scholarly journals The size-weight illusion is unimpaired in individuals with a history of congenital visual deprivation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rashi Pant ◽  
Maria J. S. Guerreiro ◽  
Pia Ley ◽  
Davide Bottari ◽  
Idris Shareef ◽  
...  

AbstractVisual deprivation in childhood can lead to lifelong impairments in multisensory processing. Here, the Size-Weight Illusion (SWI) was used to test whether visuo-haptic integration recovers after early visual deprivation. Normally sighted individuals perceive larger objects to be lighter than smaller objects of the same weight. In Experiment 1, individuals treated for dense bilateral congenital cataracts (who had no patterned visual experience at birth), individuals treated for developmental cataracts (who had patterned visual experience at birth, but were visually impaired), congenitally blind individuals and normally sighted individuals had to rate the weight of manually explored cubes that differed in size (Small, Medium, Large) across two possible weights (350 g, 700 g). In Experiment 2, individuals treated for dense bilateral congenital cataracts were compared to sighted individuals in a similar task using a string set-up, which removed haptic size cues. In both experiments, indistinguishable SWI effects were observed across all groups. These results provide evidence that early aberrant vision does not interfere with the development of the SWI, and suggest a recovery of the integration of size and weight cues provided by the visual and haptic modality.

2021 ◽  
Author(s):  
Rashi Pant ◽  
Maria J. S. Guerreiro ◽  
Pia Ley ◽  
Davide Bottari ◽  
Idris Shareef ◽  
...  

AbstractVisual deprivation in childhood can lead to lifelong impairments in visual and multisensory processing. Here, the Size-Weight-Illusion was used to test whether visuo-haptic integration recovers after sight restoration. In Experiment 1, congenital (CC: 7 (3F), 8–35 years) and developmental cataract reversal individuals (DC: 9 (2F), 8–37 years), as well as congenitally blind (CB: 2 (1F), 33 and 44 years) and normally sighted individuals (SC: 10 (7F), 19-36 years) perceived larger objects as lighter than smaller objects of the same weight. In Experiment 2, CC (6 (1F), 17–44.7 years) and SC (7 (5F), 21-29 years) individuals performed identically when tested without haptic size cues. Together, this suggested that early visual experience is not necessary to perceive the Size-Weight-Illusion.


Perception ◽  
1989 ◽  
Vol 18 (3) ◽  
pp. 379-389 ◽  
Author(s):  
Morton A Heller

Two experiments are reported on the contribution of visual experience to tactile perception. In the first experiment, sighted, congenitally blind, and late blind individuals made tactual matches to tangible embossed shapes. In the second experiment, the same subjects attempted tactile identification of raised-line drawings. The three groups did not differ in the accuracy of shape matching, but both groups of blind subjects were much faster than the sighted. Late blind observers were far better than the sighted or congenitally blind at tactile picture identification. Four of the twelve pictures were correctly identified by most of the late blind subjects. The sighted and congenitally blind performed at comparable levels in picture naming. There was no evidence that visual experience alone aided the sighted in the tactile task under investigation, since they performed no better than did the early blind. The superiority of the late blind suggests that visual exposure to drawings and the rules of pictorial representation may help tactile picture identification when combined with a history of tactual experience.


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):  
Elena Nava ◽  
Luigi Tamè ◽  
Serena Giurgola ◽  
Nadia Bolognini

Abstract Neuropsychological reports of phantom sensations in congenital limb aplasia have often been taken as evidence of the existence of an innate, ‘hard-wired’, representation of the body in the brain that does not need to be constructed from, or updated by, online afferent sensory inputs, including vision. However, when asked to draw the contour of their own body and of an ideal body (i.e. body with perfect proportions), congenitally, but not late blind individuals, exhibited a magnified representation of their own body, specifically of their hands, in comparison to sighted controls. This over-representation did not extend to their ideal body model. These findings show that the representation of the own body metric is shaped by early visual experience, and that seeing one’s own and other bodies early in development contributes to the construction of a unified internal model, in which ‘own’ and ‘other’ merge.


Author(s):  
Kornelia Czerwińska ◽  
Agnieszka Piskorska

The paper argues that gaps in knowledge attested in congenitally blind individuals may negatively affect their performance in foreign language tasks testing reading comprehension. Characteristics of a blind learner at various stages of cognitive and educational development are presented, with focus on gaps in knowledge resulting from sight impairment. The concept of pragmatic competence is first explained generally in reference to communication and then it is applied to a case of a comprehension task taken from an EFL exam (Polish “matura”, basic level). An analysis of the text indicates that despite being relatively simple in linguistic terms, comprehension tasks may pose a significant processing challenge to blind students due to a large amount of implicitly communicated information dependent on visual experience.


2020 ◽  
Vol 117 (37) ◽  
pp. 23011-23020 ◽  
Author(s):  
N. Apurva Ratan Murty ◽  
Santani Teng ◽  
David Beeler ◽  
Anna Mynick ◽  
Aude Oliva ◽  
...  

The fusiform face area responds selectively to faces and is causally involved in face perception. How does face-selectivity in the fusiform arise in development, and why does it develop so systematically in the same location across individuals? Preferential cortical responses to faces develop early in infancy, yet evidence is conflicting on the central question of whether visual experience with faces is necessary. Here, we revisit this question by scanning congenitally blind individuals with fMRI while they haptically explored 3D-printed faces and other stimuli. We found robust face-selective responses in the lateral fusiform gyrus of individual blind participants during haptic exploration of stimuli, indicating that neither visual experience with faces nor fovea-biased inputs is necessary for face-selectivity to arise in the lateral fusiform gyrus. Our results instead suggest a role for long-range connectivity in specifying the location of face-selectivity in the human brain.


2017 ◽  
Author(s):  
Virginie Crollen ◽  
Latifa Lazzouni ◽  
Mohamed Rezk ◽  
Antoine Bellemare ◽  
Franco Lepore ◽  
...  

AbstractLocalizing touch relies on the activation of skin-based and externally defined spatial frames of references. Psychophysical studies have demonstrated that early visual deprivation prevents the automatic remapping of touch into external space. We used fMRI to characterize how visual experience impacts on the brain circuits dedicated to the spatial processing of touch. Sighted and congenitally blind humans (male and female) performed a tactile temporal order judgment (TOJ) task, either with the hands uncrossed or crossed over the body midline. Behavioral data confirmed that crossing the hands has a detrimental effect on TOJ judgments in sighted but not in blind. Crucially, the crossed hand posture elicited more activity in a fronto-parietal network in the sighted group only. Psychophysiological interaction analysis revealed that the congenitally blind showed enhanced functional connectivity between parietal and frontal regions in the crossed versus uncrossed hand postures. Our results demonstrate that visual experience scaffolds the neural implementation of touch perception.Significance statementAlthough we seamlessly localize tactile events in our daily life, it is not a trivial operation because the hands move constantly within the peripersonal space. To process touch correctly, the brain has therefore to take the current position of the limbs into account and remap them to their location in the external world. In sighted, parietal and premotor areas support this process. However, while visual experience has been suggested to support the implementation of the automatic external remapping of touch, no studies so far have investigated how early visual deprivation alters the brain network supporting touch localization. Examining this question is therefore crucial to conclusively determine the intrinsic role vision plays in scaffolding the neural implementation of touch perception.


2016 ◽  
Vol 113 (40) ◽  
pp. 11172-11177 ◽  
Author(s):  
Shipra Kanjlia ◽  
Connor Lane ◽  
Lisa Feigenson ◽  
Marina Bedny

In humans, the ability to reason about mathematical quantities depends on a frontoparietal network that includes the intraparietal sulcus (IPS). How do nature and nurture give rise to the neurobiology of numerical cognition? We asked how visual experience shapes the neural basis of numerical thinking by studying numerical cognition in congenitally blind individuals. Blind (n = 17) and blindfolded sighted (n = 19) participants solved math equations that varied in difficulty (e.g., 27 − 12 = x vs. 7 − 2 = x), and performed a control sentence comprehension task while undergoing fMRI. Whole-cortex analyses revealed that in both blind and sighted participants, the IPS and dorsolateral prefrontal cortices were more active during the math task than the language task, and activity in the IPS increased parametrically with equation difficulty. Thus, the classic frontoparietal number network is preserved in the total absence of visual experience. However, surprisingly, blind but not sighted individuals additionally recruited a subset of early visual areas during symbolic math calculation. The functional profile of these “visual” regions was identical to that of the IPS in blind but not sighted individuals. Furthermore, in blindness, number-responsive visual cortices exhibited increased functional connectivity with prefrontal and IPS regions that process numbers. We conclude that the frontoparietal number network develops independently of visual experience. In blindness, this number network colonizes parts of deafferented visual cortex. These results suggest that human cortex is highly functionally flexible early in life, and point to frontoparietal input as a mechanism of cross-modal plasticity in blindness.


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