Developmental Change in Infant Categorization: The Perception of Correlations among Facial Features

Previous studies indicated that the ability to detect correlations among attributes emerges between 7 and 10 months of age. In the present study, the generality of this developmental transition was examined. Using an infant-control habituation procedure, 48 7- and 10-month-old infants were tested for the perception of correlations among basic facial features. The developmental effects were replicated. Only the 10-month-old infants demonstrated their sensitivity to the pattern of correlation by generalizing to a novel face that preserved the experienced pattern of correlation, while showing increased attention to a face in which the pattern of correlation was violated. 7-month-old infants generalized to both test stimuli containing familiar features, regardless of the status of the correlation. Implications for face perception and the processing of categorical information are discussed.     

Infants' Forgetting of Correlated Attributes and Object Recognition

Infants as young as 3 months of age can encode the relations among object features. Because object recognition depends critically upon a match between perceived feature configurations and representations of the object in long-term memory, the present experiments focused on infants' long-term memory for feature correlations. In 3 experiments with 72 3-month-olds, we documented the forgetting functions of different feature correlations, examined their relation to infants' memory for individual features, and replicated the findings with different stimuli. Infants were trained to activate a mobile composed of two kinds of blocks that differed in color, the figures displayed on them, and the figures' colors and were tested after different delays with recombinations of either the block colors, the figures, or the figure colors. Infants remembered some of the original feature combinations for up to 3 days but forgot all of them after 4 days. Even after 4 days, however, infants remembered the individual features that had entered into the original combinations. These results demonstrate that very young infants not only encode the relations among object features but also remember them for several days. Moreover, there is a dissociation in memory between features and feature relations: Feature relations are forgotten sooner than the individual features that comprise those relations.     

Parsing Items into Separate Categories: Developmental Change in Infant Categorization

Three experiments report developmental change in infants' tendency to parse exemplars into separate categories. In Experiment 1, a familiarization-novelty preference procedure was used. Fifty-four 4-, 7-, and 10-month-old infants were familiarized with members of two basic-level animal categories (cats and horses) and tested with novel members of the familiarized categories and with members of a third category (dogs). In Experiment 2, a habituation-dishabituation procedure was used. Forty-eight 7- and 10-month-old infants were habituated to examples of both male and female faces and tested with novel gender-typical and gender-ambiguous faces. In both experiments, 10-month-old infants appeared to form differentiated categories, whereas younger infants formed a single category to include the range of items presented during familiarization. Experiment 3 ruled out a priori stimulus preferences as an explanation for the 10-month findings in Experiment 2.     

Visual-proprioceptive intermodal perception using point light displays

Three experiments explored 5- and 7-month-old infants' intermodal coordination of proprioceptive information produced by leg movements, and visual movement information specifying these same motions. The visual information took the form of point light information for leg and feet movements, with visual displays presented in upright, ego-centered on-joint (Experiment 1, N = 48); upright, ego-centered off-joint (Experiment 2, N = 48); and inverted, observer-centered off-joint (Experiment 3, N = 48) orientations. Measures of preferential looking indicated intermodal perception in infants of both ages while seeing on-joint, ego-centered orientations, and for 7-month-olds (and possibly 5-month-olds) while seeing off-joint, ego-centered displays; neither age group demonstrated intermodal perception for off-joint, observer-centered displays. These results suggest that coordination of visual and proprioceptive inputs is constrained by infants' information processing of the displays, and have implications for infants' growing understanding of their self-movement and the development of knowledge of the self.     

婴幼儿基于概念的归纳推理研究

近年来,关于婴幼儿归纳推理能力的发展研究受到国际心理学界的重视,其中婴幼儿是否能够基于概念进行归纳推理是一个焦点问题。Mandler等人利用概括化模仿技术对婴儿的归纳推理进行了研究,发现:9-20个月的婴儿的归纳推理受到领域水平的概念类别所限制,是一个基于概念的过程;Gelman等人探讨了类别成员关系、语言标签、心理本质主义在幼儿的归纳推理中的作用,发现:2-4岁幼儿的归纳推理受基本水平的类别成员关系所限制,也是一个基于概念的过程。二者的分歧可以用语言的作用加以解释。     

An Ordinal Pattern Analysis of Four Hypotheses Describing the Interactions between Drug-addicted, Chronically Disadvantaged, and Middle-Class Mother-Infant Dyads

This study investigated mother-infant interactions in 18 dyads. All participants were African American and enrolled in an early intervention program because the infants (2–26 months of age) had developmental disabilities or were at high risk for developmental disability. Some mothers had used drugs during their pregnancy, and all mothers were of low or middle socioeconomic status. Dyads were videotaped interacting at 4 different times, separated by at least 5 months in time. Videotapes were rated in terms of infant involvement and maternal responsivity in the interaction. 4 hypotheses concerning the pattern of maternal interaction across time were tested using ordinal pattern analysis. The hypothesis that mothers would become less responsive to infants over time (H_D) as a function of drug addiction, poverty, or serious developmental delay was supported for only 4 of the 18 dyads. There was support for the hypothesis (H_j) that mothers naturally increase their responsivity over time ( N = 6) and support for the hypothesis (H_T) that mothers' interactive sensitivity fluctuates in relation to infants' involvement in the interaction over time ( N = 7). Ordinal pattern analysis has advantages in determining how well competing hypotheses describe individuals within populations relative to approaches that identify differences that apply to entire populations.     

Infants' perception of the audible, visible, and bimodal attributes of multimodal syllables

Three experiments investigated 4-, 6-, and 8-month-old infants' perception of the audible, visible, and combined attributes of bimodally specified syllables. Ninety-six infants in each experiment were habituated to a person mouthing and uttering a syllable and then tested for detection of changes of either the audible, visible, or combined attributes of the syllable. When the attributes of the syllable were produced in an adult-directed manner, all three age groups discriminated the audible and bimodal attribute changes but only the 8-month-olds discriminated the visible one. When the difference between the familiar and novel attributes of the syllable was enhanced by testing with a novel syllable produced in an infant-directed manner, all three age groups detected all three types of changes. Finally, to test the possible role of audiovisual synchrony in responsiveness, infants were tested with an asynchronous syllable spoken either by the same person or by a novel person following habituation to a synchronous syllable. Results suggested that at four months infants attended primarily to the featural information, at six months primarily to the asynchrony, and at eight months to both features independently. These results help identify some of the important dimensions of multimodal speech during early development.     

What does it look like and what can it do? Category structure influences how infants categorize

Despite a large body of research demonstrating the kinds of categories to which infants respond, few studies have directly assessed how infants' categorization unfolds over time. Four experiments used a visual familiarization task to evaluate 10-month-old infants' (N = 98) learning of exemplars characterized by commonalities in appearance or function. When learning exemplars with a common function, infants initially responded to the common feature, apparently forming a category, and only learned the individual features with more extensive familiarization. When learning exemplars with a common appearance, infants initially learned the individual features and apparently only formed a category with more extensive familiarization. The results are discussed in terms of models of category learning.     

Infant visual attention in the paired-comparison paradigm: test-retest and attention-performance relations

The visual behavior of infants in the paired-comparison paradigm was assessed with multiple discrimination tasks week-to-week at 4 and 7 months and longitudinally from 4 to 7 months. Results indicated that although task-to-task reliability was extremely variable and typically low, most measures of infants' attention averaged across multiple tasks were reliable from 1 week to the next as well as relatively stable over the longer longitudinal period. Across all groups, infants who had shorter fixations (i.e., more fixations per fixed-exposure period) during the familiarization phase showed higher novelty preferences. While infants' shift rate during test phases was a reliable individual characteristic at 7 months, it was not at 4 months; rather, data suggested that the difficulty of the stimulus discrimination may be related to young infants' shift rate.     

Face processing in infancy: developmental changes in the use of different kinds of relational information

Adults use both first-order, or categorical, relations among features (e.g., the nose is above the mouth), and second-order, or fine spatial relations (e.g., the space between eyes), to process faces. Adults' expertise in face processing is thought to be based on the use of second-order relations. In the current study, 5-month-olds detected second-order changes, but 3-month-olds failed to detect second-order changes induced by 2 different manipulations. Three-month-olds did detect first-order changes, however. Also, inversion affected 5-month-olds' processing of second-order but not first-order information. These results suggest that, although sensitivity to first-order relations is available by 3 months or earlier, sensitivity to second-order information may not develop until sometime between 3 and 5 months of age.     

Domain general constraints on statistical learning

All theories of language development suggest that learning is constrained. However, theories differ on whether these constraints arise from language-specific processes or have domain-general origins such as the characteristics of human perception and information processing. The current experiments explored constraints on statistical learning of patterns, such as the phonotactic patterns of an infants' native language. Infants in these experiments were presented with a visual analog of a phonotactic learning task used by J. R. Saffran and E. D. Thiessen (2003). Saffran and Thiessen found that infants' phonotactic learning was constrained such that some patterns were learned more easily than other patterns. The current results indicate that infants' learning of visual patterns shows the same constraints as infants' learning of phonotactic patterns. This is consistent with theories suggesting that constraints arise from domain-general sources and, as such, should operate over many kinds of stimuli in addition to linguistic stimuli.     

Developmental changes in endogenous control of attention: the role of target familiarity on infants' distraction latency

This study evaluated the interactive effects of endogenous and exogenous influences on infants' attention allocation by assessing the role of target familiarity on distraction latency during object exploration. In Experiment 1 (N = 54), infants' distraction latencies as they investigated both familiar toys (ones they previously had seen in a familiarization procedure) and novel toys (ones they had not seen in the familiarization procedure) were assessed longitudinally at 6.5 and 9 months of age. In Experiment 2 (N = 32), infants' distraction latencies were assessed at either 6.5 or 10 months as they investigated either familiar or novel targets. In both experiments, older infants, but not younger infants, exhibited longer latencies as they investigated novel toys as compared with their latencies as they investigated familiar toys. These results are discussed in terms of developmental changes in the interactive effects of endogenous and exogenous factors controlling attention allocation.     

Longitudinal predictors of developmental status and social interaction in premature and full-term infants at age two

This investigation involved the longitudinal assessment of 30 mother-preterm and 40 mother-full-term dyads from birth to 2 years of age. Measures of maternal attitudes, maternal perception of the infant, and parental functioning were obtained at 1 and 8 months of infant age. Mother-infant interactions were observed at 4, 8, 12, and 24 months. Infant cognitive, motor, and language development was assessed at 4, 12, and 24 months. Results indicated that by age 2 years, no group differences were apparent on any child development, mother-child interaction, or maternal attitudinal measures; the lone exception was that preterms were significantly poorer in motor skills. This similarity in functioning at age 2 years was in marked contrast to earlier findings of major group differences at 12 months. Correlational and regression analyses indicated that the developmental and social interaction outcomes were predicted by different factors in the two groups; moreover, whereas 40%-60% of the variance in preterm infants' social and cognitive outcomes could be accounted for, only 15%-30% was accounted for in the full-term group. These results are discussed in terms of compensatory mechanisms that may characterize the parenting of high-risk infants, and of the applicability of transactional models of development.     

Organizational processes in infants' perception of auditory patterns

Infants 9-11 months of age were tested for their discrimination of changes in the melodic contour (direction of successive pitch changes) of brief melodies in the context of discernible variations in key (different absolute frequencies, same intervals) or interval size (different absolute frequencies and frequency ratios, same contour). Infants detected contour changes in both variable contexts, suggesting that they categorize sequences of sounds on the basis of global, relational properties such as melodic contour. Implications of such processing strategies for infants' perception of running speech are considered.     

The Development of a Linkage between Count Nouns and Object Categories: Evidence from Fifteen- to Twenty-One-Month-Old Infants

Recent research suggests that, although young children appreciate many different kinds of conceptual relations among objects, they focus specifically on taxonomic relations in the context of word learning. However, because the evidence for children's appreciation of this linkage between words and object categories has come primarily from children who have made substantial linguistic and conceptual advances, it offers limited information concerning the development of this linkage. In the experiments reported here, we employ a match-to-sample task to focus specifically on the development of an appreciation of the linkage between words (here, count nouns) and object categories in infants in the period just prior to and just subsequent to the naming explosion. The results demonstrate that, for 21-month-old infants, most of whom have recently entered the vocabulary explosion (Experiment 1), and for 16-month-old infants, most of whom have yet to commence the vocabulary explosion (Experiment 2), novel nouns focus attention on taxonomic relations among objects. This is important because it reveals a nascent appreciation of a linkage between words and object categories in infants who are at the very onset of language production. Results are interpreted within a developmental account of infants' emerging appreciation of a specific linkage between count nouns and object categories.     

Categorization skills in infants

The prototypical category-learning experiences with which infants are confronted are ones in which they have had prior experience with and have clearly noted the differences among a set of objects. Their task, then, is to notice also the similarities among the objects and to form a category based on these similarities. The goals of the current experiments were to create a laboratory situation in which it was clear that 10-month-old infants were distinguishing one category exemplar from another, and then to determine the structure of the category representation the infants developed under these learning conditions. A set of artificially created face stimuli was used in which the mean and modal prototypes were distinct. The infants' performance could not be explained by the context theory; they appear to have retained a count of the feature values observed during study. These data give support to the claim that prior to language, infants have available strategies for abstracting category-level information from their perceptual experiences with discriminable objects and events.     

Infants' perception of object trajectories

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.     

Vocabulary,Context, and Speech Perception Among Good and Poor Readers

This study examined the interaction between speech perception and sentential context among 13 poor readers and 49 good readers in grades one to three. Children's performance was examined on tasks assessing expressive and receptive vocabulary, reading skill, phonological awareness, pseudoword repetition, and phoneme identification. Good readers showed clearly defined categorical perception in the phoneme identification task for both sentence frames biased to the identification of the /b/ or /p/ phoneme. The /b/–/p/ category boundary for the BATH frame was at longer voice onset times (VOTs) than the boundary for PATH frame. Poor readers showed less sharply defined categorical perception with both sentence frames. Although poor readers did not show a shift in the /b/–/p/ category boundary, sentential context did affect the overall rate with which phonemes were identified as /b/ or /p/ at each VOT. These findings suggest that semantic information may operate as a compensatory mechanism for resolving ambiguities in speech perception. Furthermore, expressive vocabulary was more closely related than receptive vocabulary to individual differences in reading and phonological processing, providing support for the phonological distinctness hypothesis.     

Infants' perception of dynamic affective expressions: do infants distinguish specific expressions?

Seven-month-old infants' perception of positive (happy, interested) and negative (angry, sad) affective expressions was investigated using a preferential looking procedure (n = 20 in each of 6 conditions). The infants saw two videotaped facial expressions and heard a single vocal expression concordant with one of the facial expressions. The voice on the soundtrack was played 5 s out of synchrony with the ongoing affective visual display. Infants participated in one of six conditions (all possible pairs of the four expressive events). Infants' visual fixations to the affectively concordant and affectively discordant displays were recorded. Infants looked longer at the affectively concordant displays than at the affectively discordant displays in all conditions except the happy/sad and interested/sad conditions. For these two comparisons, facial discrimination was demonstrated by the infants' preferential looking at happy and interested expressions compared to the sad expression. Thus, 7-month-old infants discriminate among happy, interested, angry, and sad expressions, demonstrating differentiation among specific, dynamic expressions. The results are discussed in terms of the information specifying facial and vocal affect and the possible role of familiarity in learning to differentiate among affective expressions during infancy.     

An intersubjective developmental perspective on interactions between deaf and hearing mothers and their deaf infants

Most research into interactions between mothers and their infants with hearing impairments focuses on mothers' and infants' behaviors separately, speculating about the interplay among these behaviors and their effects on child development. In the present article, an intersubjective developmental theory focusing on the development of the "interworld" between deaf and hearing mothers and their deaf infants is used to integrate and interpret the seemingly incoherent research on early mother-deaf child interaction. Inspired by Stern's work (e.g., Stern, 1985), the intersubjective developmental theory distinguishes four stages in the development of intersubjectivity: emerging (birth-2 months), physical (2-8 months), existential (8-13 months), and symbolic (13 months and older), each characterized by a different type of mother-infant interaction. The integration of research findings on early mother-deaf child interaction into these four developmental stages offers new perspectives that can advance research and resolve certain early-intervention issues.