Self-Corrected Reaching in a Three-Location Delayed-Response Search Task

Infants watched an experimenter hide a toy in one of three wells and then attempted to retrieve it after a brief delay. Seven-month-olds performed at chance. Nine-month-olds reached correctly on 43% of trials, which is significantly better than chance. After an incorrect reach, infants were allowed to choose between the two remaining locations. Seven-month-olds responded at a chance level on their second reach, but 9-month-olds chose correctly more often than would be expected by chance despite a 10- to 20-s delay between hiding and search. One cause of error on the initial reach was a profound bias toward the center well. In Experiment 2, the wells were covered simultaneously, and the infant's spatial orientation was disrupted during the delay; this procedure eliminated the centripetal bias. Nine-month-olds still responded correctly more often than would be expected by chance on their second reach. These findings suggest that 9-month-olds sometimes have a more durable working memory for location than is generally reported for that age group.     

Social looking,social referencing and humor perception in 6- and-12-month-old infants

Social referencing refers to infants’ use of caregivers as emotional referents in ambiguous situations (Walden, 1993). Studies of social referencing typically require ambulation, thereby over-looking younger, non-ambulatory infants (i.e., ≤8-months) and resulting in a widespread assumption that young infants do not employ this strategy. Using a novel approach that does not require mobility, we found that when parents provided unsolicited affective cues during an ambiguous-absurd (i.e., humorous) event, 6-month-olds employ one component of social referencing, social looking Additionally, 6-month-olds who did not laugh at the event were significantly more likely to look toward parents than their counterparts who found the event funny. Sequential analyses revealed that, following a reference to a smiling parent, 6-month olds were more likely to smile at the parent, but by 12 months were more likely to smile at the event suggesting that older infants are influenced by parental affect in humorous situations. The developmental implications of these findings are discussed, as well as the usefulness of studying humor for understanding important developmental phenomena.     

Facial experience during the first year

Parents of 2-, 5-, 8-, and 11-month-olds used two scales we developed to provide information about their infants' facial experience with familiar and unfamiliar individuals during one week. Results showed large discrepancies in the race, sex, and age of faces that infants experience during their first year with the majority of their facial experience being with their primary caregiver, females, and other individuals of the same-race and age as their primary caregiver. The infant's age and an unfamiliar individual's sex were predictive of their time spent interacting with one another. Moreover, an unfamiliar individual's sex was predictive of the attention infants allocated during social interactions. Differences in frequency and length of interactions with certain types of faces, as well as in infant attention toward certain individuals, all likely contribute to the development of expertise in processing commonly experienced face types and deficiencies in processing less commonly experienced face types.     

Generalization of deferred imitation during the first year of life

Infants first generalize across contexts and cues at 3 months of age in operant tasks but not until 12 months of age in imitation tasks. Three experiments using an imitation task examined whether infants younger than 12 months of age might generalize imitation if conditions were more like those in operant studies. Infants sat on a distinctive mat in a room in their home (the context) while an adult modeled actions on a hand puppet (the cue). When they were tested 24 h later, 6-month-olds generalized imitation when either the mat or the room (but not both) differed, whereas 9-month-olds generalized when both the mat and the room differed. In addition, 9-month-olds who imitated immediately also generalized to a novel test cue, whereas 6-month-olds did not. These results parallel results from operant studies and reveal that the similarity between the conditions of encoding and retrieval-not the type of task-determines whether infants generalize. The findings offer further evidence that memory development during infancy is a continuous function.     

Music therapy enhances preterm infant’s signs of engagement and sustains maternal singing in the NICU

Hospitalized preterm infants are exposed to stressful stimuli and early parental separation, which can undermine their long-term development and mother-infant bonding. Family-centered music therapy can enable positive mother-infant interactions, mediated by maternal infant-directed singing. This study aimed to investigate the effects of music therapy on preterm infant’s signs of engagement, namely Eye Opening (EO) and Smiling (SM), and maternal vocalizations. Participants were 30 mother-preterm infant dyads in a Brazilian Neonatal Intensive Care Unit (NICU), divided into a Music Therapy Group (MTG) and a Comparison Group (CG). The MTG participated in 6 sessions of the Music Therapy Intervention for the Mother-Preterm Infant Dyad (MUSIP), with the aim of supporting maternal singing with the infant. Prior to discharge, all mothers were filmed during a Non-singing (NS) and Singing (S) interactional condition; in the S condition, mothers were explicitly asked to address their infants by singing. Results of video and audio analysis showed that infants in the MTG displayed greater Eye Opening (EO) frequency compared to CG, but only when they were in an initial awake state at test, suggesting that music therapy can potentialize infants’ alertness, by increasing their disposition and chances of being engaged in the interaction with the mother. Non-religious mothers appeared to sing significantly more in the MTG than in the CG. These preliminary findings indicate that music therapy in the NICU could promote infant’s signs of engagement during interactions and can sustain maternal singing, especially with non-religious mothers in Brazil.     

Emerging perception of causality in action-and-reaction sequences from 4 to 6 months of age: Is it domain-specific?

Two experiments (N=136) studied how 4- to 6-month-olds perceive a simple schematic event, seen as goal-directed action and reaction from 3 years of age. In our causal reaction event, a red square moved toward a blue square, stopping prior to contact. Blue began to move away before red stopped, so that both briefly moved simultaneously at a distance. Primarily, our study sought to determine from what age infants see the causal structure of this reaction event. In addition, we looked at whether this causal percept depends on an animate style of motion and whether it correlates with tasks assessing goal perception and goal-directed action. Infants saw either causal reactions or noncausal delayed control events in which blue started some time after red stopped. These events involved squares that moved either rigidly or nonrigidly in an apparently animate manner. After habituation to one of the four events, infants were tested on reversal of the habituation event. Spatiotemporal features reversed for all events, but causal roles changed only in reversed reactions. The 6-month-olds dishabituated significantly more to reversal of causal reaction events than to noncausal delay events, whereas younger infants reacted similarly to reversal of both. Thus, perceptual causality for reaction events emerges by 6 months of age, a younger age than previously reported but, crucially, the same age at which perceptual causality for launch events has emerged in prior research. On our second question, animate/inanimate motion had no effect at any age, nor did significant correlations emerge with our additional tasks assessing goal perception or goal-directed object retrieval. Available evidence, here and elsewhere, is as compatible with a view that infants initially see A affecting B, without differentiation into physical or psychological causality, as with the standard assumption of distinct physical/psychological causal perception.     

Vocal responsiveness of preterm infants to maternal infant-directed speaking and singing during skin-to-skin contact (Kangaroo Care) in the NICU

Vocalizations of full-term newborns occur in a short latency time during the neonatal period. Contingent response time of preterm babies is still unknown. An increase of preterm babies’ vocalizations following exposure to parental speech was also observed. Mothers and babies co-modulate their vocalizations in preterm dyads. Purpose: To observe temporal features of maternal and infants’ vocalizations in speaking and singing conditions in preterm dyads. Methods: In a NICU mothers (N = 36) were invited to speak and to sing to their preterm infants during Kangaroo Care. Microanalysis of temporal units were performed with ELAN Software. Results and conclusions: Preterm infants vocalize less often while their mothers speak and sing than during baseline and their vocalizations tend to be more alternating in the speaking condition and more overlapping in the singing condition. It is also concluded that preterm infants take more time to respond to maternal speaking than to maternal singing.     

Object representation guides infants' reaching in the dark.

Infants were presented with two sounding objects of different sizes in light and dark, in which sound cued the object's identity. Reaching behavior was assessed to determine if object size influenced preparation for grasping the object. In both light and dark, infants aligned their hands when contacting the large object compared with the small object, which resulted in a reach with both hands extended for the large object and reach with one hand more extended for the small object. Infants contacted the large object more frequently on the bottom and sides rather than the top, where the sound source was located. Reaching in the dark by 6 1/2-month-olds is not merely directed toward a sound source but rather shows preparation in relation to the object's size. These findings were interpreted as evidence that mental representation of previously seen objects can guide subsequent motor action by 6 1/2-month-old infants.     

Infant behavioral responses to infant-directed singing and other maternal interactions

Seventy, 6-9-month-old infants were videotaped during six interactions: mother sings assigned song, "stranger" sings assigned song, mother sings song of choice, mother reads book, mother plays with toy, and mother and infant listen to recorded music. Infant-directed (ID) singing conditions elicited moderately positive cognitive behavior, low levels of positive physical behavior and minimal amounts of vocal behaviors, mostly negative. Across all conditions, cognitive scores remained positive at low to moderate levels. Physical responses were most positive during book and toy, most negative during recorded music, and differed by gender, especially during ID singing. Vocally, infants responded positively to toy, and 8-month-old infants vocalized more than younger infants, particularly during ID singing conditions. ID singing appears just as effective as book reading or toy play in sustaining infant attention and far more effective than listening to recorded music, while interactions involving objects may provide opportunity for shared attention.     

Infant effects on experimenter behavior

The present study explored experimenters’ looking behavior in a gaze-following task as a function of infant temperament. Two experienced female experimenters ran 62 15-month-olds through a six-trial gaze-following procedure in which infants were not distracted on the first three trials, but were distracted on the latter three trials by an Elmo video playing in the background. Although experimenters were trained to look at target objects for eight seconds per trial and were blind to infant temperamental status, both experimenters looked significantly longer during the non-distracted trials when infants were rated by their caregivers as high on effortful control or surgency. These results suggest that even experienced experimenters are susceptible to infant-driven influences. More importantly, these results highlight the importance of conceptualizing lab-based infant research involving human experimenters as, in Bronfenbrenner’s (1977) terms, representing the totality of a functional social system that does not exclude the experimenters.     

The song,not the singer: Infants prefer to listen to familiar songs,regardless of singer identity

Parent's infant-directed vocalizations are highly dynamic and emotive compared to their adult-directed counterparts, and correspondingly, more effectively capture infants’ attention. Infant-directed singing is a specific type of vocalization that is common throughout the world. Parents tend to sing a small handful of songs in a stereotyped way, and a number of recent studies have highlighted the significance of familiar songs in young children's social behaviors and evaluations. To date, no studies have examined whether infants’ responses to familiar versus unfamiliar songs are modulated by singer identity (i.e., whether the singer is their own parent). In the present study, we investigated 9- to 12-month-old infants’ (N = 29) behavioral and electrodermal responses to relatively familiar and unfamiliar songs sung by either their own mother or another infant's mother. Familiar songs recruited more attention and rhythmic movement, and lower electrodermal levels relative to unfamiliar songs. Moreover, these responses were robust regardless of whether the singer was their mother or a stranger, even when the stranger's rendition differed greatly from their mothers’ in mean fundamental frequency and tempo. Results indicate that infants’ interest in familiar songs is not limited to idiosyncratic characteristics of their parents’ song renditions, and points to the potential for song as an effective early signifier of group membership.     

Infants' Expectations in Play: The Joy of Peek-a-boo

Abstract

The role of expectations in infants' enjoyment of play was studied by observing their smiling, laughter, and eyebrow raises during a peek-a-boo game that contained occasional trick trials. In Experiments 1 and 2, 6, 7-, and 8-month-olds (n = 29) participated in a peek-a-boo game in which, on occasional “person-switch” trials, one adult hid and a second adult “reappeared” in his or her place. Infants in all age groups smiled less following person-switch reappearances than following normal ones, with the difference increasing with age. In Experiment 3, 7-month-old infants (n = 10) played a peek-a-boo game in which the adult occasionally reappeared in a different location. Smiling decreased for “location switches” just as it had for person switches. Infants in all age groups were more likely to exhibit eyebrow raises following trick reappearances than following normal ones. These findings suggest that infants as young as 6 months have expectations about the identity and location of a returning person, that conformity to these expectations contributes to infants' enjoyment of games such as peek-a-boo, and that infants of this age may not yet enjoy deviations from their expectations. Implications are discussed for theories of playful enjoyment, for the cognitive antecedents of positive affect, and for cognitive development.     

The link between maternal interaction style and infant action understanding

The present study investigates whether the maternal interaction style is related to 6-month-old infants' action interpretation. We tested 6-month-olds ability to interpret an unfamiliar human action as goal-directed using a modified version of the paradigm used by Woodward, A. L. (1999). Infant's ability to distinguish between purposeful and non-purposeful behaviours. Infant Behavior & Development, 22, 145-160 and Király, I., Jovanovic, B., Prinz, W., Aschersleben, G., & Gergely, G. (2003). The early origins of goal attribution in infancy. Consciousness & Cognition, 12, 732-751. Additionally, all infants and their mothers participated in a free play situation to assess maternal interaction styles as measured by the CARE-Index. According to mothers' distinct interaction styles, infants were divided into three groups. Results suggest that at 6 months of age infants of mothers with a modestly controlling interaction style are better at interpreting a human action as goal-directed than infants of sensitive and relative unresponsive mothers. The ability to understand human action as goal-directed might be a corollary of an adaptive strategy in infancy.     

Infants’ understanding of everyday social interactions: A dual process account

Six- and 12-month-old infant’s eye movements were recorded as they observed feeding actions being performed in a rational or non-rational manner. Twelve-month-olds fixated the goal of these actions before the food arrived (anticipation); the latency of these gaze shifts being dependent (r = .69) on infants life experience being feed. In addition, 6- and 12-month-olds dilated their pupil during observation of non-rational feeding actions. This effect could not be attributed to light differences or differences in familiarity, but was interpreted to reflect sympathetic-like activity and arousal caused by a violation of infant’s expectations about rationality. We argue that evaluation of rationality requires less experience than anticipations of action goals, suggesting a dual process account of preverbal infants’ everyday action understanding.     

An investigation of young infants' perceptual representations of speech sounds

The present study examined the ability of newborns and 2-month-olds to detect phonetic differences between syllables. By relying on the modified high-amplitude sucking procedure, which did not permit the infants to use a simple same-different response, the present experiments tapped the perceptual representations of the speech sounds. Infants as young as a few days old displayed some capacity to represent differences in a set of syllables varying in their phonetic composition, although there was no convincing evidence that their representations were structured in terms of phonetic segments. Finally, evidence of developmental changes in speech processing were noted for the first time with infants in this age range. The change noted was a tendency from global toward more specific representations on the part of the older infants.     

Acoustic parameters of infant-directed singing in mothers with depressive symptoms

The purpose of this study was to explore the relationship between mothers’ depressive symptoms and the acoustic parameters of infant-directed (ID) singing. Participants included 80 mothers and their 3- to 9-month-old infants. A digital recording was made of each mother's voice while singing to her infant. Extraction and analyses of vocal data revealed a main effect of tempo, meaning that as mothers reported more depressive symptoms, they tended to sing faster to their infants. Additionally, an interaction effect indicated that mothers with depressive symptoms were more likely to sing with tonal key clarity to their male infants. These findings suggest that as mothers experience depressive symptoms, their ID singing may lack the sensitivity and emotional expression that infants need for affect regulation. An intervention that combines interaction coaching and ID singing may help mothers with depressive symptoms to engage in sensitive and emotionally synchronized interactions with their infants.     

Nine- and twelve-month-old infants relate emotions to people's actions

Under investigation was whether 9- to 12-month-olds appreciate that a person's expression of pleasure when gazing toward an object is consistent with that person's subsequent handling of the object. Infants were randomly assigned to an experimental and control group. In the experimental group infants during the pretrials saw a Happy or an Unhappy person saying either “Oh I like objects” or, “I don't like objects”, respectively, while looking at an abstract object. In the habituation phase, infants saw an actor holding the abstract object, but the emotional expression of the actor was obscured. In the posttrial, infants were alternately presented with either the Happy or the Unhappy actor holding the object. In the control group, infants received the same three phase procedure, except that no object was present during the pre- and habituation trials. Analyses comparing the between-subjects variables revealed that infants in the Experimental group looked significantly longer at the Unhappy actor than infants in the Control group but less long at the Happy actor. This study is the first to compare positive and negative emotions and to show that infants as young as 9 months use these emotions to make inferences about people's subsequent actions on objects.     

Preference for peers in infancy

Previous findings suggest that infants prefer other infants from among individuals of various ages. There are two explanations for this: one is that like adults, infants prefer babyish characteristics; the other is that infants prefer individuals who are similar to themselves. We examined whether infants respond differently to same-age infants from among older or younger infants. This might allow the possibility of methodologically separating the two explanations for peer preference in infancy. The results revealed that 9-month-olds showed peer preference when they saw movies of infants. Further experiments showed that 6- and 9-month-olds preferred static images of same-age infants. The lack of preference of 6-month-olds for movies of same-age infants could be related to their ability to process information. Thus, the cue for peer preference may be physical similarity to oneself, rather than the strength of babyish characteristics reflecting a particular developmental stage.     

Development of attention and distractibility in the first 4 years of life

This observational study describes the early development of attention and discractibility. Under several conditions of distraction, 172 children at 10, 26, and 42 months of age played with toys. Attention to the toys was coded as casual, settled, or focused. All 3 levels of attention changed with age, withcasual attention decreasing and focused attention increasing. The 10-month-olds were more distractible than the other children, even during focused attention. The infants were most distracted by the auditory-visual distractor, whereas the oldest children were most distracted by the visual distractor. Some 42-month-olds showed evidence of being more focused in the presence of distractors. Overall, the results point to a developmental transition in the processes underlying attention during play.     

Ontogeny of early event memory: II. Encoding and retrieval by 2- and 3-month-olds

The ability of 2-month-old infants to discriminate changes in a 5-object crib mobile following a retention interval of 24 hr was assessed using the mobile conjugate reinforcement paradigm. Infants were trained in 3 daily 15-min sessions to produce mobile movement by footkicking. Twenty-four hr later, independent groups received generalization tests with mobiles containing 1–5 novel objects substituted into their original training mobile. A control group was tested with the original training mobile. These findings were compared with findings of 2 previous studies involving identical procedures with 3-month-olds, reanalyzed for measures of individual performance over successive test minutes. Although, in absolute terms, 2-month-olds had a flat generalization gradient relative to 3-month-olds, when each infant's kick rate during the generalization test was expressed relative to that infant's kick rate before, and at the end of, training, it was found that the generalization gradients of 2- and 3-month-olds were indistinguishable. The relative response measures indicated a surprising degree of specificity by both age groups: Test mobiles containing more than 1 novel object did not cue retrieval, but test mobiles containing no more than 1 new object yielded perfect retention and complete generalization. These data indicate that infants as young as 2 months are capable of encoding and maintaining a representation of the specific details of their training context for at least 24 hr and, after that delay, can perform fine discriminations based on the discrepancy between their test context and that representation.