There's more to "sparkle" than meets the eye: Knowledge of vision and light verbs among congenitally blind and sighted individuals.

We examined the contribution of first-person sensory experience to concepts by comparing the meanings of perception (visual/tactile) and emission (light/sound) verbs among congenitally blind (N = 25) and sighted speakers (N = 22). Participants judged semantic similarity for pairs of verbs referring to events of visual (e.g. to peek), tactile (e.g. to feel) and amodal perception (e.g. to perceive) as well as light (e.g. to shimmer) and sound (e.g. to boom) emission and manner of motion (to roll) (total word pairs, N = 2041). Relative to the sighted, blind speakers had higher agreement among themselves on touch perception and sound emission verbs. However, for visual verbs, the judgments of blind and sighted participants were indistinguishable, both in the semantic criteria used and subject-wise variability. Blind and sighted individuals alike differentiate visual perception verbs from verbs of touch and amodal perception and differentiate among acts of visual perception e.g. intense/continuous from brief acts of looking (e.g. peek vs. stare). Light emission verbs are differentiated according to intensity (blaze vs. glow) and stability (blaze vs. flash). Thus detailed knowledge of visual word meanings is acquired without first-person sensory access.

Neural correlates associated with superior tactile symmetry perception in the early blind.

Symmetry is an organizational principle that is ubiquitous throughout the visual world. However, this property can also be detected through non-visual modalities such as touch. The role of prior visual experience on detecting tactile patterns containing symmetry remains unclear. We compared the behavioral performance of early blind and sighted (blindfolded) controls on a tactile symmetry detection task. The tactile patterns used were similar in design and complexity as in previous visual perceptual studies. The neural correlates associated with this behavioral task were identified with functional magnetic resonance imaging (fMRI). In line with growing evidence demonstrating enhanced tactile processing abilities in the blind, we found that early blind individuals showed significantly superior performance in detecting tactile symmetric patterns compared to sighted controls. Furthermore, comparing patterns of activation between these two groups identified common areas of activation (e.g. superior parietal cortex) but key differences also emerged. In particular, tactile symmetry detection in the early blind was also associated with activation that included peri-calcarine cortex, lateral occipital (LO), and middle temporal (MT) cortex, as well as inferior temporal and fusiform cortex. These results contribute to the growing evidence supporting superior behavioral abilities in the blind, and the neural correlates associated with crossmodal neuroplasticity following visual deprivation.

Perception of tactile graphics: embossings versus cutouts.

Graphical information, such as illustrations, graphs, and diagrams, are an essential complement to text for conveying knowledge about the world. Although graphics can be communicated well via the visual modality, conveying this information via touch has proven to be challenging. The lack of easily comprehensible tactile graphics poses a problem for the blind. In this paper, we advance a hypothesis for the limited effectiveness of tactile graphics. The hypothesis contends that conventional graphics that rely upon embossings on two-dimensional surfaces do not allow the deployment of tactile exploratory procedures that are crucial for assessing global shape. Besides potentially accounting for some of the shortcomings of current approaches, this hypothesis also serves a prescriptive purpose by suggesting a different strategy for conveying graphical information via touch, one based on cutouts. We describe experiments demonstrating the greater effectiveness of this approach for conveying shape and identity information. These results hold the potential for creating more comprehensible tactile drawings for the visually impaired while also providing insights into shape estimation processes in the tactile modality.

Development of an audio-based virtual gaming environment to assist with navigation skills in the blind.

Audio-based Environment Simulator (AbES) is virtual environment software designed to improve real world navigation skills in the blind. Using only audio based cues and set within the context of a video game metaphor, users gather relevant spatial information regarding a building's layout. This allows the user to develop an accurate spatial cognitive map of a large-scale three-dimensional space that can be manipulated for the purposes of a real indoor navigation task. After game play, participants are then assessed on their ability to navigate within the target physical building represented in the game. Preliminary results suggest that early blind users were able to acquire relevant information regarding the spatial layout of a previously unfamiliar building as indexed by their performance on a series of navigation tasks. These tasks included path finding through the virtual and physical building, as well as a series of drop off tasks. We find that the immersive and highly interactive nature of the AbES software appears to greatly engage the blind user to actively explore the virtual environment. Applications of this approach may extend to larger populations of visually impaired individuals.