Generalization of learning from picture books to novel test conditions by 18- and 24-month-old children

Researchers know little about whether very young children can recognize objects originally introduced to them in a picture book when they encounter similar looking objects in various real-world contexts. The present studies used an imitation procedure to explore young children's ability to generalize a novel action sequence from a picture book to novel test conditions. The authors found that 18-month-olds imitated the action sequence from a book only when the conditions at testing matched those at encoding; altering the test stimuli or context disrupted imitation (Experiment 1A). In contrast, the 24-month-olds imitated the action sequence with changes to both the test context and stimuli (Experiment 1B). Moreover, although the 24-month-olds exhibited deferred imitation with no changes to the test conditions, they did not defer imitation with changes to the context and stimuli (Experiment 2). Two factors may account for the pattern of results: age-related changes in children's ability to utilize novel retrieval cues as well as their emerging ability to understand the representational nature of pictures.     

Foetal testosterone and vocabulary size in 18- and 24-month-old infants

Amniotic fluid, obtained from 87 pregnant women for routine amniocentesis, was analysed for foetal testosterone (FT) level. Their infants (40 girls and 47 boys) were followed up 18 and 24 months after birth and their vocabulary size was assessed. Girls were found to have a significantly larger vocabulary than boys at both ages. This replicates previous findings of a female advantage in language ability, but reveals this sex difference at the earliest point of development. Additionally, FT was an inverse predictor of vocabulary size when data from both sexes was examined together, but not within sex. The lack of a significant correlation between FT and vocabulary within each sex may reflect the relatively small sample size. However, the significant correlation between FT and vocabulary when the sexes were combined suggests FT might be involved in shaping the neural mechanisms underlying communicative development.     

The production of bimanual percussion in 12- to 24-month-old children

Bimanual coordination represents a complex self-organizing system that is subject to both internal and contextual constraints. Although there has been interest in examining bimanual development throughout the lifespan, few data exist relative to the bimanual activity of children between 1 and 4 years of age. The study reported here represents an initial effort to address this gap. Twenty-seven children who were either 12, 18 or 24 months old were videotaped while drumming with sticks on a plastic drum. Two independent observers recorded bout length as well as number and phase relation of movement cycles within bouts. Kinematic analysis provided more detailed information about the timing and form of children's activity. Results indicate that bimanual drumming becomes preferred over unimanual drumming by 2 years of age, that the proportions of different phase relations exhibited by children change between 1 and 2 years of age, and that the behavior appears to go through periods of stability and variability within this age range. These results are discussed in the context of the child's physical development and interactions with the environment during this period.     

Lexical stress and phonetic processing in word learning in 20- to 24-month-old English-learning children

To investigate the interaction between segmental and supra-segmental stress-related information in early word learning, two experiments were conducted with 20- to 24-month-old English-learning children. In an adaptation of the object categorization study designed by Nazzi and Gopnik (2001), children were presented with pairs of novel objects whose labels differed by their initial consonant (Experiment 1) or their medial consonant (Experiment 2). Words were produced with a stress initial (trochaic) or a stress final (iambic) pattern. In both experiments successful word learning was established when the to-be-remembered contrast was embedded in a stressed syllable, but not when embedded in unstressed syllables. This was independent of the overall word pattern, trochaic or iambic, or the location of the phonemic contrast, word-initial or -medial. Results are discussed in light of the use of phonetic information in early lexical acquisition, highlighting the role of lexical stress and ambisyllabicity in early word processing.     

Child and maternal correlates of impulse control in 24-month-old children

In two studies, we assessed the ability of 24-month-old children (N = 82) to delay a response to an attractive stimulus on a series of tasks administered by either the child's mother or a female adult stranger. In both studies, delay performance was consistent across tasks, but findings were inconsistent as to the effect on delay performance of a child's gender or the examiner's relationship to the child. Mothers' ratings of their children's personality predicted delay performance; superior performance was associated with low impulsivity, high attention span/persistence, and low sociability. Superior delay performance was also associated with low maternal directiveness as assessed on compliance tasks, and with mothers' encouragement of independence as assessed on a child-rearing attitude questionnaire.     

Concurrent relations between inhibitory control,vocabulary and internal state language in 18- and 24-month-old Italian-speaking infants

The aim of this study was to investigate the concurrent relations between 18- and 24-month-olds' performance on tasks measuring inhibitory control, word production, and internal state vocabulary. Two tasks were used to measure inhibitory control, the Reverse Categorization task (a conflict task), and the Gift task (a delay task). Expressive vocabulary was assessed with the Italian version of the MacArthur Communicative Development Inventory (Words and Sentences), and internal state vocabulary was assessed with a checklist of 78 mental state terms adapted from the English Internal State Language Questionnaire. Expressive vocabulary was associated to Internal State Language and to the Reverse Categorization task, but not to the Delay task. Our findings document internal state language abilities in a sample of 61 Italian-speaking children, and show that internal state vocabulary is significantly and specifically related only to performance on the conflict measure of inhibitory control, even when vocabulary size is controlled for. Results of our study extend to an Italian sample of children previous findings on an early association between self-control and theory of mind and suggest that a link between inhibitory control processes and internal state language may be present at a very young age.     

Categorization of two-dimensional and three-dimensional stimuli by 18-month-old infants

In two experiments, 18-month-old infants’ categorization of 3D replicas and 2D photographs of the same animals and vehicles were compared to explore infants’ flexibility in categorization across different object representations. Using a sequential touching procedure, infants completed one superordinate and two basic-level categorization tasks with 3D replicas, 2D cut out photographs, or 2D images on photo cubes (“2D cubes”). For superordinate sets, 3D replicas elicited longer mean run lengths than 2D cut outs, and 3D replicas elicited equivalent mean run lengths as 2D cubes. For basic-level sets, infants categorized high-contrast animal sets when presented with 3D replicas, but they failed to categorize any of the 2D photograph sets. Categorization processes appear to differ for 3D and 2D stimuli, and infants’ discovery of object properties over time while manipulating objects may facilitate categorization, as least at the superordinate level. These findings are discussed in the context of infants’ representation abilities and the integration of perception and action.     

12- and 18-month-old infants follow gaze to spaces behind barriers

Infants follow the gaze direction of others from the middle of the first year of life. In attempting to determine how infants understand the looking behavior of adults, a number of recent studies have blocked the adult's line of sight in some way (e.g. with a blindfold or with a barrier). In contrast, in the current studies an adult looked behind a barrier which blocked the child's line of sight. Using two different control conditions and several different barrier types, 12- and 18-month-old infants locomoted a short distance in order to gain the proper viewing angle to follow an experimenter's gaze to locations behind barriers. These results demonstrate that, contra Butterworth, even 12-month-old infants can follow gaze to locations outside of their current field of view. They also add to growing evidence that 12-month-olds have some understanding of the looking behaviors of others as an act of seeing.     

Televised social interaction and object learning in 14- and 18-month-old infants

We examined object learning in infants who viewed a televised adult speaking about a novel toy in videos that varied in the social cues provided. Novelty preference in following test trials differed as a function of televised social cues in 18-month-old, but not 14-month-old infants.     

Personalized interactive characters for toddlers' learning of seriation from a video presentation

Children's media is rooted in relationships with onscreen characters. In this study, 18-month-old toddlers were initially exposed to one of two unfamiliar interactive media characters for 3 months. Conditions varied whether the character was personalized to them or not. At age 21 months, toddlers were tested on a seriation task that was presented onscreen by the character and compared to the performance of a 21-month-old control group who did not view a video demonstration (total N = 48). Toddlers learned significantly more from the personalized character, but not from the non-personalized character, when compared to the control group. Children in the personalized condition also increased in parasocial, nurturing behaviors directed at the character during play sessions, and these scores were linked to better seriation performance. The results suggest an important role for social relationships with interactive characters to teach early seriation skills.     

Development of social perception: a conversation study of 6-, 12- and 36-month-old children

A conversation is made up of visual and auditory signals in a complex flow of events. What is the relative importance of these components for young children's ability to maintain attention on a conversation? In the present set of experiments the visual and auditory signals were disentangled in four filmed events. The visual events were either accompanied by the speech sounds of the conversation or by matched motor sounds and the auditory events by either the natural visual turn taking of the conversation or a matched turn taking of toy trucks. A cornea-reflection technique was used to record the gaze-pattern of subjects while they were looking at the films. Three age groups of typically developing children were studied; 6-month-olds, 1-year-olds and 3-year-olds. The results show that the children are more attracted by the social component of the conversation independent of the kind of sound used. Older children find spoken language more interesting than motor sound. Children look longer at the speaking agent when humans maintain the conversation. The study revealed that children are more attracted to the mouth than to the eyes area. The ability to make more predictive gaze shifts develops gradually over age.     

18- and 24-month-olds' discrimination of gender-consistent and inconsistent activities

18- and 24-month-olds' ability to discriminate gender-stereotyped activities was assessed. Using a preferential looking paradigm, toddlers viewed male and female actors performing masculine and feminine-stereotyped activities. Consistent with our predictions, and previous research, 24-month-olds, but not 18-month-olds, looked longer at the gender-inconsistent activities than the gender-consistent activities. Results are discussed in terms of toddlers emerging gender stereotypes and perception of everyday events.     

The relation between mirror self-image reactions and imitation in 14- and 18-month-old infants

Previous research suggests that sensitivity to aspects of the self and others develop in tandem. We tested 14- and 18-month-olds’ imitative abilities and mirror self-image reactions (i.e., testing behavior and passing the mark test). Results showed that 14-month-olds’ imitation was closely related to the occurrence of testing behavior in front of the mirror, where they checked whether they could control the movements of the mirror image. Eighteen-month-olds, however, no longer showed this relation. Furthermore, in 18-month-olds, we found a high association between imitation and passing the mark test. These correlations suggest that infants’ mirror self-image reactions and imitation share the ability to detect and produce visual-motor contingencies.     

Socialization and cognition in children between the age of 18 and 24 months

A cross-cultural study of mother–child dyads was set up to test the hypothesis that sociocultural differences, mediated by variations of maternal intervention, influence the way in which the child manipulates objects and, thereby, his cognitive and social competences. Two series of observations were conducted with three groups of children aged 18–24 months (15 from the American middle class, 15 from French families and 15 from North African families—the last two groups both underprivileged): (a) ‘naturalistic’ observations of two systems of interaction (child–mother and child–children interaction) showed that each child is characterized by one type of object manipulation (protected, induced, activated or autonomous) and that maternal intervention varies with the sociocultural background; assessment of the child's behavioural sequences unravelled his strategies for solving and avoiding conflicts with his peers; (b) observations of the child with a standardized material permitted an evaluation of his cognitive competences for spontaneous problem-solving. Regarding the assumptions of our hypothesis, the results furnish the following conclusions: (1) social and cognitive competences are related to the object manipulation type. In all samples, children characterized by ‘activated’ and ‘autonomous’ manipulation obtain the better results; (2) maternal intervention differs among the samples depending on the sociocultural background; these differences (limitation and physical contact) do not correspond to differences in types of manipulation; (3) type of manipulation is an interactive construction; it characterizes the functioning of the mother–child dyad and its prevailing dynamics between permanence and change. ©1997 by John Wiley & Sons, Ltd.     

An examination of spontaneous pointing in 20- to 50-month-old children.

Occurrences of spontaneous pointing in 20-, 30-, 40-, and 50-mo.-old children were observed during the children's indoor or outdoor free-play periods. Observers recorded the sex of the pointer, the behavioral pattern observed, the reason for the point, the response of the adult, and the distance of the child from the adult at the time of a point. Analysis indicated a significant dip in the rate of pointing among the 30-mo.-olds while the 20- and 50-mo.-olds were observed to point most often. With the exception of the 30-mo.-olds, pointing was significantly more likely to be observed in boys. For all age groups, the point was used primarily to name. After 20 months adults were significantly less likely to respond to the point, and when they did respond they were more likely to name or demonstrate irrespective of the apparent reason for the child's point. Finally, the probability of adults' response appeared to be unrelated to the distance from the child to the adult, and further, the likelihood of an adult's response appeared to exert little influence on the rate of pointing. The results suggest that pointing may be an expressive act that can be used as a communicative gesture, but there was little evidence that any of these age groups were using the point as a ritualized gesture, that is, as an action conventionalized within the context of social interaction.     

Waiting for a treat. Studying behaviors related to self-regulation in 18- and 24-month-olds

The ability to delay gratification – conceived as an early expression of self-regulation – develops in the second half of the second year of life. We used inductive methodology to identify different behaviors and set of behaviors performed by children while waiting for a treat. We asked which sets are more effective when it comes to successfully delaying gratification and how all observed sets change during toddler age. 130 children were tested twice – at 18 and at 24 months – using a Snack Delay Task. We observed 20 different behaviors and distinguished 4 sets of behaviors. The most important and effective set for delaying gratification in 18 and in 24 month olds was the set called Attention and Movements. We concluded that growth in the ability to delay gratification resulted from increased ability to overcome temptation by using an active strategy mainly based on attention.     

Communicative skills in relation to gender, birth order, childcare and socioeconomic status in 18-month-old children

Variation in communicative skills, defined as gestures, vocabulary comprehension and vocabulary production, was examined as a function of gender, birth order, childcare and socioeconomic status (SES) in 1,019 18-month-old children. The children were recruited at their regular check-up at a number of randomly selected Child Health Care centers in a Swedish county. The participation rate was 88%. The children were assessed by their mothers using a short version of the Swedish Early Communicative Development Inventories. The results demonstrate significant effects of gender and birth order on vocabulary comprehension and vocabulary production. Girls scored higher than boys and first-born children scored higher than later-born children. Type of childcare (family care, care at home and day-care centers) interacted with gender and birth order on vocabulary production and indicated that family care is not as advantageous as care at home or at day-care centers. SES had no effect on children's communicative skills at this age.     

Eighteen- and 24-month-old infants correct others in anticipation of action mistakes

Much of human communication and collaboration is predicated on making predictions about others' actions. Humans frequently use predictions about others' action mistakes to correct others and spare them mistakes. Such anticipatory correcting reveals a social motivation for unsolicited helping. Cognitively, it requires forward inferences about others' actions through mental attributions of goal and reality representations. The current study shows that infants spontaneously intervene when an adult is mistaken about the location of an object she is about to retrieve. Infants pointed out a correct location for an adult before she was about to commit a mistake. Infants did not intervene in control conditions when the adult had witnessed the misplacement, or when she did not intend to retrieve the misplaced object. Results suggest that preverbal infants anticipate a person's mistaken action through mental attributions of both her goal and reality representations, and correct her proactively by spontaneously providing unsolicited information.