An official website of the United States government
Walking in environments with stairs and curbs is potentially dangerous for people with low vision. We sought to understand what challenges low vision people face and what strategies and tools they use when navigating such surface level changes. Using contextual inquiry, we interviewed and observed 14 low vision participants as they completed navigation tasks in two buildings and through two city blocks. The tasks involved walking in- and outdoors, across four staircases and two city blocks. We found that surface level changes were a source of uncertainty and even fear for all participants. Besides the white cane that many participants did not want to use, participants did not use technology in the study. Participants mostly used their vision, which was exhausting and sometimes deceptive. Our findings highlight the need for systems that support surface level changes and other depth-perception tasks; they should consider low vision people's distinct experiences from blind people, their sensitivity to different lighting conditions, and leverage visual enhancements.
more »
« less
A paradigm for characterizing motion misperception in people with typical vision and low vision
SIGNIFICANCE Motion perception is an essential part of visual function. Understanding how people with low vision perceive motion can therefore inform rehabilitation strategies and assistive technology. Our study introduces the notion of Bayesian biases in motion perception and suggests that some people with low vision are susceptible to these systematic misperceptions. PURPOSEWe aimed to develop a paradigm that can efficiently characterize motion percepts in people with low vision and compare their responses with well-known misperceptions made by people with typical vision when targets are hard to see. METHODSWe recruited a small cohort of individuals with reduced acuity and contrast sensitivity (n = 5) as well as a comparison cohort with typical vision (n = 5) to complete a psychophysical study. Study participants were asked to judge the motion direction of a tilted rhombus that was either high or low contrast. In a series of trials, the rhombus oscillated vertically, horizontally, or diagonally. Participants indicated the perceived motion direction using a number wheel with 12 possible directions, and statistical tests were used to examine response biases. RESULTSAll participants with typical vision showed systematic misperceptions well predicted by a Bayesian inference model. Specifically, their perception of vertical or horizontal motion was biased toward directions orthogonal to the long axis of the rhombus. They had larger biases for hard-to-see (low contrast) stimuli. Two participants with low vision had a similar bias, but with no difference between high- and low-contrast stimuli. The other participants with low vision were unbiased in their percepts or biased in the opposite direction. CONCLUSIONSOur results suggest that some people with low vision may misperceive motion in a systematic way similar to people with typical vision. However, we observed large individual differences. Future work will aim to uncover reasons for such differences and identify aspects of vision that predict susceptibility.
more »
« less
- Award ID(s):
- 2041726
- PAR ID:
- 10568295
- Publisher / Repository:
- Optometry and Vision Science
- Date Published:
- Journal Name:
- Optometry and Vision Science
- Volume:
- 101
- Issue:
- 5
- ISSN:
- 1040-5488
- Page Range / eLocation ID:
- 252 to 262
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Abstract Hand position can be estimated by vision and proprioception (position sense). The brain is thought to weight and integrate these percepts to form a multisensory estimate of hand position with which to guide movement. Force field adaptation, a type of cerebellum-dependent motor learning, is associated with both motor and proprioceptive changes. The cerebellum has connections with multisensory parietal regions; however, it is unknown if force adaptation is associated with changes in multisensory perception. If force adaptation affects all relevant sensory modalities similarly, the brain’s weighting of vision vs. proprioception should be maintained. Alternatively, if force perturbation is interpreted as somatosensory unreliability, vision may be up-weighted relative to proprioception. We assessed visuo-proprioceptive weighting with a perceptual estimation task before and after subjects performed straight-ahead reaches grasping a robotic manipulandum. Each subject performed one session with a clockwise or counter-clockwise velocity-dependent force field, and one session in a null field. Subjects increased their weight of vision vs. proprioception in the force field session relative to the null session, regardless of force field direction, in the straight-ahead dimension (F1,44 = 5.13, p = 0.029). This suggests that force field adaptation is associated with an increase in the brain’s weighting of vision vs. proprioception.more » « less
-
Groups, teams, and collectives —people—are incredibly important to human behavior. People live in families, work in teams, and celebrate and mourn together in groups. Despite the huge variety of human group activity and its fundamental importance to human life, social-psychological research on person perception has overwhelmingly focused on its namesake, the person, rather than expanding to consider people perception. By looking to two unexpected partners, the vision sciences and organization behavior, we find emerging work that presents a path forward, building a foundation for understanding how people perceive other people. And yet this nascent field is missing critical insights that scholars of social vision might offer: specifically, for example, the chance to connect perception to behavior through the mediators of cognition and motivational processes. Here, we review emerging work across the vision and social sciences to extract core principles of people perception: efficiency, capacity, and complexity. We then consider complexity in more detail, focusing on how people perception modifies person-perception processes and enables the perception of group emergent properties as well as group dynamics. Finally, we use these principles to discuss findings and outline areas fruitful for future work. We hope that fellow scholars take up this people-perception call.more » « less
-
Abstract Selective attention improves sensory processing of relevant information but can also impact the quality of perception. For example, attention increases visual discrimination performance and at the same time boosts apparent stimulus contrast of attended relative to unattended stimuli. Can attention also lead to perceptual distortions of visual representations? Optimal tuning accounts of attention suggest that processing is biased towards “off-tuned” features to maximize the signal-to-noise ratio in favor of the target, especially when targets and distractors are confusable. Here, we tested whether such tuning gives rise to phenomenological changes of visual features. We instructed participants to select a color among other colors in a visual search display and subsequently asked them to judge the appearance of the target color in a 2-alternative forced choice task. Participants consistently judged the target color to appear more dissimilar from the distractor color in feature space. Critically, the magnitude of these perceptual biases varied systematically with the similarity between target and distractor colors during search, indicating that attentional tuning quickly adapts to current task demands. In control experiments we rule out possible non-attentional explanations such as color contrast or memory effects. Overall, our results demonstrate that selective attention warps the representational geometry of color space, resulting in profound perceptual changes across large swaths of feature space. Broadly, these results indicate that efficient attentional selection can come at a perceptual cost by distorting our sensory experience.more » « less
-
Despite significant vision loss, humans can still recognize various emotional stimuli via a sense of hearing and express diverse emotional responses, which can be sorted into two dimensions, arousal and valence. Yet, many research studies have been focusing on sighted people, leading to lack of knowledge about emotion perception mechanisms of people with visual impairment. This study aims at advancing knowledge of the degree to which people with visual impairment perceive various emotions – high/low arousal and positive/negative emotions. A total of 30 individuals with visual impairment participated in interviews where they listened to stories of people who became visually impaired, encountered and overcame various challenges, and they were instructed to share their emotions. Participants perceived different kinds and intensities of emotions, depending on their demographic variables such as living alone, loneliness, onset of visual impairment, visual acuity, race/ethnicity, and employment status. The advanced knowledge of emotion perceptions in people with visual impairment is anticipated to contribute toward better designing social supports that can adequately accommodate those with visual impairment.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1097/OPX.0000000000002139
