Infants' responses to facial and vocal emotional signals in a social referencing paradigm

The independent effects of facial and vocal emotional signals and of positive and negative signals on infant behavior were investigated in a novel toy social referencing paradigm. 90 12-month-old infants and their mothers were assigned to an expression condition (neutral, happy, or fear) nested within a modality condition (face-only or voice-only). Each infant participated in 3 trials: a baseline trial, an expression trial, and a final positive trial. We found that fearful vocal emotional signals, when presented without facial signals, were sufficient to elicit appropriate behavior regulation. Infants in the fear-voice condition looked at their mothers longer, showed less toy proximity, and tended to show more negative affect than infants in the neutral-voice condition. Happy vocal signals did not elicit differential responding. The infants' sex was a factor in the few effects that were found for infants' responses to facial emotional signals.     

Visual experience influences 12-month-old infants' perception of goal-directed actions of others.

In the present study, we investigated whether infants' own visual experiences affected their perception of the visual status of others engaging in goal-directed actions. In Experiment 1, infants viewed video clips of successful and failed goal-directed actions performed by a blindfolded adult, with half the infants having previously experienced being blindfolded. The results showed that 12-month-old infants who were previously blindfolded preferred to look longer at the demonstrator's successful actions, whereas no such preference was observed in 8-month-old infants. In Experiment 2, infants watched the same 2 actions when the adult demonstrator was not blindfolded. The responses of 12-month-old infants were the opposite of those observed in Experiment 1: They showed a preference for the failed actions. These findings suggest that previous experience influenced the subsequent perception of others' goal-directed actions in the 12-month-old infants. We favor the interpretation that the preference for the successful actions in the 12-months-old infants provided with blindfolded experience demonstrates the influence of perceptual experience on considering the visual status of others engaging in goal-directed actions. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Object segregation in 8-month-old infants

Two experiments examined 8-month-old infants' use of configural and physical knowledge in segregating three-dimensional adjacent displays. The infants in Experiment I saw two identical yellow octagons standing side by side: in the test events, a hand grasped the right octagon and pulled it to the side. The infants looked reliably longer when the octagons moved apart than when they moved together, suggesting that the infants (a) perceived the octagons as a single unit and hence (b) expected them to move together and were surprised when they did not. The infants in Experiment 2 saw a yellow cylinder and a blue box: a hand grasped the cylinder and pulled it to the side. The infants looked reliably longer when the box moved with the cylinder than when the box remained in place, suggesting that they (a) viewed the cylinder and box as distinct units and thus (b) expected the cylinder to move alone and were surprised when it did not. These results indicate that, by 8 months of age, infants use configural knowledge when organizing adjacent displays: they expect similar parts to belong to the same unit and dissimilar parts to belong to distinct units. Additional results revealed that 8-month-old infants' interpretation of displays is affected not only by configural but also by physical consideration. Thus, infants in Experiment 1 who saw a thin blade lowered between the octagons viewed them as two rather than as one unit. Similarly, infants in Experiment 2 who saw the cylinder lying above instead of on the apparatus floor perceived the cylinder and box as one rather than two units. These results indicate that 8-month-old infants bring to bear their knowledge of impenetrability and support when parsing adjacent displays. Furthermore, when faced with two conflicting interpretations of a display, one suggested by their configural and one by their physical knowledge, infants allow the latter to supersede the former. Together, these findings suggest that, by 8 months of age infants approach to segregation is fundamentally similar to that of adults.     

Mother–infant responsiveness: Timing, mutual regulation, and interactional context.

Mutual regulation during the naturalistic interaction of 150 mothers and their 4-month-old infants was investigated from a dynamic systems perspective. Microanalyses of a wide range of behaviors and analysis of contingencies indicated that a 3-sec time period best captured contingencies. Both mothers and infants communicated primarily through vocal signals and responses, although maternal touches and infant looks also elicited responses. Although more expressive mothers did not have infants who behaved similarly, levels of contingent responsiveness between partners were significantly associated and occurred within distinct behavioral channels, suggesting coregulated interactional processes in which contingently responsive mothers shape their infants' communications toward mutual similarity. Mothers were more influential than infants over object play, whereas infants were more influential than mothers over expressive behavior. Interactional context consistently influenced contingent responsiveness; there was less mutual responsiveness when the infant was exploring, being held, or looking. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of the symmetrical patterning of human gait by infants.

Two experiments tested 3- and 5-month-old infants' sensitivity to properties of point-light displays of human gait. In Experiment 1, infants were tested for discrimination of point-light displays of a walker and a runner, which, although they differed in many ways, were equivalent with regard to the phasing of limb movements. Results revealed that 3-month-old, but not 5-month-old, infants discriminated these displays. In Experiment 2, the symmetrical phase-patterning of the runner display was perturbed by advancing two of its limbs by 25% of the gait cycle. Both 3- and 5-month-old infants discriminated the walker display from this new phase-shifted runner display. These findings suggest that 3-month-old infants respond to the absolute and relative motions within a single limb, whereas 5-month-old infants respond primarily to the relations between limbs and, in particular, to the bilateral symmetry between the limbs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visual experience enhances infants' use of task-relevant information in an action task.

Four experiments examined whether infants' use of task-relevant information in an action task could be facilitated by visual experience in the laboratory. Twelve- but not 9-month-old infants spontaneously used height information and chose an appropriate (taller) cover in search of a hidden tall toy. After watching examples of covering events in a teaching session, 9-month-old infants succeeded in an action task that involved the same event category; learning was not generalized to events from a different category. The present results demonstrate that learning through visual experience can be transferred to infants' subsequent actions. These findings shed light on the link between perception and action in infancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mother's insightfulness regarding their infants' internal experience: Relations with maternal sensitivity and infant attachment.

This study examined the associations among mothers' insightfulness into their infants' internal experience, mothers' sensitivity to their infants' signals, and infants' security of attachment to their mothers. The insightfulness of 129 mothers of 12-month-old infants was assessed by showing mothers 3 videotaped segments of observations of their infants and themselves and interviewing them regarding their infants' and their own thoughts and feelings. Interviews were classified into 1 insightful and 3 noninsightful categories. Mothers' sensitivity was assessed during play sessions at home and at the laboratory, and infant-mother attachment was assessed with the Strange Situation. Mothers classified as positively insightful were rated as more sensitive and were more likely to have securely attached children than were mothers not classified as positively insightful. Insightfulness also accounted for variance in attachment beyond the variance explained by maternal sensitivity. These findings add an important dimension to research on caregiving, suggesting that mothers' seeking of explanations for the motives underlying their infants' behavior is related to both maternal sensitivity and infant attachment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Learning about tools in infancy.

These experiments explored the role of prior experience in 12- to 18-month-old infants' tool-directed actions. In Experiment 1, infants' use of a familiar tool (spoon) to accomplish a novel task (turning on lights inside a box) was examined. Infants tended to grasp the spoon by its handle even when doing so made solving the task impossible (the bowl did not fit through the hole in the box, but the handle did) and even though the experimenter demonstrated a bowl-grasp. In contrast, infants used a novel tool flexibly and grasped both sides equally often. In Experiment 2, infants received training using the novel tool for a particular function; 3 groups of infants were trained to use the tool differently. Later, infants' performance was facilitated on tasks that required infants to grasp the part of the tool they were trained to grasp. The results suggest that (a) infants' prior experiences with tools are important to understanding subsequent tool use, and (b) rather than learning about tool function (e.g., hammering), infants learn about which part of the tool is meant to be held, at least early in their exposure to a novel tool. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' ability to parse continuous actions.

In a series of 3 experiments, the authors examined 6- and 8-month-old infants' capacities to detect target actions in a continuous action sequence. In Experiment 1, infants were habituated to 2 different target actions and subsequently were presented with 2 continuous action sequences that either included or did not include the familiar target actions. Infants looked significantly longer at the sequences that were novel. Experiment 2 presented the habituation and test trials in the reverse order. The results showed that infants habituated to the sequence still showed reliable evidence of recognizing the target action during the test trials. Experiment 3 was comparable to Experiment 2, except it tested whether infants could detect a different event segment, namely the transitions between events. The results showed that infants did not discriminate between test trials suggesting that transitions between events are not as easy for infants to recognize. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social cognition, joint attention, and communicative competence from 9 to 15 months of age

At around 1 year of age, human infants display a number of new behaviors that seem to indicate a newly emerging understanding of other persons as intentional beings whose attention to outside objects may be shared, followed into, and directed in various ways. These behaviors have mostly been studied separately. In the current study, we investigated the most important of these behaviors together as they emerged in a single group of 24 infants between 9 and 15 months of age. At each of seven monthly visits, we measured joint attentional engagement, gaze and point following, imitation of two different kinds of actions on objects, imperative and declarative gestures, and comprehension and production of language. We also measured several nonsocial-cognitive skills as a point of comparison. We report two studies. The focus of the first study was the initial emergence of infants' social-cognitive skills and how these skills are related to one another developmentally. We found a reliable pattern of emergence: Infants progressed from sharing to following to directing others' attention and behavior. The nonsocial skills did not emerge predictably in this developmental sequence. Furthermore, correlational analyses showed that the ages of emergence of all pairs of the social-cognitive skills or their components were inter-related. The focus of the second study was the social interaction of infants and their mothers, especially with regard to their skills of joint attentional engagement (including mothers' use of language to follow into or direct infants' attention) and how these skills related to infants' early communicative competence. Our measures of communicative competence included not only language production, as in previous studies, but also language comprehension and gesture production. It was found that two measures--the amount of time infants spent in joint engagement with their mothers and the degree to which mothers used language that followed into their infant's focus of attention--predicted infants' earliest skills of gestural and linguistic communication. Results of the two studies are discussed in terms of their implications for theories of social-cognitive development, for theories of language development, and for theories of the process by means of which human children become fully participating members of the cultural activities and processes into which they are born.     

Infant discrimination of faces in naturalistic events: Actions are more salient than faces.

Despite the fact that faces are typically seen in the context of dynamic events, there is little research on infants' perception of moving faces. L. E. Bahrick, L. J. Gogate, and I. Ruiz (2002) demonstrated that 5-month-old infants discriminate and remember repetitive actions but not the faces of the women performing the actions. The present research tested an attentional salience explanation for these findings: that dynamic faces are discriminable to infants, but more salient actions compete for attention. Results demonstrated that 5-month-old infants discriminated faces in the context of actions when they had longer familiarization time (Experiment 1) and following habituation to a single person performing 3 different activities (Experiment 2). Further, 7-month-old infants who have had more experience with social events also discriminated faces in the context of actions. Overall, however, discrimination of actions was more robust and occurred earlier in processing time than discrimination of dynamic faces. These findings support an attentional salience hypothesis and indicate that faces are not special in the context of actions in early infancy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Mother-child play and emerging social behaviors among infants from maltreating families.

Mother-child play of 12-month-old infants (N = 130) from maltreating (N = 78) and nonmaltreating (N = 52) families was analyzed as a context that integrates infants' developing social and cognitive skills. Play was coded from semistructured and unstructured play paradigms. No group differences were found in infants' play maturity. Infants from abusing families demonstrated more imitative play than infants from nonmaltreating families, and engaged in less independent play than infants from both neglecting and nonmaltreating families, suggesting a delay in emerging social behaviors. Mothers from abusing and nonmaltreating families differed in attention directing behaviors. Maternal behaviors predicted child play style variables, but did not mediate the effects of maltreatment. Findings discuss the influence of an early maltreating environment upon the development of the emergent self. Implications for early intervention are underscored. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Is Helicobacter pylori really the cause of gastric cancer?

The goal of this study was to assess the role of examining and repetitive rhythmic activity in infants' exploration of novel objects. Sixteen 8-month-old infants played with novel toys as auditory-visual slide distractors occurred on one side at random intervals. The results showed that examining, but not repetitive activities, declined with exposure to the objects. They also showed that infants had different patterns of distractibility during examining and repetitive rhythmic activities. The infants were slower to turn to the distractor if they were examining the toy than if they were engaged in other activity, but the probability of a response did not differ. In contrast, when engaged in repetitive rhythmic activity, infants were less likely to respond to the distractor than when engaged in other activities, including examining; the speed with which they responded, however, did not differ. The results suggest that, during these two activities, the mechanisms for resisting distraction are quite different.     

Learning and discrimination of audiovisual events in human infants: The hierarchical relation between intersensory temporal synchrony and rhythmic pattern cues.

This study examined 4- to 10-month-old infants' perception of audio-visual (A-V) temporal synchrony cues in the presence or absence of rhythmic pattern cues. Experiment 1 established that infants of all ages could successfully discriminate between two different audiovisual rhythmic events. Experiment 2 showed that only 10-month-old infants detected a desynchronization of the auditory and visual components of a rhythmical event. Experiment 3 showed that 4- to 8-month-old infants could detect A-V desynchronization but only when the audiovisual event was nonrhythmic. These results show that initially in development infants attend to the overall temporal structure of rhythmic audiovisual events but that later in development they become capable of perceiving the embedded intersensory temporal synchrony relations as well. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' Vagal Regulation in the Still-Face Paradigm Is Related to Dyadic Coordination of Mother-Infant Interaction.

The authors investigated relations between mother-infant dyadic coordination and infants' physiological responses. Mothers (N=73) and 3-month-old male and female infants were observed in the still-face paradigm, and mothers' and infants' affective states were coded at 1-s intervals. Synchrony and levels of matching between mother-infant affective states were computed, and infants' heart rate and vagal tone were measured. Infants showed increased negative affect and heart rate and decreased vagal tone during mothers' still-face, indicating physiological regulation of distress. Infants who did not suppress vagal tone during the still-face (nonsuppressors) showed less positive affect, higher reactivity and vagal suppression in normal play and reunion episodes, and lower synchrony in normal play with mothers. The results indicate that infants' physiological regulation in social interaction differs in relation to dyadic coordination of affective behaviors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perception of biomechanical motions by infants: Implementation of various processing constraints.

Geometry informs us that there exist a large number of possible connectivity patterns consistent with a point-light display of a person walking. Yet there is only one pattern consistent with a "stick figure" representation of the human form, and that pattern is uniquely specified by those pairwise connections that remain locally rigid. In this study, sensitivity to local rigidity in biomechanical displays was investigated in 3- and 5-month-old infants. The results of Experiment 1 revealed that by 5 months of age, infants discriminate a locally rigid point-light walker display from one in which local rigidity is perturbed. In Experiment 2 we tested infants' sensitivity to the same stimuli when those stimuli were inverted. Contrary to the preceding experiment, the results revealed no evidence of discrimination. Taken together, these findings suggest that infants are sensitive to local rigidity in biomechanical displays but that this sensitivity is orientation specific. Possible mechanisms for this specificity are discussed in the context of additional constraints on the processing of biomechanical displays. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of location memory in 8-month-old infants in a nonsearch AB task.

Recent studies have shown that when an object is hidden in a location A and then in a location B, 8-month-old infants tend to search in A if forced to wait 3 s before retrieving the object, and to search randomly in A or B if forced to wait 6 s before retrieving the object (e.g., Diamond, 1985). A non-search method was devised to examine 8-month-olds' ability to remember the location of a hidden object. The infants saw an object standing on one of two placemats located on either side of the midline. Next, screens were pushed in front of the placemats, hiding the object from view. After 15 s, a hand reached behind one of the screens and reappeared holding the object. The infants looked reliably longer when the hand retrieved the object from behind the "wrong" as opposed to the "right" screen (where the object was actually hidden). This result suggests that the infants (a) remembered the object's location during the 15-s delay and (b) were surprised to see the object retrieved from behind the right (left) screen when they had last seen it on the left (right) placemat. These results indicate that 8-month-old infants' ability to remember the location of a hidden object is far better than their performance in the AB search task suggests. As such, the present results cast serious doubts on accounts that attribute infants' perseverative and/or random search errors to limited memory mechanisms. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Infants' acquisition of spatiotemporal expectations.

The microdevelopment of infants' visual expectations was examined by analysis of the eye movements that 80 three-month-old human infants made during interstimulus intervals (ISIs) of an alternating picture sequence. For comparison, identical eye movement data were gathered from 10 infants who watched an irregular sequence. Shifts during ISIs were exhibited by all infants and occurred on 48% of all trials. Initially, infants' ISI shifts repeated saccades that had successfully located the preceding picture; during the course of the alternating session, repetitive saccades declined while alternating and anticipatory saccades increased. For infants who saw the irregular sequence, the frequency of ISI shifts did not vary systematically over trials. Analysis of saccade latencies suggested that infants quickly learned to inhibit a prepotent tendency in order to execute task-appropriate saccades. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The development of calibration-based reasoning about collision events in young infants

Previous research indicates that, when shown a collision between a moving and a stationary object, 11-month-old infants believe that the size of the moving object affects how far the stationary object is displaced. The present experiments examined whether 6.5- and 5.5-month-old infants hold the same belief. The infants sat in front of a horizontal track; to the left of the track was an inclined ramp. A wheeled toy bug rested on the track at the bottom of the ramp. The infants were habituated to an event in which a medium-size cylinder rolled down the ramp and hit the bug, propelling it to the middle of the track. Next, the infants saw two test events in which novel cylinders propelled the bug to the end of the track. The two novel cylinders were identical to the habituation cylinder in material but not in size: one was larger (large-cylinder event) and one was smaller (small-cylinder event) than the habituation cylinder. The 6.5-month-old infants, and the 5.5-month-old female infants, looked reliably longer at the small- than at the large-cylinder event. These and control results indicated that the infants (a) believed that the size of the cylinder affected the length of the bug's trajectory and (b) used the habituation event to calibrate their predictions about the test events. Unlike the other infants, the 5.5-month-old male infants tended to look equally at the small- and large-cylinder events. Further results indicated that this negative finding was not due to the infants' (a) failure to remember how far the bug rolled in the habituation event or (b) inability to use the habituation event to calibrate predictions about novel test events. Together, the present results suggest the following conclusions. First, when shown a collision between a moving and a stationary object, infants aged 5.5-6.5 months (a) believe that there is a proportional relation between the size of the moving object and the distance traveled by the stationary object and (b) can engage in calibration-based reasoning about this size/distance relation. Second, female infants precede males by a few weeks in this development, for reasons that may be related to sex differences in the maturation of depth perception.