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Abstract A striking demonstration that sound–object correspondences are not completely arbitrary is that adults map nonsense words with rounded vowels (e.g. bouba) to rounded shapes and nonsense words with unrounded vowels (e.g. kiki) to angular shapes (Köhler, 1947; Ramachandran & Hubbard, 2001). Here we tested the bouba/kiki phenomenon in 2.5‐year‐old children and a control group of adults (n =20 per age), using four pairs of rounded versus pointed shapes and four contrasting pairs of nonsense words differing in vowel sound. Overall, participants at both ages matched words with rounded vowels to the rounder shapes and words with unrounded vowels to the pointed shapes (both ps < .0005), with no significant difference between the two ages (p > .10). Such naturally biased correspondences between sound and shape may influence the development of language.

AbstractWe tested the effect of early monocular and binocular deprivation of normal visual input on the development of contour interpolation. Patients deprived from birth by dense central cataracts in one or both eyes, and age‐matched controls, discriminated between fat and thin shapes formed by either illusory or luminance‐defined contours. Thresholds indicated the minimum amount of curvature (the fatness or thinness) required for discrimination of the illusory shape, providing a measure of the precision of interpolation. The results show that individuals deprived of visual input in one eye, but not those deprived in both eyes, later show deficits in perceptual interpolation. The deficits were shown mostly for weakly supported contours in which interpolation of contours between the inducers was over a large distance relative to the size of the inducers. Deficits shown for the unilateral but not for the bilateral patients point to the detrimental effect of unequal competition between the eyes for cortical connections on the later development of the mechanisms underlying contour interpolation.

AbstractPatients deprived of visual experience during infancy by dense bilateral congenital cataracts later show marked deficits in the perception of global motion (dorsal visual stream) and global form (ventral visual stream). We expected that they would also show marked deficits in sensitivity to biological motion, which is normally processed in the superior temporal sulcus via input from both the dorsal and ventral streams. When tested on the same day for sensitivity to biological motion and to global motion at two speeds (4 and 18° s−1), patients, as expected, displayed a large deficit in processing global motion at both speeds. Surprisingly, they performed normally in discriminating biological motion from scrambled displays, tolerating as much noise as their age‐matched controls. Networks bypassing damaged portions of the dorsal and the ventral streams must mediate the spared sensitivity to biological motion after early visual deprivation.

Abstract Early experience preserves and refines many capabilities that emerge prenatally. Here we describe another role that it plays – establishing the neural substrate for capabilities that emerge at a much later point in development. The evidence comes from sleeper effects: permanent deficits when early experience was absent in capabilities that normally emerge long after birth. We provide evidence of sleeper effects for three aspects of vision, based on our research with children who were deprived of early visual input by congenital cataracts: contrast sensitivity for mid and high spatial frequencies, holistic face processing, and the ability to recognize the identity of faces based on small differences in the spacing among facial features.

We used two reaction time tasks to examine age differences in the ability to use an endogenous cue to shift attention covertly and to ignore distractors. In Experiment 1, 8‐year‐olds, 10‐year‐olds and adults (n = 24 per age) were asked to push a button as soon as they detected a target that was presented in a cued, miscued or non‐cued peripheral location at 100, 400 or 800 ms after the appearance of a central cue. In Experiment 2, 10‐year‐olds and adults (n = 24 per age) were asked to indicate which of two shapes appeared in the periphery 400 ms after a central cue, with those shapes surrounded by compatible or incompatible distractors. Unlike previous studies, the data were corrected for a reaction time bias that can inflate the apparent effect of cueing. Children were slower and more variable than adults overall. However, there were no age differences in the effects of the cues in either experiment: at all ages, the speed of responding was increased similarly by correct cueing and slowed similarly by incorrect cueing. Thus, under these conditions, the ability to use endogenous cues to orient covertly to the periphery is already adult‐like by 8–10 years of age, although there may be subsequent changes in the consistency of responding. In Experiment 2, 10‐year‐olds were slowed more than adults by incompatible distractors. Thus, the ability to ignore distracting information is not adult‐like even by 10 years of age. The findings suggest different rates of development for the ability to shift attention following an endogenous cue and for the ability to filter out irrelevant information.

Abstract In adults, facial identity is coded by opponent processes relative to an average face or norm, as evidenced by the face identity aftereffect: adapting to a face biases perception towards the opposite identity, so that a previously neutral face (e.g. the average) resembles the identity of the computationally opposite face. We investigated whether children as young as 8 use adaptive norm‐based coding to represent faces, a question of interest because 8‐year‐olds are less accurate than adults at recognizing faces and do not show the adult neural markers of face expertise. We found comparable face identity aftereffects in 8‐year‐olds and adults: perception of identity in both groups shifted in the direction predicted by norm‐based coding. This finding suggests that, by 8 years of age, the adaptive computational mechanisms used to code facial identity are like those of adults and hence that children's immaturities in face processing arise from another source.

Abstract In three experiments, we traced the development of the adult pattern of judgments of attractiveness for faces that have been altered to have internal features in low, average, or high positions. Twelve‐year‐olds and adults demonstrated identical patterns of results: they rated faces with features in an average location as significantly more attractive than faces with either low or high features. Although both 4‐year‐olds and 9‐year‐olds rated faces with high features as least attractive, unlike adults and 12‐year‐olds, they rated faces with low and average features as equally attractive. Three‐year‐olds with high levels of peer interaction, but not those with low levels of peer interaction, chose faces with low features as significantly more attractive than those with high‐placed features, possibly as a result of their increased experience with the proportions of the faces of peers. Overall, the pattern of results is consistent with the hypothesis that experience influences perceptions of attractiveness, with the proportions of the faces participants see in their everyday lives influencing their perceptions of attractiveness.

AbstractFaces 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.

AbstractWe used opposing figural aftereffects to investigate whether there are at least partially separable representations of upright and inverted faces in patients who missed early visual experience because of bilateral congenital cataracts (mean age at test 19.5 years). Visually normal adults and 10‐year‐olds were tested for comparison. Adults showed the expected opposing aftereffects for upright and inverted faces. Ten‐year‐olds showed an adultlike aftereffect for upright faces but, unlike the adult group, no aftereffect for inverted faces. Patients failed to show an aftereffect for either upright or inverted faces. Overall, the results suggest that early visual input is necessary for the later development of (at least partially) separable representations of upright and inverted faces, a developmental process that takes many years to reach an adult‐like refinement.

We evaluated the importance of early visual input for the later development of expertise in face processing by studying 17 patients, aged 10 to 38 years, treated for bilateral congenital cataracts that deprived them of patterned visual input for the first 7 weeks or more after birth. We administered five computerized tasks that required matching faces on the basis of identity (with changed facial expression or head orientation), facial expression, gaze direction and lip reading. Compared to an age–matched control group, patients' recognition of facial identity was impaired significantly when there was a change in head orientation (e.g. from frontal to tilted up), and tended to be impaired when there was a change in facial expression (e.g. from happy to surprised). Patients performed normally when matching facial expression and direction of gaze (e.g. looking left or right), and in reading lips (e.g. pronouncing 'u' or 'a'). The results indicate that visual input during early infancy is necessary for the normal development of some aspects of face processing, and are consistent with theories postulating the importance of early visual experience (de Schonen & Mathivet, 1989; Johnson & Morton, 1991) and separate neural mediation of different components of face processing (Bruce & Young, 1986).

AbstractBeing born at extremely low birth weight (ELBW; ≤1,000 g) is associated with enduring visual impairments. We tested for long‐term, higher order visual processing problems in the oldest known prospectively followed cohort of ELBW survivors. Configural processing (spacing among features of an object) was examined in 62 adults born at ELBW (Mage = 31.9 years) and 82 adults born at normal birth weight (NBW; ≥2,500 g: Mage = 32.5 years). Pairs of human faces, monkey faces, or houses were presented in a delayed match‐to‐sample task, where non‐matching stimuli differed only in the spacing of their features. Discrimination accuracy for each stimulus type was compared between birth weight groups, adjusting for neurosensory impairment, visual acuity, binocular fusion ability, IQ, and sex. Both groups were better able to discriminate human faces than monkey faces (p < .001). However, the ELBW group discriminated between human faces (p < .001), between monkey faces (p < .001), and to some degree, between houses (p < .06), more poorly than NBW control participants, suggesting a general deficit in perceptual processing. Human face discrimination was related to performance IQ (PIQ) across groups, but especially among ELBW survivors. Coding (a PIQ subtest) also predicted human face discrimination in ELBW survivors, consistent with previously reported links between visuo‐perceptive difficulties and regional slowing of cortical activity in individuals born preterm. Correlations with Coding suggested ELBW survivors may have used a feature‐matching approach to processing human faces. Future studies could examine brain‐based anatomical and functional evidence for altered face processing, as well as the social and memory consequences of face‐processing deficits in ELBW survivors.

AbstractThe expertise of adults in face perception is facilitated by their ability to rapidly detect that a stimulus is a face. In two experiments, we examined the role of early visual input in the development of face detection by testing patients who had been treated as infants for bilateral congenital cataract. Experiment 1 indicated that, at age 9 to 20, patients' accuracy and response times on a Mooney face detection task were normal. Experiment 2 revealed that the neural mechanisms underlying face detection in a similar group of adult patients are abnormal: the amplitude of both the P100 and N170 event‐related potential were larger in patients than in visually normal controls, and the extent of augmentation was related to the duration of deprivation. Thus, early visual experience is necessary for the establishment of normal neural networks for face detection; abnormalities at these early processing stages may contribute to the deficits we previously reported in configural face processing for this patient cohort.