scholarly journals Knowledge of animal appearance among sighted and blind adults

2019 ◽  
Vol 116 (23) ◽  
pp. 11213-11222 ◽  
Author(s):  
Judy S. Kim ◽  
Giulia V. Elli ◽  
Marina Bedny

How does first-person sensory experience contribute to knowledge? Contrary to the suppositions of early empiricist philosophers, people who are born blind know about phenomena that cannot be perceived directly, such as color and light. Exactly what is learned and how remains an open question. We compared knowledge of animal appearance across congenitally blind (n = 20) and sighted individuals (two groups, n = 20 and n = 35) using a battery of tasks, including ordering (size and height), sorting (shape, skin texture, and color), odd-one-out (shape), and feature choice (texture). On all tested dimensions apart from color, sighted and blind individuals showed substantial albeit imperfect agreement, suggesting that linguistic communication and visual perception convey partially redundant appearance information. To test the hypothesis that blind individuals learn about appearance primarily by remembering sighted people’s descriptions of what they see (e.g., “elephants are gray”), we measured verbalizability of animal shape, texture, and color in the sighted. Contrary to the learn-from-description hypothesis, blind and sighted groups disagreed most about the appearance dimension that was easiest for sighted people to verbalize: color. Analysis of disagreement patterns across all tasks suggest that blind individuals infer physical features from non-appearance properties of animals such as folk taxonomy and habitat (e.g., bats are textured like mammals but shaped like birds). These findings suggest that in the absence of sensory access, structured appearance knowledge is acquired through inference from ontological kind.

2019 ◽  
Author(s):  
Judy Sein Kim ◽  
Giulia V Elli ◽  
Marina Bedny

How does first-person sensory experience contribute to knowledge? Contrary to the suppositions of empiricist philosophers, people who are blind know about phenomena that cannot be perceived directly, such as color and light. Do blind individuals learn about appearance primarily by remembering sighted people’s descriptions of what they see (e.g. “elephants are grey”)? How is “verbally-acquired” knowledge about perception represented? We compared knowledge of animal appearance across congenitally blind (n=20) and sighted individuals (two groups, n=20 and n=35). Participants performed a battery of tasks, including ordering animals by size and height and sorting by shape, skin texture, and color (animal names presented in Braille or print). If people who are blind learn primarily from verbal description, blind and sighted groups should share less knowledge about perceptual dimensions that are more difficult to verbalize. We quantified verbalizability by applying the Simpson’s Diversity Index to participant labels of shape, texture and color sorting piles. Disagreement across groups was apparent for all dimensions tested, suggesting that visual perception and language convey partially non-redundant information. Contrary to the idea that blind individuals learn primarily from verbal descriptions, blind and sighted groups disagreed most on the dimension that was easiest to verbalize: animal color. Analysis of disagreement patterns suggests that blind individuals infer physical features from other animal properties, such as folk taxonomy and habitat (e.g. bats are shaped like birds but textured like mammals). In the absence of sensory access, structured appearance knowledge is acquired through inference.


2020 ◽  
Author(s):  
Judy Sein Kim ◽  
Brianna Aheimer ◽  
Veronica Montane Manrara ◽  
Marina Bedny

Empiricist philosophers such as Locke famously argued that people born blind could only acquire shallow, fragmented facts about color. Contrary to this intuition, we report that blind and sighted people share an in-depth understanding of color, despite disagreeing about arbitrary color facts. Relative to the sighted, blind individuals are less likely to generate ‘yellow’ for banana and ‘red’ for stop-sign. However, blind and sighted adults are equally likely to infer that two bananas (natural kinds) and two stop-signs (artifacts with functional colors) are more likely to have the same color than two cars (artifacts with non-functional colors), make similar inferences about novel objects’ colors, and provide similar causal explanations. We argue that people develop inferentially-rich and intuitive “theories” of color regardless of visual experience. Linguistic communication is more effective at aligning people’s theories than their knowledge of verbal facts.


2021 ◽  
Author(s):  
Mengyu Tian ◽  
Elizabeth J. Saccone ◽  
Judy S. Kim ◽  
Shipra Kanjlia ◽  
Marina Bedny

The neural basis of reading is highly consistent across a variety of languages and visual scripts. An unanswered question is whether the sensory modality of symbols influences the neural basis of reading. According to the modality-invariant view, reading depends on the same neural mechanisms regardless of the sensory input modality. Consistent with this idea, previous studies find that the visual word form area (VWFA) within the ventral occipitotemporal cortex (vOTC) is active when blind individuals read Braille by touch. However, connectivity-based theories of brain function suggest that the neural entry point of written symbols (touch vs. vision) may influence the neural architecture of reading. We compared the neural basis of the visual print (sighted n=15) and tactile Braille (congenitally blind n=19) in proficient readers using analogous reading and listening tasks. Written stimuli varied in word-likeness from real words to consonant strings and non-letter shape strings. Auditory stimuli consisted of words and backward speech sounds. Consistent with prior work, vOTC was active during Braille and visual reading. However, in sighted readers, visual print elicited a posterior/anterior vOTC word-form gradient: anterior vOTC preferred larger orthographic units (words), middle vOTC preferring consonant strings, and posterior vOTC responded to shapes (i.e., lower-level physical features). No such gradient was observed in blind readers of Braille. Consistent with connectivity predictions, in blind Braille readers, posterior parietal cortices (PPC) and parieto-occipital areas were recruited to a greater degree and PPC contained word-preferring patches. Lateralization of Braille in blind readers was predicted by laterality of spoken language, as well as by reading hand. These results suggested that the neural basis of reading is influenced by symbol modality and support connectivity-based views of cortical function.


2015 ◽  
Vol 27 (8) ◽  
pp. 1633-1647 ◽  
Author(s):  
Ben Deen ◽  
Rebecca Saxe ◽  
Marina Bedny

In congenital blindness, the occipital cortex responds to a range of nonvisual inputs, including tactile, auditory, and linguistic stimuli. Are these changes in functional responses to stimuli accompanied by altered interactions with nonvisual functional networks? To answer this question, we introduce a data-driven method that searches across cortex for functional connectivity differences across groups. Replicating prior work, we find increased fronto-occipital functional connectivity in congenitally blind relative to blindfolded sighted participants. We demonstrate that this heightened connectivity extends over most of occipital cortex but is specific to a subset of regions in the inferior, dorsal, and medial frontal lobe. To assess the functional profile of these frontal areas, we used an n-back working memory task and a sentence comprehension task. We find that, among prefrontal areas with overconnectivity to occipital cortex, one left inferior frontal region responds to language over music. By contrast, the majority of these regions responded to working memory load but not language. These results suggest that in blindness occipital cortex interacts more with working memory systems and raise new questions about the function and mechanism of occipital plasticity.


2015 ◽  
Vol 7 (1) ◽  
pp. 37-58 ◽  
Author(s):  
Victor R. Schinazi ◽  
Tyler Thrash ◽  
Daniel-Robert Chebat

2018 ◽  
Author(s):  
Theo Marins ◽  
Maite Russo ◽  
Erika Rodrigues ◽  
jorge Moll ◽  
Daniel Felix ◽  
...  

ABSTRACTEvidence of cross-modal plasticity in blind individuals has been reported over the past decades showing that non-visual information is carried and processed by classical “visual” brain structures. This feature of the blind brain makes it a pivotal model to explore the limits and mechanisms of brain plasticity. However, despite recent efforts, the structural underpinnings that could explain cross-modal plasticity in congenitally blind individuals remain unclear. Using advanced neuroimaging techniques, we mapped the thalamocortical connectivity and assessed cortical thickness and integrity of white matter of congenitally blind individuals and sighted controls to test the hypothesis that aberrant thalamocortical pattern of connectivity can pave the way for cross-modal plasticity. We described a direct occipital takeover by the temporal projections from the thalamus, which would carry non-visual information (e.g. auditory) to the visual cortex in congenitally blinds. In addition, the amount of thalamo-occipital connectivity correlated with the cortical thickness of primary visual cortex (V1), supporting a probably common (or related) reorganization phenomena. Our results suggest that aberrant thalamocortical connectivity as one possible mechanism of cross-modal plasticity in blinds, with potential impact on cortical thickness of V1.SIGNIFICANT STATEMENTCongenitally blind individuals often develop greater abilities on spared sensory modalities, such as increased acuity in auditory discrimination and voice recognition, when compared to sighted controls. These functional gains have been shown to rely on ‘visual’ cortical areas of the blind brain, characterizing the phenomenon of cross-modal plasticity. However, its anatomical underpinnings in humans have been unsuccessfully pursued for decades. Recent advances of non-invasive neuroimaging techniques allowed us to test the hypothesis of abnormal thalamocortical connectivity in congenitally blinds. Our results showed an expansion of the thalamic connections to the temporal cortex over those that project to the occipital cortex, which may explain, the cross-talk between the visual and auditory systems in congenitally blind individuals.


2018 ◽  
Vol 29 (7) ◽  
pp. 2859-2875 ◽  
Author(s):  
A W de Borst ◽  
B de Gelder

Abstract Cortical plasticity in congenitally blind individuals leads to cross-modal activation of the visual cortex and may lead to superior perceptual processing in the intact sensory domains. Although mental imagery is often defined as a quasi-perceptual experience, it is unknown whether it follows similar cortical reorganization as perception in blind individuals. In this study, we show that auditory versus tactile perception evokes similar intra-modal discriminative patterns in congenitally blind compared with sighted participants. These results indicate that cortical plasticity following visual deprivation does not influence broad intra-modal organization of auditory and tactile perception as measured by our task. Furthermore, not only the blind, but also the sighted participants showed cross-modal discriminative patterns for perception modality in the visual cortex. During mental imagery, both groups showed similar decoding accuracies for imagery modality in the intra-modal primary sensory cortices. However, no cross-modal discriminative information for imagery modality was found in early visual cortex of blind participants, in contrast to the sighted participants. We did find evidence of cross-modal activation of higher visual areas in blind participants, including the representation of specific-imagined auditory features in visual area V4.


1980 ◽  
Vol 74 (9) ◽  
pp. 333-337 ◽  
Author(s):  
Robert Lambert ◽  
Malcolm West

This article discusses the effect on congenitally blind children of three types of parents: those who are over-protective, those who push the child toward independence too soon, and those who are “good enough.” The authors focus on how the three styles of parenting affect the blind child's ability to give and receive and develop a sense of competence. These effects are discussed in the context of the ego ideal. The authors also examine the depressive core that is often the result of the blind child's inability to live up to the dictates of the ego ideal. Finally, they suggest a fourth style of parenting that would prepare blind children better for the problems they will encounter in the sighted world.


2020 ◽  
Author(s):  
Simona Manescu ◽  
Christine Chouinard-Leclaire ◽  
Olivier Collignon ◽  
Franco Lepore ◽  
Johannes Frasnelli

Abstract Although often considered a nondominant sense for spatial perception, chemosensory perception can be used to localize the source of an event and potentially help us navigate through our environment. Would blind people who lack the dominant spatial sense—vision—develop enhanced spatial chemosensation or suffer from the lack of visual calibration on spatial chemosensory perception? To investigate this question, we tested odorant localization abilities across nostrils in blind people compared to sighted controls and if the time of vision loss onset modulates those abilities. We observed that congenitally blind individuals (10 subjects) outperformed sighted (20 subjects) and late-blind subjects (10 subjects) in a birhinal localization task using mixed olfactory-trigeminal stimuli. This advantage in congenitally blind people was selective to olfactory localization but not observed for odorant detection or identification. We, therefore, showed that congenital blindness but not blindness acquired late in life is linked to enhanced localization of chemosensory stimuli across nostrils, most probably of the trigeminal component. In addition to previous studies highlighting enhanced localization abilities in auditory and tactile modalities, our current results extend such enhanced abilities to chemosensory localization.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Birgitta Dresp-Langley

Generic properties of curvature representations formed on the basis of vision and touch were examined as a function of mathematical properties of curved objects. Virtual representations of the curves were shown on a computer screen for visual scaling by sighted observers (experiment 1). Their physical counterparts were placed in the two hands of blindfolded and congenitally blind observers for tactile scaling. The psychophysical data show that curvature representations in congenitally blind individuals, who never had any visual experience, and in sighted observers, who rely on vision most of the time, are statistically linked to the same mathematical properties of the curves. The perceived magnitude of object curvature, sensed through either vision or touch, is related by a mathematical power law, with similar exponents for the two sensory modalities, to the aspect ratio of the curves, a scale invariant geometric property. This finding supports biologically motivated models of sensory integration suggesting a universal power law for the adaptive brain control and balance of motor responses to environmental stimuli from any sensory modality.


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