Joint attention and object learning in 5‐ and 7‐month‐old infants

We examined the effects of joint attention for object learning in 5‐ and 7‐month‐old infants. Infants interacted with an adult social partner who taught them about a novel toy in two conditions. In the Joint Attention condition, the adult spoke about the toy while alternating gaze between the infant and the toy, while in the Object Only condition, the adult looked to the toy and to a spot on the ceiling, but never at the infant. In the test trials following each social interaction, we presented infants with the ‘familiarization’ toy and a novel toy, and monitored looking times to each object. We found that 7‐month‐olds looked significantly longer to the novel toy following the Joint Attention relative to the Object Only condition, while 5‐month‐old infants did not show a significant difference across conditions. We interpret these results to suggest that joint attention facilitated 7‐month‐old infants' encoding of information about the familiarization object. Implications for the ontogeny of infant learning in joint attention contexts are discussed. Copyright © 2007 John Wiley & Sons, Ltd.     

Number discrimination in 10‐month‐old infants

Two experiments investigated developmental changes in large number discrimination with visual‐spatial arrays. Previous studies found that 6‐month‐old infants were able to discriminate arrays that differ by a ratio of 1:2 but not 2:3. We found that by 10 months, infants were able to reliably discriminate 8 from 12 elements (2:3) but not 8 from 10 elements (4:5). Thus, number discrimination improves in precision during the first year, and these findings converge with studies using auditory stimuli.     

Implicit meaning in 18‐month‐old toddlers

A substantial body of evidence demonstrates that infants understand the meaning of spoken words from as early as 6 months. Yet little is known about their ability to do so in the absence of any visual referent, which would offer diagnostic evidence for an adult‐like, symbolic interpretation of words and their use in language mediated thought. We used the head‐turn preference procedure to examine whether infants can generate implicit meanings from word forms alone as early as 18 months of age, and whether they are sensitive to meaningful relationships between words. In one condition, toddlers were presented with lists of words taken from the same taxonomic category (e.g. animals or body parts). In a second condition, words taken from two other categories (e.g. clothes and food items) were interleaved within the same list. Listening times were found to be longer in the related‐category condition than in the mixed‐category condition, suggesting that infants extract the meaning of spoken words and are sensitive to the semantic relatedness between these words. Our results show that infants have begun to construct the rudiments of a semantic system based on taxonomic relations even before they enter a period of accelerated vocabulary growth.     

Object individuation in 10‐month‐old infants: Manipulating the amount of introduction

The role of habituation/introduction as a possible confounder in the so‐called violation‐of‐expectation method has been discussed recently among infancy researchers. This study reports two experiments on object individuation in 10‐month‐old infants using the occlusion design employed by Xu and Carey (1996, Experiment 2). The first experiment replicated the procedure used by Xu and Carey (1996). In the second experiment the amount of introduction was reduced considerably. The first experiment replicated the original findings of Xu and Carey (1996): infants having unequivocal access to spatiotemporal information succeeded in object individuation, whereas those provided with feature/kind information did not. In the second experiment, however, infants failed in object individuation in both conditions. The findings are discussed in relation to the relevant literature.     

Shared musical knowledge in 11‐month‐old infants

Five‐month‐old infants selectively attend to novel people who sing melodies originally learned from a parent, but not melodies learned from a musical toy or from an unfamiliar singing adult, suggesting that music conveys social information to infant listeners. Here, we test this interpretation further in older infants with a more direct measure of social preferences. We randomly assigned 64 11‐month‐old infants to 1–2 weeks’ exposure to one of two novel play songs that a parent either sang or produced by activating a recording inside a toy. Infants then viewed videos of two new people, each singing one song. When the people, now silent, each presented the infant with an object, infants in both conditions preferentially chose the object endorsed by the singer of the familiar song. Nevertheless, infants’ visual attention to that object was predicted by the degree of song exposure only for infants who learned from the singing of a parent. Eleven‐month‐olds thus garner social information from songs, whether learned from singing people or from social play with musical toys, but parental singing has distinctive effects on infants’ responses to new singers. Both findings support the hypothesis that infants endow music with social meaning. These findings raise questions concerning the types of music and behavioral contexts that elicit infants’ social responses to those who share music with them, and they support suggestions concerning the psychological functions of music both in contemporary environments and in the environments in which humans evolved.     

Learning from others in 9‐18‐month‐old infants

The use of an adult as a resource for help and instruction in a problem solving situation was examined in 9, 14, and 18‐month‐old infants. Infants were placed in various situations ranging from a simple means‐end task where a toy was placed beyond infants' prehensile space on a mat, to instances where an attractive toy was placed inside closed transparent boxes that were more or less difficult for the child to open. The experimenter gave hints and modelled the solution each time the infant made a request (pointing, reaching, or showing a box to the experimenter), or if the infant was unable to solve the problem. Infants' success on the problems, sensitivity to the experimenter's modelling, and communicative gestures (requests, co‐occurrence of looking behaviour and requests) were analysed. Results show that older infants had better success in solving problems although they exhibited difficulties in solving the simple means‐end task compared to the younger infants. Moreover, 14‐ and 18‐month‐olds were sensitive to the experimenter's modelling and used her demonstration cues to solve problems. By contrast, 9‐month‐olds did not show such sensitivity. Finally, 9‐month‐old infants displayed significantly fewer communicative gestures toward the adult compared to the other age groups, although in general, all infants tended to increase their frequency of requests as a function of problem difficulty. These observations support the idea that during the first half of the second year infants develop a new collaborative stance toward others. The stance is interpreted as foundational to teaching and instruction, two mechanisms of social learning that are sometime considered as specifically human. Copyright © 2006 John Wiley & Sons, Ltd.     

Asymmetric interference in 3‐ to 4‐month‐olds' sequential category learning

Three‐ to 4‐month‐old infants show asymmetric exclusivity in the acquisition of cat and dog perceptual categories. The cat perceptual category excludes dog exemplars, but the dog perceptual category does not exclude cat exemplars. We describe a connectionist autoencoder model of perceptual categorization that shows the same asymmetries as infants. The model predicts the presence of asymmetric retroactive interference when infants acquire cat and dog categories sequentially. A subsequent experiment conducted with 3‐ to 4‐month‐olds verifies the predicted pattern of looking time behaviors. We argue that bottom‐up, associative learning systems with distributed representations are appropriate for modeling the operation of short‐term visual memory in early perceptual category learning.     

Humour Perception and Creation between Parents and 3‐ to 6‐month‐old Infants

Humour and laughter are universal to the human psychological experience and have serious developmental and evolutionary implications. Despite the early emergence of laughter in infancy, infants have been largely ignored in the humour research and humour has been largely ignored in the infant research. The present study describes the emergence of humour perception and creation in a sample of 20 parent–infant dyads who were followed from ages 3‐to‐ 6 months. The study examined how infants discover that absurd nonverbal behaviour, known as ‘clowning’, is amusing in the context of social engagement with caregivers. Results indicate that parents primarily use clowning when attempting to amuse their infants and pair these behavioural absurdities with affective cues like smiling and laughing. As they got older, infants were more likely to laugh and smile in response to clowning. Infants' ability to create humor via clowning also increased with age, starting with simple shrieks at 3 months to imitating absurd actions by 5 months. These increases are partly potentially explained by accompanying increases in parental smiling, laughing and clowning in response to infant clowning. Future research should employ more diverse samples and experimentally investigate the role of parental affect and social referencing in infants' interpretation of absurd behavior. Copyright © 2011 John Wiley & Sons, Ltd.     

Neural markers of subordinate‐level categorization in 6‐ to 7‐month‐old infants

Subordinate‐level category‐learning processes in infants were investigated with ERP and looking‐time measures. ERPs were recorded while 6‐ to 7‐month‐olds were presented with Saint Bernard images during familiarization, followed by novel Saint Bernards interspersed with Beagles during test. In addition, infant looking times were measured during a paired‐preference test (novel Saint Bernard vs. novel Beagle) conducted at the conclusion of ERP recording. Slow wave activity corresponded with learning a familiarized category at the subordinate and basic levels, whereas Negative central (Nc) and P400 components were linked with novel category preference. The results provide the first evidence identifying the neural markers of subordinate‐level categorization observed in looking‐time tasks conducted with infants. Moreover, when considered in conjunction with prior research investigating the neural markers of basic‐level categorization in infants, the findings indicate that (1) slow wave and Nc components of infant ERP waveforms are general markers for processes of category learning on the one hand and novel category preference on the other, (2) novel category preference for a contrast category at the basic and subordinate levels have the Nc component in common, but novel category preference at the subordinate level is accompanied by an additional P400 component, a finding in keeping with the notion that subordinate‐level categorization is governed by mechanisms supplementary to those underlying basic‐level categorization, and (3) slow wave activity associated with subordinate‐level learning followed that associated with basic‐level learning by approximately 200 ms, a result in accord with a coarse‐to‐fine scheme for the emergence of category partitioning.     

Sensitivity to social and non‐social threats in temperamentally shy children at‐risk for anxiety

In the current brief report, we examined threat perception in a group of young children who may be at‐risk for anxiety due to extreme temperamental shyness. Results demonstrate specific differences in the processing of social threats: 4‐ to 7‐year‐olds in the high‐shy group demonstrated a greater bias for social threats (angry faces) than did a comparison group of low‐shy children. This pattern did not hold for non‐social threats like snakes: Both groups showed an equal bias for the detection of snakes over frogs. The results suggest that children who are tempermentally shy have a heightened sensitivity to social signs of threat early in development. These findings have implications for understanding mechanisms of early threat sensitivity that may predict later socioemotional maladjustment.     

Electrophysiological responses to auditory novelty in temperamentally different 9‐month‐old infants

Behavioral reactivity to novel stimuli in the first half‐year of life has been identified as a key aspect of early temperament and a significant precursor of approach and withdrawal tendencies to novelty in later infancy and early childhood. The current study examines the neural signatures of reactivity to novel auditory stimuli in 9‐month‐old infants in relation to prior temperamental reactivity. On the basis of the assessment of behavioral reactivity scores at 4 months of age, infants were classified into groups of high negatively reactive and high positively reactive infants. Along with an unselected control group, these groups of temperamentally different infants were given a three‐stimulus auditory oddball task at 9 months of age which employed frequent standard and infrequent deviant tones as well as a set of complex novel sounds. In comparison to high positively reactive and control infants, high negatively reactive infants displayed increased amplitude of a positive slow wave in the ERP response to deviant tones compared to standard tones. In contrast, high positively reactive infants showed a larger novelty P3 to the complex novel sounds. Results are discussed in terms of optimal levels of novelty for temperamentally different infants.     

A case study of traumatic stress disorder in a 5‐month‐old infant following surgery

This case study of a 5‐month‐old infant describes the symptoms of trauma following a surgical procedure (cranial remodeling) with short‐term hospital stay. The infant showed a symptomatology similar to that found in other studies of hospitalization during the preverbal period, and fit the diagnosis of traumatic stress disorder according to the DC:0‐3. The therapy was implemented by the parents in consultation with the author. The approach was based on an exposure therapy model (flooding) using a somatic trauma trigger that occurred spontaneously in the context of a normal caretaking routine. The infant was allowed to have a full‐blown emotional response during several treatment sessions. The outcome was positive, with the disappearance of some symptoms of traumatic stress disorder after the first week, and no remaining symptoms after two months. Periodic follow‐up evaluations for one year revealed normal development with no return of symptoms. The symptoms, treatment, and outcomes are discussed in the context of behavioral learning theory and emotional processing theory. The role of crying during flooding therapy is discussed, and an emotional release theory emphasizing the therapeutic value of crying is proposed. Six cautionary guidelines are offered for the use of intense exposure therapy with infants.     

Habituation and novelty detection fNIRS brain responses in 5‐ and 8‐month‐old infants: The Gambia and UK

The first 1,000 days of life are a critical window of vulnerability to exposure to socioeconomic and health challenges (i.e. poverty/undernutrition). The Brain Imaging for Global Health (BRIGHT) project has been established to deliver longitudinal measures of brain development from 0 to 24 months in UK and Gambian infants and to assess the impact of early adversity. Here results from the Habituation‐Novelty Detection (HaND) functional near‐infrared spectroscopy (fNIRS) task at 5 and 8 months are presented (N = 62 UK; N = 115 Gambia). In the UK cohort distinct patterns of habituation and recovery of response to novelty are seen, becoming more robust from 5 to 8 months of age. In The Gambia, an attenuated habituation response is evident: a larger number of trials are required before the response sufficiently suppresses relative to the response during the first presented trials. Furthermore, recovery of response to novelty is not evident at 5 or 8 months of age. As this longitudinal study continues in The Gambia, the parallel collection of socioeconomic, caregiving, health and nutrition data will allow us to stratify how individual trajectories of habituation and recovery of response to novelty associate with different risk factors and adaptive mechanisms in greater depth. Given the increasing interest in the use of neuroimaging methods within global neurocognitive developmental studies, this study provides a novel cross‐culturally appropriate paradigm for the study of brain responses associated with attention and learning mechanisms across early development.     

Categorization and understanding of facial expressions in 4‐month‐old infants

This study examined whether 4‐month‐olds (N = 40) could perceptually categorize happy and angry faces, and show appropriate behavior in response to these faces. During the habituation phase, infants were shown the same type of facial expressions (happy or angry) posed by three models, and their behavior in response to those faces was observed. During the test phase immediately after the habituation phase, infants saw a novel emotional expression and a familiar expression posed by a new model, and their looking times were measured. The results indicated that, although 4‐month‐olds could perceptually categorize happy and angry faces accurately, they responded positively to both expression types. These findings suggest that, although infants can perceptually categorize facial expressions at 4 months of age, they require further time to learn the affective meanings of the facial expressions.     

Seven‐ to 9‐month‐old infants use facial expressions to interpret others' actions

In Study 1, 7‐month‐old infants (N = 58) looked reliably more at an adult's face when she playfully pulled a toy away from them compared with when she simply handed them the toy. In Study 2, 7‐ and 9‐month‐old infants (N = 36) interacted with an adult who played a teasing game and then held a neutral or happy facial expression. Compared with a baseline in which infants looked equally to both expressions, after the tease, infants looked longer at the neutral compared with the happy expression. By 7 months, infants may use facial expressions to disambiguate others' actions.     

The attentional ‘zoom‐lens’ in 8‐month‐old infants

The spatial attention mechanisms of orienting and zooming cooperate to properly select visual information from the environment and plan eye movements accordingly. Despite the fact that orienting ability has been extensively studied in infancy, the zooming mechanism – namely, the ability to distribute the attentional resources to a small or large portion of the visual field – has never been tested before. The aim of the present study was to evaluate the attentional zooming abilities of 8‐month‐old infants. An eye‐tracker device was employed to measure the saccadic latencies (SLs) at the onset of a visual target displayed at two eccentricities. The size of the more eccentric target was adjusted in order to counteract the effect of cortical magnification. Before the target display, attentional resources were automatically focused (zoom‐in) or spread out (zoom‐out) by using a small or large cue, respectively. Two different cue–target intervals were also employed to measure the time course of this attentional mechanism. The results showed that infants' SLs varied as a function of the cue size. Moreover, a clear time course emerged, demonstrating that infants can rapidly adjust the attentional focus size during a pre‐saccadic temporal window. These findings could serve as an early marker for neurodevelopmental disorders associated with attentional zooming dysfunction such as autism and dyslexia.     

Face detection in 2‐ to 6‐month‐old infants is influenced by gaze direction and species

Humans detect faces efficiently from a young age. Face detection is critical for infants to identify and learn from relevant social stimuli in their environments. Faces with eye contact are an especially salient stimulus, and attention to the eyes in infancy is linked to the emergence of later sociality. Despite the importance of both of these early social skills—attending to faces and attending to the eyes—surprisingly little is known about how they interact. We used eye tracking to explore whether eye contact influences infants' face detection. Longitudinally, we examined 2‐, 4‐, and 6‐month‐olds' (N = 65) visual scanning of complex image arrays with human and animal faces varying in eye contact and head orientation. Across all ages, infants displayed superior detection of faces with eye contact; however, this effect varied as a function of species and head orientation. Infants were more attentive to human than animal faces and were more sensitive to eye and head orientation for human faces compared to animal faces. Unexpectedly, human faces with both averted heads and eyes received the most attention. This pattern may reflect the early emergence of gaze following—the ability to look where another individual looks—which begins to develop around this age. Infants may be especially interested in averted gaze faces, providing early scaffolding for joint attention. This study represents the first investigation to document infants' attention patterns to faces systematically varying in their attentional states. Together, these findings suggest that infants develop early, specialized functional conspecific face detection.     

Parenting of 7‐month‐old infants at familial risk for attention deficit/hyperactivity disorder

Patterns of interaction between parents and 7‐month‐old boys at familial risk for attention deficit/hyperactivity disorder (ADHD) and a comparison group were studied during a warm‐up and two play episodes. The sample included 78 (47 at‐risk, 31 comparison) mother–child and 45 (27 at‐risk, 18 comparison) father–child dyads. A coding system developed by G. Kochanska (1997, 1998) was used. Infants in the risk group did not differ from the comparison group in the rate of emission of infant‐related events. However, they received less adequate responsivity from both their fathers and their mothers to these events, and specifically to negative emotions or distress, than did the comparison group. Maternal psychopathology did not account for these findings. Mothers were more adequately responsive than were fathers, especially for physiological needs. The association between nonoptimal interaction in infancy and the development of ADHD is discussed.     

Linking actions and emotions: Evidence from 15‐ and 18‐month‐old infants

This study investigated 15‐ and 18‐month‐olds' understanding of the link between actions and emotions. Infants watched a videotape in which three adult models performed an action on an object. Each adult expressed the same emotion (positive, negative, or neutral affect) on completion of the action. Infants were subsequently given 20 seconds to interact with the object. Infants were less likely to perform the target action after the models' expressed negative as opposed to positive or neutral affect. Although infants' imitative behaviour was influenced by the models' emotional displays, this social referencing effect was not apparent in their more general object‐directed behaviour. For instance, infants in the negative emotion condition were just as quick to touch the object and spent the same amount of time touching the object as did infants in the neutral and positive emotion conditions. These findings suggest that infants understood that the models' negative affect was in response to the action, rather than the object itself. Infants apparently used this negative emotional information to appraise the action as one that was ‘undesirable’ or ‘bad’. Consequently, infants were now loath to reproduce the action themselves.