN KNOWLEDGE OF SPATIAL LAYOUT
1980
Adventitiously blinded. congenitally blind, and sighted adults made relative distance judgments in a familiar environment under three sets of instructions-neutral with respect to the metric of comparison, euclidean (straight-line distance between landmarks), and functional (walking distance between landmarks). Analysis of error scores and multidimensional scaling procedures indicated that, although there were no significant differences among groups under functional instructions, all three groups differed from one another under euclidean instructions. Specifically, the sighted group performed best and the congenitally blind group worst, with the adventitiously blind group in between. The results are discussed in the context of the role of visual experience in spatial representation and the application of these methods for evaluating orientation and mobility training for the blind.
Cognition, 2006
The purpose of the present study is twofold: the first objective is to evaluate the importance of visual experience for the ability to form a spatial representation (spatial mental model) of fairly elaborate spatial descriptions. Secondly, we examine whether blind people exhibit the same preferences (i.e. level of performance on spatial tasks) as sighted people in processing the type of perspective that is employed in a spatial description. Early blind, late blind and sighted participants listened to a route and a survey description of two environments. Next, they had to execute a recognition/priming task, a bird flight distance comparison task, and a scale model task. Spatial priming and symbolic distance effects were found for all participants. These findings suggest that early and late blind people can form spatial mental models on the basis of route and survey descriptions. Interestingly, in contrast with sighted people, blind people performed better after listening to a route than a survey description, even when the spatial problems that has to be solved explicitly favor the survey description. It seems that people with active vision build up a spatial mental model more efficiently from a survey description, while people with only visual memories (late blind), similar to people with no visual memories (early blind), build up a spatial mental model more efficiently from a route description.
Spatial representations in blind people: The role of strategies and mobility skills
The role of vision in the construction of spatial representations has been the object of numerous studies and heated debate. The core question of whether visual experience is necessary to form spatial representations has found different, often contradictory answers. The present paper examines mental images generated from verbal descriptions of spatial environments. Previous evidence had shown that blind individuals have difficulty remembering information about spatial environments. By testing a group of congenitally blind people, we replicated this result and found that it is also present when the overall mental model of the environment is assessed. This was not always the case, however, but appeared to correlate with some blind participants’ lower use of a mental imagery strategy and preference for a verbal rehearsal strategy, which was adopted particularly by blind people with more limited mobility skills. The more independent blind people who used a mental imagery strategy performed as well as sighted participants, suggesting that the difficulty blind people may have in processing spatial descriptions is not due to the absence of vision per se, but could be the consequence of both, their using less efficient verbal strategies and having poor mobility skills.
Allocentric and contra-aligned spatial representations of a town environment in blind people
Acta Psychologica, 2017
Evidence concerning the representation of space by blind individuals is still unclear, as sometimes blind people behave like sighted people do, while other times they present difficulties. A better understanding of blind people's difficulties, especially with reference to the strategies used to form the representation of the environment, may help to enhance knowledge of the consequences of the absence of vision. The present study examined the representation of the locations of landmarks of a real town by using pointing tasks that entailed either allocentric points of reference with mental rotations of different degrees, or contra-aligned representations. Results showed that, in general, people met difficulties when they had to point from a different perspective to aligned landmarks or from the original perspective to contra-aligned landmarks, but this difficulty was particularly evident for the blind. The examination of the strategies adopted to perform the tasks showed that only a small group of blind participants used a survey strategy and that this group had a better performance with respect to people who adopted route or verbal strategies. Implications for the comprehension of the consequences on spatial cognition of the absence of visual experience are discussed, focusing in particular on conceivable interventions. Highlights: • Blind and blindfolded sighted participants explored a tridimensional city map • They performed pointing tasks entailing allocentric and contra-aligned representations • Performance decreased with increasing mental rotations and contra-aligned representations • Differences between blind and sighted people were observed • Participants who used a survey strategy performed better
The aim of this research is to assess whether the crucial factor in determining the characteristics of blind people’s spatial mental images is concerned with the visual impairment per se or the processing style that the dominant perceptual modalities used to acquire spatial information impose, i.e. simultaneous (vision) vs sequential (kinaesthesis). Participants were asked to learn six positions in a large parking area via movement alone (congenitally blind, adventitiously blind, blindfolded sighted) or with vision plus movement (simultaneous sighted, sequential sighted), and then to mentally scan between positions in the path. The crucial manipulation concerned the sequential sighted group. Their visual exploration was made sequential by putting visual obstacles within the pathway in such a way that they could not see simultaneously the positions along the pathway. The results revealed a significant time\distance linear relation in all tested groups. However, the linear component was lower in sequential sighted and blind participants, especially congenital. Sequential sighted and congenitally blind participants showed an almost overlapping performance. Differences between groups became evident when mentally scanning farther distances (more than 5 m). This threshold effect could be revealing of processing limitations due to the need of integrating and updating spatial information. Overall, the results suggest that the characteristics of the processing style rather than the visual impairment per se affect blind people’s spatial mental images.
Hierarchical coding in the perception and memory of spatial layouts
Psychological Research, 2000
Two experiments were performed to investigate the organization of spatial information in perception and memory. Participants were confronted with map-like con®gurations of objects which were grouped by color (Experiment 1) or shape (Experiment 2) so as to induce cognitive clustering. Two tasks were administered: speeded veri®cation of spatial relations between objects and unspeeded estimation of the Euclidean distance between object pairs. In both experiments, veri®cation times, but not distance estimations, were aected by group membership. Spatial relations of objects belonging to the same color or shape group were veri®ed faster than those of objects from dierent groups, even if the spatial distance was identical. These results did not depend on whether judgments were based on perceptually available or memorized information, suggesting that perceptual, not memory processes were responsible for the formation of cognitive clusters.
Understanding spatial concepts at the geographic scale without the use of vision
In this article we review the literature that has sought to determine the spatial understanding of people with visual impairments or blindness. In particular, we examine the arguments surrounding whether people with visual impairments or blindness can understand geographic relationships such as distance, configuration and hierarchy. At present, the conclusions of researchers can be divided into three camps. One group suggests that vision is the spatial sense par excellence. This group suggests that congenitally blind individuals (blind from birth) are incapable of spatial thought because they have never experienced the perceptual processes (e.g., vision) necessary to comprehend spatial arrangements. Another group suggests that people with visual impairments can understand and mentally manipulate spatial concepts, but because information is based upon auditory and haptic cues this knowledge and comprehension is inferior to that based upon vision. The third group suggests that visually impaired individuals possess the same abilities to process and understand spatial concepts and that any differences, either in quantitative or qualitative terms, can be explained by intervening variables such as access to information, experience or stress. To date, most of the research which has led to these conclusions has been conducted using small-scale, laboratory environments and, as yet, we are still unsure as to how people with visual impairments and blindness learn, store and process spatial information at the geographic scale. We suggest that more research is needed to understand more fully the`mental landscapes' of people with blindness or visual impairments. Such research is necessary, particularly given the rapid growth of orientation and navigation aids in recent years aimed at increasing independent mobility. However, research must move out of the laboratory to examine spatial thought within the geographic environments that people with visual impairments or blindness interact with on a daily basis.
STRATEGIES FOR CONSTRUCTING SPATIAL REPRESENTATIONS USED BY BLIND AND SIGHTED SUBJECTS
The study was designed to investigate imagery strategies used by blind and sighted individuals and their ability to operate spatial representations. Performance accuracy in the imagery tasks was confirmed to be similar in the blind individuals with no visual memories and in the sighted subjects. On the other hand, the findings showed differences in preferred imagery strategies. The sighted, more often than the blind subjects, used the strategy of visualizing spatial matrices. The blind subjects applied a tapping strategy more often than the sighted ones. Additional analysis focused on the function of working memory systems in processing spatial stimuli by the blind and sighted subjects.
Geometric determinants of human spatial memory
Cognition, 2004
Geometric alterations to the boundaries of a virtual environment were used to investigate the representations underlying human spatial memory. Subjects encountered a cue object in a simple rectangular enclosure, with distant landmarks for orientation. After a brief delay, during which they were removed from the arena, subjects were returned to it at a new location and orientation and asked to mark the place where the cue had been. On some trials the geometry (size, aspect ratio) of the arena was varied between presentation and testing. Responses tended to lie somewhere between a location that maintained fixed distances from nearby walls and a location that maintained fixed ratios of the distances between opposing walls. The former were more common after expansions and for cued locations nearer to the edge while the latter were more common after contractions and for locations nearer to the center. The spatial distributions of responses predicted by various simple geometric models were compared to the data. The best fitting model was one derived from the response properties of 'place cells' in the rat hippocampus, which matches the 'proximities' 1=ðd þ cÞ of the cue to the four walls of the arena, where d is the distance to a wall and c is a global constant. Subjects also tended to adopt the same orientation at presentation and testing, although this was not due to using a view matching strategy, which could be ruled out in 50% of responses. Disoriented responses were most often seen where the cued location was near the center of the arena or where the long axis of a rectangular arena was changed between presentation and testing, suggesting that the geometry of the arena acts as a weak cue to orientation. Overall, the results suggest a process of visual landmark matching to determine orientation, combined with an abstract representation of the proximity of the cued location to the walls of the arena consistent with the neural representation of location in the hippocampus.