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We examined development of 5- and 10.5-month-old infants' face representations, focusing on infants' discrimination and categorization of female and male faces. We tested for gender-based preferences and categorization of female and male faces by presenting infants with pairs of faces and then habituating them to a series of majority female or male face ensembles. We then tested for gender preferences with new face pairs (one female and one male; Study 1) or new face ensembles (majority female and majority male; Study 2). We found that both 5- and 10.5-month-old infants discriminated female from male faces in face pairs, and both age groups looked more at female faces during habituation. Neither age group, however, provided evidence of gender-based categorization. We interpret these findings within a theoretical framework that stresses environmental exposure to different social categories, and infants' ability to detect commonalities of features within categories. We conclude that infants' gender-based categorization of faces is constrained by the set of features available in the input.

Mental rotation (MR) is the ability to transform a mental representation of an object so as to accurately predict how the object would look from a different angle (Sci 171:701-703, 1971), and it is involved in a number of important cognitive and behavioral activities. In this review we discuss recent studies that have examined MR in infants and the development of MR across the first year after birth. These studies have produced many conflicting results, yet several tentative conclusions can be reached. First, MR may be operational in infants as young as 3 months of age. Second, there may be sex differences in MR performance in infancy, in general favoring males, as there are in children and in adults. Third, there appear to be multiple influences on infants' MR performance, including infants' motor activity, stimulus or task complexity, hormones, and parental attitudes. We conclude by calling for additional research to examine more carefully the causes and consequences of MR abilities early in life.

Describes some general techniques for making collapsible models, including spiral models, for all the Platonic solids except the cube. Discusses the nature of the dissections of the faces necessary for the construction of the spiral cube. (ASK)

Describes how the film "The Dream Team" can be used in a small group communication course as a visual case study, presenting clearly and in detail many of the most central group development processes, including cohesiveness, norms, roles, leadership, and group development. (SR)

Rule learning (RL) refers to infants’ ability to extract high‐order, repetition‐based rules from a sequence of elements and to generalize them to new items. RL has been demonstrated in both the auditory and the visual modality, but no studies have investigated infants’ transfer of learning across these two modalities, a process that is fundamental for the development of many complex cognitive skills. Using a visual habituation procedure within a cross‐modal RL task, we tested 7‐month‐old infants’ transfer of learning both from speech to vision (auditory‐visual—AV—condition) and from vision to speech (visual‐auditory—VA—condition). Results showed a transfer of learning in the AV condition, but only for those infants who were able to efficiently extract the rule during the learning (habituation) phase. In contrast, in the VA condition infants provided no evidence of RL. Overall, this study indicates that 7‐month‐old infants can transfers high‐order rules across modalities with an advantage for transferring from speech to vision, and that this ability is constrained by infants’ individual differences in the way they process the to‐be‐learned rules.

Tracking adjacent (AD) and non-adjacent (NAD) dependencies in a sequence of elements is critical for the development of many complex abilities, such as language acquisition and social interaction. While learning of AD in infancy is a domain-general ability that is functioning across different domains, infants’ processing of NAD has been reported only for speech sequences. Here, we tested 9- to 12- and 13- to 15-month-olds’ ability to extract AxB grammars in visual sequences of unfamiliar elements. Infants were habituated to a series of 3-visual arrays following an AxB grammar in which the first element (A) predicted the third element (B), while intervening X elements changed continuously. Following habituation, infants were tested with 3-item arrays in which initial and final positions were switched (novel) or kept consistent with the habituation phase (familiar). Older infants successfully recognized the familiar AxB grammar at test, whereas the younger group showed some sensitivity to extract to NAD, albeit in a less robust form. This finding provides the first evidence that the ability to track NAD is a domain-general ability that is present also in the visual domain and that the sensitivity to such dependencies is related to developmental changes, as demonstrated in the auditory domain.

Psychological scientists have become increasingly concerned with issues related to methodology and replicability, and infancy researchers in particular face specific challenges related to replicability: For example, high-powered studies are difficult to conduct, testing conditions vary across labs, and different labs have access to different infant populations. Addressing these concerns, we report on a large-scale, multisite study aimed at (a) assessing the overall replicability of a single theoretically important phenomenon and (b) examining methodological, cultural, and developmental moderators. We focus on infants’ preference for infant-directed speech (IDS) over adult-directed speech (ADS). Stimuli of mothers speaking to their infants and to an adult in North American English were created using seminaturalistic laboratory-based audio recordings. Infants’ relative preference for IDS and ADS was assessed across 67 laboratories in North America, Europe, Australia, and Asia using the three common methods for measuring infants’ discrimination (head-turn preference, central fixation, and eye tracking). The overall meta-analytic effect size (Cohen’s d) was 0.35, 95% confidence interval = [0.29, 0.42], which was reliably above zero but smaller than the meta-analytic mean computed from previous literature (0.67). The IDS preference was significantly stronger in older children, in those children for whom the stimuli matched their native language and dialect, and in data from labs using the head-turn preference procedure. Together, these findings replicate the IDS preference but suggest that its magnitude is modulated by development, native-language experience, and testing procedure.

Compared to monolinguals, bilingual children attend more to pragmatic cues, especially when they conflict with perceptualcues (Brojde et al., 2012). This longitudinal eye-tracking study investigated monolingual and bilingual two-year-olds (T1M age=24.3 months; T2 M age=27.6 months) visual attention in a word learning paradigm containing a conflict betweeneye gaze (pragmatic cue) and object salience (perceptual cue). Participants saw videos of a model looked looking at andlabeling either a salient or a nonsalient object. Next, participants saw the objects from the videos side-by-side onscreen, andheard either the target label or a novel distracter label. At T1, monolinguals (N=14) and bilinguals (N=10) showed similarlooking patterns during learning; at test, bilinguals modulated their looking to target and distracter objects differently thanmonolinguals. At T2, monolinguals and bilinguals showed similar looking patterns during all trials. These results suggestthat language background may differentially influence word learning and visual attention across development.

Autism spectrum disorder (ASD) is a highly prevalent, lifelong condition characterized by impairments in social communication and the presence of restrictive, repetitive behaviors. Identifying the earliest signs of ASD is a critical factor in promoting optimal long-term outcomes for those affected. The developmental origins of ASD, including symptom onset and progression, remain poorly understood. Current known markers of ASD are centered on deviations in social and communicative skills that typically emerge around the first birthday; however, the presence of overt impairments reflects the consequence of an altered trajectory of social development, rather than the causes and underlying mechanisms from which these impairments arose. This has motivated the search for early risk markers more proximal to the source of deficits, including aberrations in early emerging neural systems that scaffold social development. Prior behavioral research has primarily focused the search within a single developmental domain, but this approach has fallen short of identifying reliable markers of ASD risk within the first 12 months. Instead, infants who develop ASD may exhibit impairments across several developmental domains, including diminished social attention in both visual and auditory domains as well as atypical brain organization in early infancy. This dissertation builds upon these bodies of research to provide a comprehensive profile of ASD risk in early infancy. The studies take a multimodal approach and employ eye-tracking, task-based and resting-state functional neuroimaging, and behavioral measures to investigate developmental antecedents of the social deficits and other core behavioral symptoms associated with ASD across early emerging domains critical for social development. Study 1 used eye-tracking methods to examine visual social attention to faces from 3- to 12-months of age in infants at high- and low-risk for ASD, as well as factors that may moderate developmental tr

We asked whether 11- and 14- month-old infants' abstract rule learning, an early form of analogical reasoning, is susceptible to processing constraints imposed by limits in attention and memory for sequence position. We examined 11- and 14- month-old infants' learning and generalization of abstract repetition rules ("repetition anywhere," Experiment 1 or "medial repetition," Experiment 2) and ordering of specific items (edge positions, Experiment 3) in 4-item sequences. Infants were habituated to sequences containing repetition- and/or position-based structure and then tested with "familiar" vs. "novel" (random) sequences composed of new items. Eleven-month-olds (N = 40) failed to learn abstract repetition rules, but 14-month-olds (N = 40) learned rules under both conditions. In Experiment 3, 11-month-olds (N = 20) learned item edge positions in sequences identical to those in Experiment 2. We conclude that infant sequence learning is constrained by item position in similar ways as in adults.

We examined mechanisms underlying infants' ability to categorize human biological motion stimuli from sex-typed walk motions, focusing on how visual attention to dynamic information in point-light displays (PLDs) contributes to infants' social category formation. We tested for categorization of PLDs produced by women and men by habituating infants to a series of female or male walk motions and then recording posthabituation preferences for new PLDs from the familiar or novel category (Experiment 1). We also tested for intrinsic preferences for female or male walk motions (Experiment 2). We found that infant boys were better able to categorize PLDs than were girls and that male PLDs were preferred overall. Neither of these effects was found to change with development across the observed age range (∼4-18 months). We conclude that infants' categorization of walk motions in PLDs is constrained by intrinsic preferences for higher motion speeds and higher spans of motion and, relatedly, by differences in walk motions produced by men and women.

We examined mechanisms underlying infants’ ability to detect, extract, and generalize sequential patterns, focusing on how saliency and consistency of distributional information guide infant learning of the most “likely” pattern in audiovisual sequences. In Experiment 1, we asked if 11- and 14-month-old infants could learn a “repetition anywhere” rule (e.g., ABBC, AABC, ABCC). In Experiment 2 we asked if 11- and 14-month-olds could generalize a “medial repetition” rule when its position is consistent in sequence, and in Experiment 3 we asked if 11-month-olds could identify a nonadjacent dependency occurring at edge positions. Infants were first habituated to 4-item sequences (shapes + syllables) containing repetition- and/or position-based structure, and were then tested with “familiar” structure instantiated across new items or combinations of items vs. “novel” (random) sequences. We found that 11-month-olds failed to learn the repetition rule both when the structure appeared in initial, medial, or final position (Experiment 1) and when it was restricted to the medial position (Experiment 2). Fourteen- month-olds learned repetition rules under both conditions. Finally, in Experiment 3 11-month-olds succeeded in learning a nonadjacent dependency in sequences identical to those used to test repetition learning in Experiment 2. Our results suggest that infants at 11 months, like adults, are relatively insensitive to patterns in the middle of sequences.

We recorded visual attention to same- and other-race faces in Hispanic and White 11-month-old infants, an age at which face processing is presumably biased by an own-race recognition advantage. Infants viewed pairs of faces differing in race or ethnicity as their eye movements were recorded. We discovered consistently greater attention to Black over Hispanic faces, to Black faces over White faces, and to Hispanic over White faces. Inversion of face stimuli, and infant ethnicity, had little effect on performance. Infants' social environments, however, differed sharply according to ethnicity: Hispanic infants are almost exclusively exposed to Hispanic family members, and White infants to White family members. Moreover, Hispanic infants inhabit communities that are more racially and ethnically diverse. These results imply that race-based visual attention in infancy is closely aligned with the larger society's racial and ethnic composition, as opposed to race-based recognition, which is more closely aligned with infants' immediate social environments.

Developing understanding of fractions involves connections between nonsymbolic visual representations and symbolic representations. Initially, teachers introduce fraction concepts with visual representations before moving to symbolic representations. Once the focus is shifted to symbolic representations, the connections between visual representations and symbolic notation are considered to be less useful, and students are rarely asked to connect symbolic notation back to visual representations. In 2 experiments, we ask whether visual representations affect understanding of symbolic notation for adults who understand symbolic notation. In a conceptual fraction comparison task (e.g., Which is larger, 5 / a or 8 / a?), participants were given comparisons paired with accurate, helpful visual representations, misleading visual representations, or no visual representations. The results show that even college students perform significantly better when accurate visuals are provided over misleading or no visuals. Further, eye-tracking data suggest that these visual representations may affect performance even when only briefly looked at. Implications for theories of fraction understanding and education are discussed.

Much research has documented learners’ ability to segment auditory and visual input into its component units. Two types of models have been designed to account for this phenomena: statistical models, in which learners represent statistical relations between elements, and chunking models, in which learners represent statistically coherent units of information. In a series of three experiments, we investigated how adults’ performance on a visual sequence-learning task aligned with the predictions of these two types of models. Experiments 1 and 2 examined learning of embedded items and Experiment 3 examined learning of illusory items. The pattern of results obtained was most consistent with the competitive chunking model of Servan-Schreiber and Anderson (1990). Implications for theories and models of statistical learning are discussed.

Statistical learning is characterized by detection of regularities in one's environment without an awareness or intention to learn, and it may play a critical role in language and social behavior. Accordingly, in this study we investigated the electrophysiological correlates of visual statistical learning in young children with autism spectrum disorder (ASD) using an event-related potential shape learning paradigm, and we examined the relation between visual statistical learning and cognitive function. Compared to typically developing (TD) controls, the ASD group as a whole showed reduced evidence of learning as defined by N1 (early visual discrimination) and P300 (attention to novelty) components. Upon further analysis, in the ASD group there was a positive correlation between N1 amplitude difference and non-verbal IQ, and a positive correlation between P300 amplitude difference and adaptive social function. Children with ASD and a high non-verbal IQ and high adaptive social function demonstrated a distinctive pattern of learning. This is the first study to identify electrophysiological markers of visual statistical learning in children with ASD. Through this work we have demonstrated heterogeneity in statistical learning in ASD that maps onto non-verbal cognition and adaptive social function.

Visual attention and perception develop rapidly during the first few months after birth, and these behaviors are critical components in the development of language and cognitive abilities. Here we ask how early bilingual experiences might lead to differences in visual attention and perception. Experiments 1-3 investigated the looking behavior of monolingual and bilingual infants when presented with social (Experiment 1), mixed (Experiment 2), or non-social (Experiment 3) stimuli. In each of these experiments, infants' dwell times (DT) and number of fixations to areas of interest (AOIs) were analyzed, giving a sense of where the infants looked. To examine how the infants looked at the stimuli in a more global sense, Experiment 4 combined and analyzed the saccade data collected in Experiments 1-3. There were no significant differences between monolingual and bilingual infants' DTs, AOI fixations, or saccade characteristics (specifically, frequency, and amplitude) in any of the experiments. These results suggest that monolingual and bilingual infants process their visual environments similarly, supporting the idea that the substantial cognitive differences between monolinguals and bilinguals in early childhood are more related to active vocabulary production than perception of the environment.

Previous work has demonstrated that infants use object trajectory continuity as a cue to the constant identity of an object, but results are equivocal regarding the role of object features, with some work suggesting that a change in the appearance of an object does not cue a change in identity. In an experiment involving 72 participants we investigated the effects of changing object shape and color, singly and in combination, on 4-month-olds' perception of object continuity. A change in the shape of an object while it passed behind an occluder had no effect on perception of continuity, whereas a change in shape and color led to perception of discontinuity, and a change in color led to no clear percept regarding continuity or discontinuity. These results are discussed in terms of a perceptual learning model of development of object identity.

Young infants perceive an object’s trajectory as continuous across occlusion provided the temporal or spatial gap in perception is small. In three experiments involving 72 participants we investigated the effects of different forms of auditory information on 4-month-olds’ perception of trajectory continuity. Provision of dynamic auditory information about the object’s trajectory enhanced perception of trajectory continuity. However, a smaller positive effect was also obtained when the sound was continuous but provided no information about the object’s location. Finally, providing discontinuous auditory information or auditory information that was dislocated relative to vision had negative effects on trajectory perception. These results are discussed relative to the intersensory redundancy hypothesis and emphasise the need to take an intersensory approach to infant perception.

We investigated oculomotor anticipations in 4-month-old infants as they viewed center-occluded object trajectories. In two experiments, we examined performance in 2D and 3D dynamic occlusion displays, and in an additional 3D condition with a smiley face as the moving target stimulus. Rates of anticipatory eye movements were not facilitated by 3D displays or by the (presumably) more salient smiley face relative to the 2D condition. However, latencies of anticipations were reduced, implying that 3D visual information may have supported formation of more robust mental representations of the moving object. Results are interpreted in a context of perceptual constraints on developing cognitive capacities in early infancy.

Although 4-month-olds perceive continuity of an object's trajectory through occlusion, little is known about the information specifying an occluding surface at this age. We investigated this in 3 experiments involving 84 participants. Testing the claim that 5-month-olds are unable to perceive the Kanizsa figure as an occluding surface (Csibra, 2001), we demonstrated that 4-month-olds perceived trajectory continuity behind this figure providing its horizontal extent was small. We demonstrated that the presence of visible occluding edges or occlusion of background was insufficient to specify an occluding surface but that their combination was sufficient. Thus, beyond object deletion and accretion, both visible occluding edges and occlusion of background are necessary for perception of occluding surfaces at this age.

One of the major areas of research into early cognitive development concerns infants' ability to understand number, given that it leads into later numerical and mathematical competence. Accordingly, there is considerable research on this topic and there is a large body of research suggesting that infants have a least some ability to discriminate between small number sets and large number sets. This chapter begins by describing the evidence for two types of representations of number-one for small item sets, the other for large-together with evidence that these systems are modality-general. This is followed by evidence suggesting that infants may sometimes be responding to continuous variables that are found in displays of discrete items rather than number per se. It then turns to the main focus of the chapter, which is whether infants can add and subtract, or whether their purported arithmetical abilities can be explained in lower-level perceptual terms. It is in this context that the relative contributions of information-processing perspectives are compared with other theoretical views on our understanding of infants' numerical abilities.

From birth, infants detect associations between the locations of static visual objects and sounds they emit, but there is limited evidence regarding their sensitivity to the dynamic equivalent when a sound-emitting object moves. In 4 experiments involving thirty-six 2-month-olds, forty-eight 5-month-olds, and forty-eight 8-month-olds, we investigated infants' ability to process this form of spatial colocation. Whereas there was no evidence of spontaneous sensitivity, all age groups detected a dynamic colocation during habituation and looked longer at test trials in which sound and sight were dislocated. Only 2-month-olds showed clear sensitivity to the dislocation relation, although 8-month-olds did so following additional habituation. These results are discussed relative to the intersensory redundancy hypothesis and work suggesting increasing specificity in processing with age.

After a brief familiarization period to either one or two toys 5-month olds gave a clear preference for perceptually novel displays suggesting that replicable findings of greater looking at an unexpected arithmetic outcome in addition/subtraction experiments cannot easily be attributed to simple familiarity preferences.

Stimulation of one sensory modality can induce perceptual experiences in another modality that reflect synaesthetic correspondences among different dimensions of sensory experience. In visual-hearing synaesthesia, for example, higher pitched sounds induce visual images that are brighter, smaller, higher in space, and sharper than those induced by lower pitched sounds. Claims that neonatal perception is synaesthetic imply that such correspondences are an unlearned aspect of perception. To date, the youngest children in whom such correspondences have been confirmed with any certainty were 2- to 3-year-olds. We examined preferential looking to assess 3- to 4-month-old preverbal infants' sensitivity to the correspondences linking auditory pitch to visuospatial height and visual sharpness. The infants looked longer at a changing visual display when this was accompanied by a sound whose changing pitch was congruent, rather than incongruent, with these correspondences. This is the strongest indication to date that synaesthetic cross-modality correspondences are an unlearned aspect of perception.

When viewing an event in which an object moves behind an occluder on part of its trajectory, 4-month-old infants perceive the trajectory as continuous only when time or distance out of sight is short. Little is known, however, about the conditions under which young infants perceive trajectories to be discontinuous. In the present studies we focus first on infants’ perception of trajectories that change during a period of occlusion. Four-month-olds perceive discontinuity in trajectories that change in height or orientation while behind an occluder, and this is true even when a change in direction could be due to an invisible bouncing collision with a surface. Further experiments reveal that infants do not perceive diagonal linear trajectories as continuous across an occlusion unless the occluding and revealing edges are orthogonal to the path of movement. Implications for theories of perceptual and cognitive development are discussed.

When an object moves behind an occluder and re-emerges, 4-month-old infants perceive trajectory continuity only when the occluder is narrow, raising the question of whether time or distance out of sight is the important constraining variable. One hundred and forty 4-month-olds were tested in five experiments aimed to disambiguate time and distance out of sight. Manipulating the object's visible speed had no effect on infants' responses, but reducing occlusion time by increasing object speed while occluded induced perception of trajectory continuity. In contrast, slowing the ball while it was behind a narrow or intermediate screen did not modify performance. It is concluded that 4-month-olds perceive trajectory continuity when time or distance out of sight is short.

Filling in the gaps in what humans see is a fundamental perceptual skill, but little is known about the developmental origins of occlusion perception. Three experiments were conducted with infants between 2 and 6 months of age to investigate perception of the continuity of an object trajectory that was briefly occluded. The pattern of results across experiments provided little evidence of veridical responses to trajectory occlusion in the youngest infants, but by 6 months, perceptual completion was more robust. Four–month–olds’ responses indicated that they perceived continuity under a short duration of occlusion, but when the object was out of sight for a longer interval, they appeared to perceive the trajectory as discontinuous. These results suggest that perceptual completion of a simple object trajectory (and, by logical necessity, veridical object perception) is not functional at birth but emerges across the first several months after onset of visual experience.

Several previous experiments have found that newborn and young infants will spend more time looking at attractive faces when these are shown paired with faces judged by adults to be unattractive. Two experimental conditions are described with the aim of finding whether the “attractiveness effect” results from attention to internal or external facial features, or both. Pairs of attractive and less attractive faces (as judged by adults) were shown to newborn infants (mean age 2 days, 9 hours), where each pair had either identical internal features (and different external features) or identical external features (and different internal features). In the latter, but not the former, condition the infants looked longer at the attractive faces. These findings are clear evidence that newborn infants use information about internal facial features in making preferences based on attractiveness. It is suggested that when newborn (and older) infants are presented with facial stimuli, whether dynamic or static, they are able to attend both to internal and external facial features.

Neonates seem to perceive two ends of a partly occluded rod as two separate objects. However, by 4 months of age infants often appear to perceive a similar stimulus as comprised of a single unified object. Little is known about the mechanisms of development underlying this change. We constructed four connectionist models of how perception of object unity might develop in human infants, based on experience with a variety of visual cues known to be important to infants' performance. After exposure to a simulated visual environment, ail the models were able to perceive a partly occluded object as unified. A rich perceptual environment and the presence of units for internal representations were found to improve generalization of acquired unity knowledge. These results lend plausibility to mechanistic accounts of human percepnial development, based on learning the statistical regularities inherent in the normal visual environment.