Visual experience is not necessary for efficient survey spatial cognition: evidence from blindness

This study investigated whether the lack of visual experience affects the ability to create spatial inferential representations of the survey type. We compared the performance of persons with congenital blindness and that of blindfolded sighted persons on four survey representation-based tasks (Experiment 1). Results showed that persons with blindness performed better than blindfolded sighted controls. We repeated the same tests introducing a third group of persons with late blindness (Experiment 2). This last group performed better than blindfolded sighted participants, whereas differences between participants with late and congenital blindness were nonsignificant. The present findings are compatible with results of other studies, which found that when visual perception is lacking, skill in gathering environmental spatial information provided by nonvisual modalities may contribute to a proper spatial encoding. It is concluded that, although it cannot be asserted that total lack of visual experience incurs no cost, our findings are further evidence that visual experience is not a necessary condition for the development of spatial inferential complex representations.     

Visual experience is not necessary for efficient survey spatial cognition: Evidence from blindness

This study investigated whether the lack of visual experience affects the ability to create spatial inferential representations of the survey type. We compared the performance of persons with congenital blindness and that of blindfolded sighted persons on four survey representation-based tasks (Experiment 1). Results showed that persons with blindness performed better than blindfolded sighted controls. We repeated the same tests introducing a third group of persons with late blindness (Experiment 2). This last group performed better than blindfolded sighted participants, whereas differences between participants with late and congenital blindness were nonsignificant. The present findings are compatible with results of other studies, which found that when visual perception is lacking, skill in gathering environmental spatial information provided by nonvisual modalities may contribute to a proper spatial encoding. It is concluded that, although it cannot be asserted that total lack of visual experience incurs no cost, our findings are further evidence that visual experience is not a necessary condition for the development of spatial inferential complex representations.     

The recognition of emotional prosody in students with blindness: Effects of early visual experience and age development

This study examined the role of early visual experience and age in the recognition of emotional prosody among students with visual impairments in China. A total of 75 primary and junior high school students participated in the study. The ability of participants to recognize the prosody of four basic emotions (sadness, anger, happiness, and neutrality) was explored. The findings were as follows. (1) Early visual experience had a significant effect on the recognition of emotional prosody. The accuracy rate of students with congenital blindness was lower than that of students with adventitious blindness, and the performance of students with congenital blindness was lower than that of sighted students. The students with congenital blindness exhibited the slowest recognition speeds. (2) Age had a significant effect on the emotional prosody recognition accuracy of the sighted students, but it had no effect on the students with blindness.     

自内障手术治疗的发展与思考

白内障是常见的致盲眼病之一,目前治疗白内障唯一有效的方法是通过手术摘除混浊的晶状体并植入人工晶状体。随着白内障摘除手术技术的提高和仪器设备的不断更新,手术理念已由原来的白内障复明手术逐渐向白内障屈光手术转变,手术目的已不单纯局限在复明,而是旨在恢复更合乎生理状况的视觉功能。随着科学技术的发展,白内障手术技术的日趋成熟,人们关注的重点也逐渐从手术效果、术后视力的恢复,过渡到手术过程中患者的舒适程度、满意程度上来。使得白内障的手术治疗过程更具有人性化的特点,体现了当代医疗对患者的人文关怀。     

Vision following extended congenital blindness

Animal studies suggest that early visual deprivation can cause permanent functional blindness. However, few human data on this issue exist. Given enough time for recovery, can a person gain visual skills after several years of congenital blindness? In India, we recently had an unusual opportunity to work with an individual whose case history sheds light on this question. S.R.D. was born blind, and remained so until age 12. She then underwent surgery for the removal of dense congenital cataracts. We evaluated her performance on an extensive battery of visual tasks 20 years after surgery. We found that although S.R.D.'s acuity is compromised, she is proficient on mid- and high-level visual tasks. These results suggest that the human brain retains an impressive capacity for visual learning well into late childhood. They have implications for current conceptions of cortical plasticity and provide an argument for treating congenital blindness even in older children.     

Late‐ but not early‐onset blindness impairs the development of audio‐haptic multisensory integration

Integrating different senses to reduce sensory uncertainty and increase perceptual precision can have an important compensatory function for individuals with visual impairment and blindness. However, how visual impairment and blindness impact the development of optimal multisensory integration in the remaining senses is currently unknown. Here we first examined how audio‐haptic integration develops and changes across the life span in 92 sighted (blindfolded) individuals between 7 and 70 years of age. We used a child‐friendly task in which participants had to discriminate different object sizes by touching them and/or listening to them. We assessed whether audio‐haptic performance resulted in a reduction of perceptual uncertainty compared to auditory‐only and haptic‐only performance as predicted by maximum‐likelihood estimation model. We then compared how this ability develops in 28 children and adults with different levels of visual experience, focussing on low‐vision individuals and blind individuals that lost their sight at different ages during development. Our results show that in sighted individuals, adult‐like audio‐haptic integration develops around 13–15 years of age, and remains stable until late adulthood. While early‐blind individuals, even at the youngest ages, integrate audio‐haptic information in an optimal fashion, late‐blind individuals do not. Optimal integration in low‐vision individuals follows a similar developmental trajectory as that of sighted individuals. These findings demonstrate that visual experience is not necessary for optimal audio‐haptic integration to emerge, but that consistency of sensory information across development is key for the functional outcome of optimal multisensory integration.     

The role of visual experience in the production of emotional facial expressions by blind people: a review

Facial expressions of emotion are nonverbal behaviors that allow us to interact efficiently in social life and respond to events affecting our welfare. This article reviews 21 studies, published between 1932 and 2015, examining the production of facial expressions of emotion by blind people. It particularly discusses the impact of visual experience on the development of this behavior from birth to adulthood. After a discussion of three methodological considerations, the review of studies reveals that blind subjects demonstrate differing capacities for producing spontaneous expressions and voluntarily posed expressions. Seventeen studies provided evidence that blind and sighted spontaneously produce the same pattern of facial expressions, even if some variations can be found, reflecting facial and body movements specific to blindness or differences in intensity and control of emotions in some specific contexts. This suggests that lack of visual experience seems to not have a major impact when this behavior is generated spontaneously in real emotional contexts. In contrast, eight studies examining voluntary expressions indicate that blind individuals have difficulty posing emotional expressions. The opportunity for prior visual observation seems to affect performance in this case. Finally, we discuss three new directions for research to provide additional and strong evidence for the debate regarding the innate or the culture-constant learning character of the production of emotional facial expressions by blind individuals: the link between perception and production of facial expressions, the impact of display rules in the absence of vision, and the role of other channels in expression of emotions in the context of blindness.     

Ontogenetic shift of spectral phototactic preferences in anuran tadpoles.

Tadpoles of three species of anurans initially had a midspectrum ("green") preference in laboratory phototactic tests, which was shown experimentally to involve a form of true color vision in one species and probably in the other two as well. During development, the preference shifted to shorter wave-lengths (higher frequencies) until a short-wavelength ("blue") preference predominated in the pre- and postmetamorphic stages and in the adults of six species tested; color vision was involved in all of these stages. The green preference of young tadpoles is ecologically adaptive, in that it directs larvae to green plants that provide food or shelter. Tadpoles observed in a pond congregated heavily in vegetated areas rather than in open water. Spectroradiometric field measurements showed that pond illumination in vegetated areas had a more highly saturated yellow-green spectral dominance compared with a desaturated white illumination in open water. During all ontogenetic stages and as adults, the animals had a preference for high illuminance of white light, which correlates with the high illumination of their habitat. Microspectrophotometric data from Liebman and Entine suggested that the green rods are active receptors in tadpoles, making unlikely Muntz's hypothesis that the ontogenetic shift in spectral preferences is due to premetamorphic maturation of these receptors. However, the visual pigments of all five types of photoreceptors shifted from vitamin A2- to vitamin A1-based chromophores during ontogeny, and the resulting shift in spectral response of the receptors might be related to the spectral shift in phototactic preferences.     

Reduced adaptability,but no fundamental disruption,of norm‐based face coding following early visual deprivation from congenital cataracts

Faces are adaptively coded relative to visual norms that are updated by experience, and this adaptive coding is linked to face recognition ability. Here we investigated whether adaptive coding of faces is disrupted in individuals (adolescents and adults) who experience face recognition difficulties following visual deprivation from congenital cataracts in infancy. We measured adaptive coding using face identity aftereffects, where smaller aftereffects indicate less adaptive updating of face‐coding mechanisms by experience. We also examined whether the aftereffects increase with adaptor identity strength, consistent with norm‐based coding of identity, as in typical populations, or whether they show a different pattern indicating some more fundamental disruption of face‐coding mechanisms. Cataract‐reversal patients showed significantly smaller face identity aftereffects than did controls (Experiments 1 and 2). However, their aftereffects increased significantly with adaptor strength, consistent with norm‐based coding (Experiment 2). Thus we found reduced adaptability but no fundamental disruption of norm‐based face‐coding mechanisms in cataract‐reversal patients. Our results suggest that early visual experience is important for the normal development of adaptive face‐coding mechanisms.     

Adult visual experience promotes recovery of primary visual cortex from long-term monocular deprivation

Prolonged visual deprivation from early childhood to maturity is believed to cause permanent visual impairment. However, there have been case reports of substantial improvement of binocular vision in human adults following lifelong visual impairment or deprivation. These observations, together with recent findings of adult ocular dominance plasticity in rodents, led us to re-examine whether adult primary visual cortex (V1) is capable of any recovery following long-term monocular deprivation starting in development. Using mice as a model, we find that monocular deprivation from early development to mature ages (well past the critical period) severely impaired binocular vision by reducing the amplitude of responses elicited by stimulation of the deprived eye. Surprisingly, we find little effect on nondeprived eye responses. Restoration of binocular vision in mature adults yields modest but significant improvement of visual responses in V1. Remarkably, we find that when binocular vision is followed by occlusion of the nondeprived eye, visual responses in V1 recover almost fully, as measured by visual evoked potential amplitude, spatial frequency threshold, and single-unit activity. We conclude that adult V1 can recover from long-term deprivation when provided with an optimal regimen of visual experience.     

制约国人白内障复明手术的社会因素

全球因白内障致失明者大约2000万人,导致低视力者3倍于此数字,即6000万。手术可使白内障失明者视力恢复正常或有用视力。每年每百万人口接受白内障手术的人数（白内障手术率）是在不同环境中衡量眼保健工作的有用尺度。白内障手术率在各国之间以及一个国家的不同地区都存在极大差异,最高者比利时16000例／百万,2004年统计我...     

Conjoint measurement of gloss and surface texture

The image of a material's surface varies not only with viewing and illumination conditions, but also with the material's surface properties, including its 3-D texture and specularity. Previous studies on the visual perception of surface material have typically focused on single material properties, ignoring possible interactions. In this study, we used a conjoint-measurement design to determine how observers represent perceived 3-D texture ("bumpiness") and specularity ("glossiness") and modeled how each of these two surface-material properties affects perception of the other. Observers made judgments of bumpiness and glossiness of surfaces that varied in both surface texture and specularity. We quantified how changes in each surface-material property affected judgments of the other and found that a simple additive model captured visual perception of texture and specularity and their interaction. Conjoint measurement is potentially a powerful tool for analyzing perception of surface material in realistic environments.     

Vision Using Routines: A Functional Account of Vision

This paper presents the case for a functional account of vision. A variety of studies have consistently revealed “change blindness” or insensitivity to changes in the visual scene during an eye movement. These studies indicate that only a small part of the information in the scene is represented in the brain from moment to moment. It is still unclear, however, exactly what is included in visual representations. This paper reviews experiments using an extended visuo-motor task, showing that display changes affect performance differently depending on the observer's place in the task. These effects are revealed by increases in fixation duration following a change. Different task-dependent increases suggest that the visual system represents only the information that is necessary for the immediate visual task. This allows a principled exploration of the stimulus properties that are included in the internal visual representation. The task specificity also has a more general implication that vision should be conceptualized as an active process executing special purpose “routines” that compute only the currently necessary information. Evidence for this view and its implications for visual representations are discussed. Comparison of the change blindness phenomenon and fixation durations shows that conscious report does not reveal the extent of the representations computed by the routines.     

Early- and late-onset blindness both curb audiotactile integration on the parchment-skin illusion

It has been shown that congenital blindness can lead to anomalies in the integration of auditory and tactile information, at least under certain conditions. In the present study, we used the parchment-skin illusion, a robust illustration of sound-biased perception of touch based on changes in frequency, to investigate the specificities of audiotactile interactions in early- and late-onset blind individuals. Blind individuals in both groups did not experience any illusory change in tactile perception when the frequency of the auditory signal was modified, whereas sighted individuals consistently experienced the illusion. This demonstration that blind individuals had reduced susceptibility to an auditory-tactile illusion suggests either that vision is necessary for the establishment of audiotactile interactions or that auditory and tactile information can be processed more independently in blind individuals than in sighted individuals. In addition, the results obtained in late-onset blind participants suggest that visual input may play a role in the maintenance of audiotactile integration.     

Beyond the Grand Illusion: What Change Blindness Really Teaches Us About Vision

Experiments on scene perception and change blindness suggest that the visual system does not construct detailed internal models of a scene. These experiments therefore call into doubt the traditional view that vision is a process in which detailed representations of the environment must be constructed. The non-existence of such detailed representations, however, does not entail that we do not perceive the detailed environment. The “grand illusion hypothesis” that our visual world is an illusion rests on (1) a problematic “reconstructionist” conception of vision, and (2) a misconception about the character of perceptual experience.     

A possible explanation as to why the newly sighted commonly perform well on pseudoisochromatic colour vision tests

Patients whose vision has been restored after long periods of blindness commonly experience difficulty in perceiving. Parodoxically, such patients often perform well on pseudoisochromatic colour-vision tests. A well-known example is Gregory and Wallace's subject, S.B. who performance on the Ishihara test was perfect. It is suggested that restoration of vision may be associated with relatively poor visual acuity and that this, by filtering higher spatial frequencies, enhances the legibility of pseudoisochromatic test patterns. Two experiments confirm that the Ishihara plates are more legible when seen as defocused images.     

Imagery limitations in totally congenitally blind subjects

Research on totally blind subjects performing tasks that involve visual imagery has often shown that they do not behave differently from matched sighted subjects, even when their blindness is congenital. If visual imagery is based on visual perception, such tasks may not required visual imagery. In the present article visual images are considered as representations maintaining some properties of visible objects and constructed on the basis of information from various sources. Owing to the absence of visual experience, the limitations of such representations are explored in a series of experiments requiring memorization of single nouns, pairs of nouns, or triplets of nouns associated with a cue noun. Recall by blind subjects was impaired when multiple interactive images (with noun pairs and triplets) are formed. The poorer recall of blind subjects reflected also loss of order information. Recall was better for both groups with locative noun cues and high-imagery targets.     

Visuospatial skills and their association with math performance in girls with fragile X or Turner syndrome.

The present study was designed to assess object identification ("what") and location ("where") skills among girls with fragile X or Turner syndrome and girls with neither disorder. Participants completed standardized subtests of visual perception and tasks of visuospatial "what" and "where" memory. Girls with fragile X had average performance on most object identification tasks, yet 53% failed to accurately recreate the gestalt of a design during the "where" memory task. Fewer than 7% of girls in the Turner or comparison group made this error. Girls with Turner syndrome had lower scores and longer response times on object perception tasks and had poorer recall of location for internal features of the design on the "where" memory task, relative to girls in the comparison or fragile X group. When limiting analyses to IQ-matched samples, correlations between math and visual perception tasks emerged, but only for girls with fragile X. These results reflect important differences between two cognitive phenotypes and have implications for the role of visuospatial processing in early math performance.