Role Reversal Imitation and Language in Typically Developing Infants and Children With Autism

Three types of role reversal imitation were investigated in typically developing 12‐ and 18‐month‐old infants and in children with autism and other developmental delays. Many typically developing infants at both ages engaged in each of the 2 types of dyadic, body‐oriented role reversal imitation: self‐self reversals, in which the adult acted on herself and the child then acted on himself, and other‐other reversals, in which the adult acted on the child and the child then acted back on the adult. However, 12‐month‐olds had more difficulty than 18‐month‐olds with triadic, object‐mediated role reversals involving interactions around objects. There was little evidence of any type of role reversal imitation in children with autism. Positive relations were found between role reversal imitation and various measures of language development for 18‐month‐olds and children with autism.     

Electrophysiological Brain Responses of Six‐Month‐Old Low Risk Premature Infants

This study sought to examine the electrophysiological correlates of visual perceptual priming in a sample of low risk preterm infants. We compared the ERP data of 20 healthy preterm infants at the age of 6 months (corrected age: 4 months) to those of 20 six‐month‐old and 20 four‐month‐old full term infants. The comparison groups represented the preterm infants' chronological and corrected ages respectively. The results showed that the brain responses of the preterm infants at the age of 6 months, specifically the topography and the latency of the Nc component, are more similar to those of their corrected age peers than to those of the chronological age controls.     

Auditory–Visual Context and Memory Retrieval in 3‐Month‐Old Infants

In 3 experiments, 3‐month‐old infants were trained to move an overhead mobile by kicking 1 of their feet in the presence of a distinctive visual (crib bumpers) and auditory (music) context. In Experiment 1A, 5‐day but not 1‐day retention was disrupted if either or both elements of the context present during the retention test were novel. In Experiment 1B, 5‐day retention was observed when only a single component of the training context, visual or auditory, was present. In Experiment 2, the retention test occurred at 14 days but it was preceded 24 hr earlier by a brief reactivation treatment. When the reactivation treatment consisted of reexposing the infant to the training crib bumpers and music, or just to the training music, it was not successful. Reactivation was successful when the reactivation treatment consisted of only the training crib bumpers. These results indicate that, in this paradigm, 3‐month‐old infants do not encode the elements of the context holistically and that, following forgetting, the visual contextual cues become dominant over the auditory contextual cues in facilitating retrieval.     

Looking Behavior at Test and Relational Memory in 6‐Month‐Old Infants

Small‐scale eye‐tracking research lends support to behavioral studies of relational memory by 6 months of life. Here, in the largest eye‐tracking test of relational memory to date (n = 276), we replicate these findings and examine the impact of excluding data based on looking behavior characteristics at test. Past work examining infants' preferential looking toward arbitrary‐paired objects and scenes has excluded infants from analysis based upon “insufficient looking” at test. Yet, research suggests that variation in looking behavior may be associated with looking patterns during encoding, as well as trait‐like differences in visual and cognitive processing. Similar to past research, we observed evidence for relational memory among 6‐month‐olds. In keeping with past research, when infants were excluded based on “insufficient looking,” we observed evidence for relational memory only when infants were tested immediately. However, when exclusion criteria were relaxed, infants specifically demonstrated preferential looking during a presumably more difficult delay‐plus‐interference condition. Moreover, analyses revealed that looking behavior during encoding was associated with looking behavior at test. Together, results suggest that infants do possess rudimentary relational memory capabilities, but that experimenters' ability to detect these capabilities is influenced by both experimental conditions and individual differences in looking behavior.     

Predisposing Factors for Elevated Restricted and Repetitive Behavior in Typically Developing Toddlers

Little is known about the relation between levels of restricted and repetitive behavior (RRB) in infants and parent factors. The present study investigated maternal and psychosocial factors (depressive symptoms, socio‐economic status, social support) and mother–infant engagement factors (mind‐mindedness, sensitivity, and infant–mother attachment security) as predictors of children's RRB at age 26 months in a sample of 206 mothers and children. Maternal depressive symptoms predicted levels of sensory and motor repetitive behavior and rigid, routinized, and ritualistic repetitive behavior. Lower socioeconomic status also predicted independent variance in children's sensory and motor repetitive behavior. The relations between maternal depressive symptoms and both types of RRB were not mediated through observational measures of maternal sensitivity or mind‐mindedness at 8 months, or attachment security at 15 months. The results are discussed in terms of whether stress regulation, self‐stimulation, and genetic susceptibility can help explain the observed link between maternal depressive symptoms and RRB in the child.     

The Onset of Working Memory in Infants

We used an optimized configuration of the delayed‐response task to explore the ability of young infants to remember which of 2 locations was correct across 12 trials after a 1‐ to 2‐sec delay. Performance improved with age, particularly after 5.5 months. These findings suggest an onset of appreciable working memory for many infants in the middle of their 6th month.     

Jealousy in 6‐Month‐Old Infants

Thirty‐two 6‐month‐old infants were exposed to their mothers attending, in turn, to a lifelike baby doll and a book. Infant negativity was greater when maternal attention was directed toward the social object, suggesting the presence of an early form of jealousy by 6 months of age.     

Hierarchical Processing in Seven‐Month‐Old Infants

Hierarchical structures are crucial to many aspects of cognitive processing and especially for language. However, there still is little experimental support for the ability of infants to learn such structures. Here, we show that, with structures simple enough to be processed by various animals, seven‐month‐old infants seem to learn hierarchical relations. Infants were presented with an artificial language composed of “sentences” made of three‐syllable “words.” The syllables within words conformed to repetition patterns based on syllable tokens involving either adjacent repetitions (e.g., dubaba) or nonadjacent repetitions (e.g., du ba du ) . Importantly, the sequence of word structures in each sentence conformed to repetition patterns based on word types (e.g., aba‐ abb ‐ abb ). Infants learned this repetition pattern of repetition patterns and thus likely a hierarchical pattern based on repetitions, but only when the repeated word structure was based on adjacent repetitions. While our results leave open the question of which exact sentence‐level pattern infants learned, they suggest that infants embedded the word‐level patterns into a higher‐level pattern and thus seemed to acquire a hierarchically embedded pattern.     

Syntactic Categorization in French‐Learning Infants

Recent work showed that infants recognize and store function words starting from the age of 6–8 months. Using a visual fixation procedure, the present study tested whether French‐learning 14‐month‐olds have the knowledge of syntactic categories of determiners and pronouns, respectively, and whether they can use these function words for categorizing novel words to nouns and verbs. The prosodic characteristics of novel words stimuli for noun versus verb uses were balanced. The only distinguishing cue was the preceding determiners versus subject pronouns, the former being the most common for nouns and the latter the most common for verbs, i.e., Det + Noun, Pron + Verb. We expected that noun categorization may be easier than verb categorization because the co‐occurrence of determiners with nouns is more consistent than that of subject pronouns with verbs in French. The results showed that infants grouped the individual determiners as one common class, and that they appeared to use the determiners to categorize novel words into nouns. However, we found no evidence of verb categorization. Unlike determiners, pronouns were not perceived as a common syntactic class.     

Phonological Specificity in 12‐ and 17‐Month‐Old French‐Speaking Infants

The literature reports some contradictory results on the degree of phonological specificity of infants’ early lexical representations in the Romance language, French, and Germanic languages. It is not clear whether these discrepancies are because of differences in method, in language characteristics, or in participants’ age. In this study, we examined whether 12‐ and 17‐month‐old French‐speaking infants are able to distinguish well‐pronounced from mispronounced words (one or two features of their initial consonant). To this end, 46 infants participated in a preferential looking experiment in which they were presented with pairs of pictures together with a spoken word well pronounced or mispronounced. The results show that both 12‐ and 17‐month‐old infants look longer at the pictures corresponding to well‐pronounced words than to mispronounced words, but show no difference between the two mispronunciation types. These results suggest that, as early as 12 months, French‐speaking infants, like those exposed to Germanic languages, already possess detailed phonological representations of familiar words.     

A Comparison of Men in Typically Male and Typically Female Operative Occupations

The authors use data from the General Social Surveys conducted from 1972 to 1985 to examine those personal and family characteristics which best discriminate men in typically male machine operative occupations from men in typically female machine operative occupations. Of the twelve personal and family characteristics considered, nine variables are found to discriminate between these two groups. The findings suggest that personal and family characteristics may shape occupational destinations for men in semi-skilled occupations.     

Global‐Before‐Basic Object Categorization in Connectionist Networks and 2‐Month‐Old Infants

A 3‐layered backpropagation connectionist network, configured as an autoassociator, learned to form global (e.g., mammal) before basic‐level (e.g., cat) category representations from perceptual input. To test the predicted global‐to‐basic order of category learning of the network, 2‐month‐olds were administered the familiarization/novelty‐preference procedure and examined for representation of global and basic‐level categories. Infants formed a global category representation for mammals that excluded furniture but not a basic‐level representation for cats that excluded elephants, rabbits, or dogs. The empirical results are consistent with the global‐to‐basic learning sequence observed in the network simulations.     

Temporal Sequence of Global‐Local Processing in 3‐Month‐Old Infants

In 3 experiments, the temporal processing sequence of local and global visual properties was investigated with 3‐month‐old infants. Across the experiments, a global pattern was discriminated under conditions of less familiarization than was necessary for local elements to be discriminated, thus indicating a global precedence in the sequence of visual processing at 3 months of age. Patterns of discrimination were also observed to vary as a function of individual differences in infants' look duration. Furthermore, the pattern of novelty and familiarity preferences for short‐looking infants varied in complex ways as a function of familiarization time: Preferences for novel global properties were supplanted by familiarity preferences at the point in familiarization at which infants first became sensitive to local properties.     

The Development of Rational Imitation in 9‐ and 12‐Month‐Old Infants

Studies on rational imitation have provided evidence for the fact that infants as young as 12 months of age engage in rational imitation. However, the developmental onset of this ability is unclear. In this study, we investigated whether 9‐ and 12‐month‐olds detect voluntary and implicit as well as nonvoluntary and explicit constraints in the head touch task. Three groups of infants watched video sequences, which displayed a person illuminating a lamp using the head. The hands of the model were either free, occupied by voluntarily holding a blanket, or nonvoluntarily restrained by being tied to the table. An additional control group of infants watched the model turning on the lamp by using the hand. Given that the majority of infants imitated the head touch when the model's hands were free, there was evidence for rational imitation in comparison to the condition in which the model's hands were tied to the table, but not in comparison to the condition in which the hands were occupied by holding a blanket. Nine‐month‐olds showed no differences in their behavior according to the condition. These findings clarify the onset of rational imitation by showing that 12‐month‐olds (but not 9‐month‐olds) take into account a situational constraint only when the constraint is nonvoluntary and explicit.     

Perception of Multisensory Gender Coherence in 6‐ and 9‐Month‐Old Infants

One of the most salient social categories conveyed by human faces and voices is gender. We investigated the developmental emergence of the ability to perceive the coherence of auditory and visual attributes of gender in 6‐ and 9‐month‐old infants. Infants viewed two side‐by‐side video clips of a man and a woman singing a nursery rhyme and heard a synchronous male or female sound track. Results showed that 6‐month‐old infants did not match the audible and visible attributes of gender, and 9‐month‐old infants matched only female faces and voices. These findings indicate that the ability to perceive the multisensory coherence of gender emerges relatively late in infancy and that it reflects the greater experience that most infants have with female faces and voices.     

Word Level Stress and Lexical Processing in 17‐Month‐Old Infants

Detailed representations enable infants to distinguish words from one another and more easily recognize new words. We examined whether 17‐month‐old infants encode word stress in their familiar word representations. In Experiment 1, infants were presented with pairs of familiar objects while hearing a target label either properly pronounced with the correct stress (e.g., baby /’be?bi/) or mis‐pronounced with the incorrect stress pattern (e.g., baby /be?’bi/). Infants mapped both the correctly stressed and mis‐stressed labels to the target objects; however, they were slower to fixate the target when hearing the mis‐stressed label. In Experiment 2, we examined whether infants appreciate that stress has a nonproductive role in English (i.e., altering the stress of a word does not typically signal a change in word meaning) by presenting infants with a familiar object paired with a novel object while hearing either correctly stressed or mis‐stressed familiar words (Experiment 2). Here, infants mapped the correctly stressed label to the familiar object but did not map the mis‐stressed label reliably to either the target or distractor objects. These findings suggest that word stress impacts the processing of familiar words, and infants have burgeoning knowledge that altering the stress pattern of a familiar word does not reliably signal a new referent.     

Recognition and Representation of Function Words in English‐Learning Infants

We examined infants' recognition of functors and the accuracy of the representations that infants construct of the perceived word forms. Auditory stimuli were “Functor + Content Word” versus “Nonsense Functor + Content Word” sequences. Eight‐, 11‐, and 13‐month‐old infants heard both real functors and matched nonsense functors (prosodically analogous to their real counterparts but containing a segmental change). Results reveal that 13‐month‐olds recognized functors with attention to segmental detail. Eight‐month‐olds did not distinguish real versus nonsense functors. The performance of 11‐month‐olds fell in between that of the older and younger groups, consistent with an emerging recognition of real functors. The three age groups exhibited a clear developmental trend. We propose that in the earliest stages of vocabulary acquisition, function elements receive no segmentally detailed representations, but such representations are gradually constructed so that once vocabulary growth starts in earnest, fully specified functor representations are in place to support it.     

Common Coding of Observation and Execution of Action in 9‐Month‐Old Infants

Do 9‐month‐old infants motorically simulate actions they perceive others perform? Two experiments tested whether action observation, like overt reaching, is sufficient to elicit the Piagetian A‐not‐B error. Infants recovered a toy hidden at location A or observed an experimenter recover the toy. After the toy was hidden at location B, infants in both conditions perseverated in reaching to A, demonstrating that active search by the infant is not necessary for the A‐not‐B error. Consistent with prior research, infants displayed an ipsilateral bias when reaching, the so‐called mysterious midline barrier. A similar ipsilateral bias was also observed depending on the manner in which the experimenter reached; infants perseverated following observation of ipsi‐ but not contralateral reaches by the experimenter. Thus, infants perseverated only following observation of actions they themselves were able to perform, suggesting that they coded others' actions in terms of motor simulation.     

Typical and Atypical Development of Visual Attention in 3‐ to 9‐Month‐Old Infants

The interactions between attention and stimulus encoding in infancy were examined using heart rate (HR) and visual habituation measures. At 3, 6, and 9 months of age, infants (N = 119) were habituated to an adult face; longest look (LL) duration was measured as an indicator of encoding speed. Three groups were formed based on LL change from 3 to 9 months: Large Decrease, Small Decrease, and Increase. Using concurrent electrocardiograph recordings, attention was measured through the percentage of looking time in orienting, sustained attention, and attention termination. We partially replicated previous findings regarding developmental patterns of attention in these three groups, notably that these patterns were different for the Increase group. Looks away from the stimulus were also assessed in each attentional phase and, as predicted, HR acceleration phases showed less visual engagement than HR deceleration phases. We also found anomalous behavior for the LL Increase group. In general, this small but distinct group showed similarities at 3 months to the presumably more mature behavior of typical 9 month olds, but by 9 months, they behaved more like typical 3 month olds regarding some, but not all, cognitive measures. These results are discussed in the context of the development of endogenous attention.