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Parent language input is a well-established predictor of child language development. Multisensory attention skills (MASks; intersensory matching, shifting and sustaining attention to audiovisual speech) are also known to be foundations for language development. However, due to a lack of appropriate measures, individual differences in these skills have received little research focus. A newly established measure, the Multisensory Attention Assessment Protocol (MAAP), allows researchers to examine predictive relations between early MASks and later outcomes. We hypothesized that, along with parent language input, multisensory attention to social events (faces and voices) in infancy would predict later language outcomes. We collected data from 97 children (predominantly White and Hispanic, 48 males) participating in an ongoing longitudinal study assessing 12-, 18-, and 24-month MASks (MAAP) and parent language input (quality, quantity), and 18- and 24-month language outcomes (child speech production, vocabulary size). Results revealed 12-month intersensory matching (but not maintaining or shifting attention) of faces and voices in the presence of a distractor was a strong predictor of language. It predicted a variety of 18- and 24-month child language outcomes (expressive vocabulary, child speech production), even when holding traditional predictors constant: parent language input and SES (maternal education: 52% bachelor's degree or higher). Further, at each age, parent language input predicted just one outcome, expressive vocabulary, and SES predicted child speech production. These novel findings reveal infant intersensory matching of faces and voices in the presence of a distractor can predict which children might benefit most from parent language input and show better language outcomes. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Attention is a state of readiness or alertness, associated with behavioral and psychophysiological responses, that facilitates learning and memory. Multisensory and dynamic events have been shown to elicit more attention and produce greater sustained attention in infants than auditory or visual events alone. Such redundant and often temporally synchronous information guides selectivity and facilitates perception, learning, and memory of properties of events specified by redundancy. In addition, events involving faces or other social stimuli provide an extraordinary amount of redundant information that attracts and sustains attention. In the current study, 4- and 8-month-old infants were shown 2-min multimodal videos featuring social or nonsocial stimuli to determine the relative roles of synchrony and stimulus category in inducing attention. Behavioral measures included average looking time and peak look duration, and convergent measurement of heart rate (HR) allowed for the calculation of HR-defined phases of attention: Orienting (OR), sustained attention (SA), and attention termination (AT). The synchronous condition produced an earlier onset of SA (less time in OR) and a deeper state of SA than the asynchronous condition. Social stimuli attracted and held attention (longer duration of peak looks and lower HR than nonsocial stimuli). Effects of synchrony and the social nature of stimuli were additive, suggesting independence of their influence on attention. These findings are the first to demonstrate different HR-defined phases of attention as a function of intersensory redundancy, suggesting greater salience and deeper processing of naturalistic synchronous audiovisual events compared with asynchronous ones.

Research on infants' perception and memory for social information are discussed with respect to the concept of ecological validity. We argue that the use of dynamic, multimodal displays in familiar contexts is critical to understanding infants' developing perception. We also discuss the importance of generalizing appropriately from experimental to real-world contexts and of using converging methods in the investigation of infants' capabilities.

Detecting intersensory redundancy guides cognitive, social, and language development. Yet, researchers lack fine-grained, individual difference measures needed for studying how early intersensory skills lead to later outcomes. The intersensory processing efficiency protocol (IPEP) addresses this need. Across a number of brief trials, participants must find a sound-synchronized visual target event (social, nonsocial) amid five visual distractor events, simulating the "noisiness" of natural environments. Sixty-four 3- to 5-year-old children were tested using remote eye-tracking. Children showed intersensory processing by attending to the sound-synchronous event more frequently and longer than in a silent visual control, and more frequently than expected by chance. The IPEP provides a fine-grained, nonverbal method for characterizing individual differences in intersensory processing appropriate for infants and children. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Multisensory attention skills provide a crucial foundation for early cognitive, social, and language development, yet there are no fine-grained, individual difference measures of these skills appropriate for preverbal children. The Multisensory Attention Assessment Protocol (MAAP) fills this need. In a single video-based protocol requiring no language skills, the MAAP assesses individual differences in three fundamental building blocks of attention to multisensory events-the duration of attention maintenance, the accuracy of intersensory (audiovisual) matching, and the speed of shifting-for both social and nonsocial events, in the context of high and low competing visual stimulation. In Experiment 1, 2- to 5-year-old children (N = 36) received the MAAP and assessments of language and cognitive functioning. In Experiment 2 the procedure was streamlined and presented to 12-month-olds (N = 48). Both infants and children showed high levels of attention maintenance to social and nonsocial events, impaired attention maintenance and speed of shifting when competing stimulation was high, and significant intersensory matching. Children showed longer maintenance, faster shifting, and less impairment from competing stimulation than infants. In 2- to 5-year-old children, duration and accuracy were intercorrelated, showed increases with age, and predicted cognitive and language functioning. The MAAP opens the door to assessing developmental pathways between early attention patterns to audiovisual events and language, cognitive, and social development. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Selective attention to different properties of stimulation provides the foundation for perception, learning, and memory. The Intersensory Redundancy Hypothesis (IRH) proposes that early in development information presented redundantly across two or more modalities (multimodal) selectively recruits attention to and enhances perceptual learning of amodal properties, whereas information presented to a single sense modality (unimodal) enhances perceptual learning of modality-specific properties. The present study is the first to assess this principle of unimodal facilitation in non-human animals in prenatal development. We assessed bobwhite quail embryos’ prenatal detection of pitch, a modality-specific property, under conditions of unimodal and bimodal (synchronous or asynchronous) exposure. Chicks exposed to prenatal unimodal auditory stimulation or asynchronous bimodal (audiovisual) stimulation preferred the familiarized maternal call over a novel pitch-modified maternal call following hatching, whereas chicks exposed to redundant (synchronous) audiovisual stimulation failed to prefer the familiar call over the pitch-modified call. These results provide further evidence that selective attention is recruited to specific stimulus properties of events in early development and that these biases are evident even during the prenatal period.

The development of attention to dynamic faces versus objects providing synchronous audiovisual versus silent visual stimulation was assessed in a large sample of infants. Maintaining attention to the faces and voices of people speaking is critical for perceptual, cognitive, social, and language development. However, no studies have systematically assessed when, if, or how attention to speaking faces emerges and changes across infancy. Two measures of attention maintenance, habituation time (HT) and look-away rate (LAR), were derived from cross-sectional data of 2- to 8-month-old infants (N = 801). Results indicated that attention to audiovisual faces and voices was maintained across age, whereas attention to each of the other event types (audiovisual objects, silent dynamic faces, silent dynamic objects) declined across age. This reveals a gradually emerging advantage in attention maintenance (longer HTs, lower LARs) for audiovisual speaking faces compared with the other 3 event types. At 2 months, infants showed no attentional advantage for faces (with greater attention to audiovisual than to visual events); at 3 months, they attended more to dynamic faces than objects (in the presence or absence of voices), and by 4 to 5 and 6 to 8 months, significantly greater attention emerged to temporally coordinated faces and voices of people speaking compared with all other event types. Our results indicate that selective attention to coordinated faces and voices over other event types emerges gradually across infancy, likely as a function of experience with multimodal, redundant stimulation from person and object events. (PsycINFO Database Record

Principles of a dynamic, dyadic systems view of mother-infant face-to-face communication, which considers self- and interactive processes in relation to one another, were tested. We examined the process of interaction across time in a large, low-risk community sample, at infant age 4 months. Split-screen videotape was coded on a 1-s time base for communication modalities of attention, affect, orientation, touch and composite facial-visual engagement. Time-series approaches generated self- and interactive contingency estimates in each modality. Evidence supporting the following principles was obtained: (1) Significant moment-to-moment predictability within each partner (self-contingency) and between the partners (interactive contingency) characterizes mother-infant communication. (2) Interactive contingency is organized by a bi-directional, but asymmetrical, process: maternal contingent coordination with infant is higher than infant contingent coordination with mother. (3) Self-contingency organizes communication to a far greater extent than interactive contingency. (4) Self-and interactive contingency processes are not separate; each affects the other, in communication modalities of facial affect, facial-visual engagement, and orientation. Each person’s self-organization exists in a dynamic, homoeostatic (negative feedback) balance with the degree to which the person coordinates with the partner. For example, those individuals who are less facially stable are likely to coordinate more strongly with the partner’s facial affect; and vice-versa. Our findings support the concept that the dyad is a fundamental unit of analysis in the investigation of early interaction. Moreover, an individual’s self-contingency is influenced by the way the individual coordinates with the partner. Our results imply that it is not appropriate to conceptualize interactive processes without simultaneously accounting for dynamically inter-related self-organizing processes.

Research examining infants' discrimination of affect often uses unfamiliar faces and voices of adults. Recently, research has examined infant discrimination of affect in familiar faces and voices. In much of this research, infants were habituated to the affective expressions using a "standard" 50% habituation criterion. We extend this line of research by examining infants' discrimination of unfamiliar peers', that is, 4-month-olds, dynamic, facial, and vocal affective expressions and assessing how discrimination is affected by changing the habituation criterion. In two experiments, using an infant-controlled habituation design, we explored 3- and 5-month-olds' discrimination of their peers' dynamic audiovisual displays of positive and negative expressions of affect. Results of Experiment 1, using a 50% habituation criterion, revealed that 5-month-olds, but not 3-month-olds discriminated the affective expressions of their peers. In Experiment 2, we examined whether 3-month-olds' lack of discrimination in Experiment 1 was a result of insufficient habituation (i.e., familiarization). Specifically, 3-month-olds were habituated using a 70% habituation criterion, providing them with longer familiarization time. Results revealed that using the more stringent habituation criterion, 3-month-olds showed longer habituation times, that is increased familiarization, and discriminated their peers' affective expressions. Results are discussed in terms of infants' discrimination of affect, the role of familiarization time, and limitations of the 50% habituation criterion.

Prosody, or the intonation contours of speech, conveys emotion and intention to the listener and provides infants with an early basis for detecting meaning in speech. Infant-directed speech (IDS) is characterized by exaggerated prosody, slower tempo, and elongated pauses, all amodal properties detectable across the face and voice. Although speech is an audiovisual event, it has been studied primarily as a unimodal auditory stream without the synchronized dynamic face of the speaker. According to the intersensory redundancy hypothesis, redundancy across the senses facilitates perceptual learning of amodal information, including prosody. We predicted that young infants who are still learning to discriminate and categorize prosodic information would detect prosodic changes better in the presence of intersensory redundancy (i.e., synchronous audiovisual speech) than in its absence (i.e., unimodal auditory or asynchronous audiovisual speech). To test this hypothesis, 72 4-month-old infants were habituated to recordings of women reciting passages in IDS with prosody conveying either approval or prohibition and then were tested with recordings of a novel passage with either a change or no change in prosody. Infants who received bimodal synchronous stimulation exhibited significant visual recovery to the novel passage with a change in prosody, but not to a novel passage with no change in prosody. Infants in the unimodal auditory and bimodal asynchronous conditions did not exhibit visual recovery in either condition. Results support the hypothesis that intersensory redundancy facilitates detection and abstraction of invariant prosody across changes in linguistic content and likely serves as an early foundation for the detection of meaning in fluent speech.

Although looking time is used to assess infant perceptual and cognitive processing, little is known about the temporal structure of infant looking. To shed light on this temporal structure, 127 three-month-olds were assessed in an infant-controlled habituation procedure and presented with a pre-recorded display of a woman addressing the infant using infant-directed speech. Previous individual look durations positively predicted subsequent look durations over a six look window, suggesting a temporal dependency between successive infant looks. The previous look duration continued to predict the subsequent look duration after accounting for habituation-linked declines in look duration, and when looks were separated by an inter-trial interval in which no stimulus was displayed. Individual differences in temporal dependency, the strength of associations between consecutive look durations, are distinct from individual differences in mean infant look duration. Nevertheless, infants with stronger temporal dependency had briefer mean look durations, a potential index of stimulus processing. Temporal dependency was evident not only between individual infant looks but between the durations of successive habituation trials (total looking within a trial). Finally, temporal dependency was evident in associations between the last look at the habituation stimulus and the first look at a novel test stimulus. Thus temporal dependency was evident across multiple timescales (individual looks and trials comprised of multiple individual looks) and persisted across conditions including brief periods of no stimulus presentation and changes from a familiar to novel stimulus. Associations between consecutive look durations over multiple timescales and stimuli suggest a temporal structure of infant attention that has been largely ignored in previous work on infant looking.

Selective attention is the gateway to perceptual processing, learning, and memory and is a skill honed through extensive experience. However, little research has focused on how selective attention develops. Here, we synthesize established and new findings from studies assessing the central role of redundancy across the senses in guiding and constraining this process in infancy and early childhood. We highlight research demonstrating the dual role of intersensory redundancy—its facilitating and interfering effects—in the detection and perceptual processing of various properties of objects and events.

Although infants and children show impressive face processing skills, little research has focused on the conditions that facilitate versus impair face perception. According to the Intersensory Redundancy Hypothesis (IRH), face discrimination, which relies on detection of visual featural information, should be impaired in the context of intersensory redundancy provided by audiovisual speech and enhanced when intersensory redundancy is absent. Evidence of this visual facilitation and intersensory interference was found in a recent study of 2-month-old infants (Bahrick, Lickliter, & Castellanos, in press). The present study is the first to extend tests of this principle of the IRH to children. Using a more difficult face recognition task in the context of a story, results from 4-year old children paralleled those of infants and demonstrate that face discrimination in children is also facilitated by dynamic, visual-only exposure, in the absence of intersensory redundancy.

Research has demonstrated that infants recognize emotional expressions of adults in the first half year of life. We extended this research to a new domain, infant perception of the expressions of other infants. In an intermodal matching procedure, 3.5- and 5-month-old infants heard a series of infant vocal expressions (positive and negative affect) along with side-by-side dynamic videos in which one infant conveyed positive facial affect and another infant conveyed negative facial affect. Results demonstrated that 5-month-olds matched the vocal expressions with the affectively congruent facial expressions, whereas 3.5-month-olds showed no evidence of matching. These findings indicate that by 5 months of age, infants detect, discriminate, and match the facial and vocal affective displays of other infants. Further, because the facial and vocal expressions were portrayed by different infants and shared no face–voice synchrony, temporal, or intensity patterning, matching was likely based on detection of a more general affective valence common to the face and voice.

Two experiments assessing event-related potentials in 5-month-old infants were conducted to examine neural correlates of attentional salience and efficiency of processing of a visual event (woman speaking) paired with redundant (synchronous) speech, nonredundant (asynchronous) speech, or no speech. In Experiment 1, the Nc component associated with attentional salience was greater in amplitude following synchronous audiovisual as compared with asynchronous audiovisual and unimodal visual presentations. A block design was utilized in Experiment 2 to examine efficiency of processing of a visual event. Only infants exposed to synchronous audiovisual speech demonstrated a significant reduction in amplitude of the late slow wave associated with successful stimulus processing and recognition memory from early to late blocks of trials. These findings indicate that events that provide intersensory redundancy are associated with enhanced neural responsiveness indicative of greater attentional salience and more efficient stimulus processing as compared with the same events when they provide no intersensory redundancy in 5-month-old infants.

Although research has demonstrated impressive face perception skills of young infants, little attention has focused on conditions that enhance versus impair infant face perception. The present studies tested the prediction, generated from the Intersensory Redundancy Hypothesis (IRH), that face discrimination, which relies on detection of visual featural information, would be impaired in the context of intersensory redundancy provided by audiovisual speech, and enhanced in the absence of intersensory redundancy (unimodal visual and asynchronous audiovisual speech) in early development. Later in development, following improvements in attention, faces should be discriminated in both redundant audiovisual and nonredundant stimulation. Results supported these predictions. Two-month-old infants discriminated a novel face in unimodal visual and asynchronous audiovisual speech but not in synchronous audiovisual speech. By 3 months, face discrimination was evident even during synchronous audiovisual speech. These findings indicate that infant face perception is enhanced and emerges developmentally earlier following unimodal visual than synchronous audiovisual exposure and that intersensory redundancy generated by naturalistic audiovisual speech can interfere with face processing.

Prenatal experience is both a formative and regulatory force in the process of development. As a result, birth is not an adequate starting point for explanations of behavioral development. However, little is currently known regarding the role of prenatal experience in the emergence and development of neonatal social orienting, social motivation, or social learning. Our lack of knowledge in this area is due in part to the very restricted experimental manipulations possible with human fetuses. A comparative approach utilizing animal models provides an essential step in addressing this gap in our knowledge of the development of social responsiveness and providing testable predictions for studies with human fetuses and infants. In this chapter we review animal-based research exploring how aspects of prenatal experience can facilitate the development of postnatal social motivation, social recognition, and social learning. We conclude that infant social responsiveness has its roots in prenatal development and that intersensory redundancy present in the prenatal environment promotes the salience of social stimuli during early postnatal development.

A microanalysis of 4-month mother-infant face-to-face communication predicted 12-month infant disorganized (vs. secure) attachment outcomes in an urban community sample. We documented a dyadic systems view of the roles of both partners, the roles of both self- and interactive contingency, and the importance of attention, orientation and touch, and as well as facial and vocal affect, in the co-construction of attachment disorganization. The analysis of different communication modalities identified striking intrapersonal and interpersonal intermodal discordance or conflict, in the context of intensely distressed infants, as the central feature of future disorganized dyads at 4 months. Lowered maternal contingent coordination, and failures of maternal affective correspondence, constituted maternal emotional withdrawal from distressed infants. This maternal withdrawal compromises infant interactive agency and emotional coherence. We characterize of the nature of emerging internal working models of future disorganized infants as follows: Future disorganized infants represent states of not being sensed and known by their mothers, particularly in moments of distress; they represent confusion about both their own and their mothers’ basic emotional organization, and about their mothers’ response to their distress. This internal working model sets a trajectory in development which may disturb the fundamental integration of the person. The remarkable specificity of our findings has the potential to lead to more finely-focused clinical interventions.

Despite important recent progress in understanding disorganized attachment, we still lack a full understanding of the mechanisms of disorganized attachment formation and transmission prior to 12 months. In this paper we lay out our recommendations for the study of the 4-month origins of disorganized attachment. In our subsequent Paper II we report on the results of a large empirical study that was conducted along the lines we recommend in Paper I. Both Papers I and II are based on Beebe, Jaffe, Markese, Buck, Chen, Cohen, Bahrick, Andrews, Feldstein (2010). In Paper I we describe our proposal that a detailed microanalysis of 4-month mother-infant face-to-face communication would further inform our understanding of the process of disorganized attachment formation between mother and infant. Such a microanalysis would allow us to characterize the nature of the 4-month infant’s procedural representations, or emerging “internal working models” of attachment.

Early evidence of social referencing was examined in 5 ½-month-old infants. Infants were habituated to two films of moving toys, one toy eliciting a woman's positive emotional expression and the other eliciting a negative expression under conditions of bimodal (audiovisual) or unimodal visual (silent) speech. It was predicted that intersensory redundancy provided by audiovisual (but not available in unimodal visual) events would enhance detection of the relation between emotional expressions and the corresponding toy. Consistent with predictions, only infants who received bimodal, audiovisual events detected a change in the affect-object relations, showing increased looking during a switch test in which the toy-affect pairing was reversed. Moreover, in a subsequent live preference test, they preferentially touched the 3-dimensional toy previously paired with the positive expression. These findings suggest social referencing emerges by 5 ½ months of age in the context of intersensory redundancy provided by dynamic multimodal stimulation and that even 5 ½-month-old infants demonstrate preferences for 3-dimensional objects based on affective information depicted in videotaped events.

Prior research has demonstrated intersensory facilitation for perception of amodal properties of events such as tempo and rhythm in early development, supporting predictions of the Intersensory Redundancy Hypothesis (IRH). Specifically, infants discriminate amodal properties in bimodal, redundant stimulation but not in unimodal, nonredundant stimulation in early development, whereas later in development infants can detect amodal properties in both redundant and nonredundant stimulation. The present study tested a new prediction of the IRH: that effects of intersensory redundancy on attention and perceptual processing are most apparent in tasks of high difficulty relative to the skills of the perceiver. We assessed whether by increasing task difficulty, older infants would revert to patterns of intersensory facilitation shown by younger infants. Results confirmed our prediction and demonstrated that in difficult tempo discrimination tasks, 5-month-olds perform like 3-month-olds, showing intersensory facilitation for tempo discrimination. In contrast, in tasks of low and moderate difficulty, 5-month-olds discriminate tempo changes in both redundant audiovisual and nonredundant unimodal visual stimulation. These findings indicate that intersensory facilitation is most apparent for tasks of relatively high difficulty and may therefore persist across the lifespan.

We explored the amount and timing of temporal synchrony necessary to facilitate prenatal perceptual learning using an animal model, the bobwhite quail. Quail embryos were exposed to various audiovisual combinations of a bobwhite maternal call paired with patterned light during the late stages of prenatal development and were tested postnatally for evidence of prenatal auditory learning of the familiarized call. Results revealed that a maternal call paired with a single pulse of light synchronized with one note of the five note call was sufficient to facilitate embryos’ prenatal perceptual learning of the entire call. A synchronous note occurring at the onset of the call burst was most effective at facilitating learning. These findings highlight quail embryos’ remarkable sensitivity to temporal synchrony and indicate its role in promoting learning of redundantly specified stimulus properties during prenatal development.

This research examined the effects of bimodal audiovisual and unimodal visual stimulation on infants’ memory for the visual orientation of a moving toy hammer following a 5-min, 2-week, or 1-month retention interval. According to the intersensory redundancy hypothesis (L. E. Bahrick & R. Lickliter, 2000; L. E. Bahrick, R. Lickliter, & R. Flom, 2004) detection of and memory for nonredundantly specified properties, including the visual orientation of an event, are facilitated in unimodal stimulation and attenuated in bimodal stimulation in early development. Later in development, however, nonredundantly specified properties can be perceived and remembered in both multimodal and unimodal stimulation. The current study extended tests of these predictions to the domain of memory in infants of 3, 5, and 9 months of age. Consistent with predictions of the intersensory redundancy hypothesis, in unimodal stimulation, memory for visual orientation emerged by 5 months and remained stable across age, whereas in bimodal stimulation, memory did not emerge until 9 months of age. Memory for orientation was evident even after a 1-month delay and was expressed as a shifting preference, from novelty to null to familiarity, across increasing retention time, consistent with Bahrick and colleagues’ four-phase model of attention. Together, these findings indicate that infant memory for nonredundantly specified properties of events is a consequence of selective attention to those event properties and is facilitated in unimodal stimulation. Memory for nonredundantly specified properties thus emerges in unimodal stimulation, is later extended to bimodal stimulation, and lasts across a period of at least 1 month.

Gottlieb promoted the value of a developmental psychobiological systems approach to the study of human development. This approach recognizes the importance of comparative, animal-based research to advancing our understanding of the complexities and dynamics of the process of development. The major contribution of animal developmental studies is their provision of food for thought (hypotheses, not facts) about human development and general principles of development. Here we briefly describe how, guided by Gottlieb's pioneering vision, we have utilized coordinated studies of non-human animal and human infants to begin to identify patterns of selective attention and perceptual processing that are common across species in early development. Our converging findings highlight the importance of multimodal (intersensory) redundancy in guiding and constraining early perceptual learning in avian and mammalian species.

Research has demonstrated that intersensory redundancy (stimulation synchronized across multiple senses) is highly salient and facilitates processing of amodal properties in multimodal events, bootstrapping early perceptual development. The present study is the first to extend this central principle of the intersensory redundancy hypothesis (IRH) to certain types of intrasensory redundancy (stimulation synchronized within a single sense). Infants were habituated to videos of a toy hammer tapping silently (unimodal control), depicting intersensory redundancy (synchronized with a soundtrack) or intrasensory redundancy (synchronized with another visual event; light flashing or bat tapping). In Experiment 1, 2-month-olds showed both intersensory and intrasensory facilitation (with respect to the unimodal control) for detecting a change in tempo. However, intrasensory facilitation was found when the hammer was synchronized with the light flashing (different motion) but not with the bat tapping (same motion). Experiment 2 tested 3-month-olds using a somewhat easier tempo contrast. Results supported a similarity hypothesis: intrasensory redundancy between two dissimilar events was more effective than that between two similar events for promoting processing of amodal properties. These findings extend the IRH and indicate that in addition to intersensory redundancy, intrasensory redundancy between two synchronized dissimilar visual events is also effective in promoting perceptual processing of amodal event properties.

The effects of stress on mothers' recall for a major hurricane were studied. Stress was objectively defined as low, moderate, or high according to the severity of home damage. This study of 96 mothers was conducted concurrently with L. E. Bahrick, J. F. Parker, R. Fivush, and M. Levitt (1998), allowing the authors to compare child and adult recall as a function of the same stressor. There was a quadratic relationship between storm severity and total recall for adults, similar to their children. Mothers' recall increased from low to moderate severity, but recall at moderate severity did not differ from high severity. These findings help clarify the effects of stress on the amount and type of information adults recall in retrospective accounts of naturalistic, temporally extended events.

According to the intersensory redundancy hypothesis (IRH), during early development, perception of nonredundantly specified properties is facilitated in unimodal stimulation as compared with bimodal stimulation. Later in development, attention becomes more flexible and infants can detect nonredundantly specified properties in both unimodal and bimodal stimulation. This study tested these predictions by assessing the development of infants' sensitivity to the orientation of an object striking a surface, information that is nonredundantly specified in visual and in audiovisual stimulation. Infants of 3, 5, and 8 months were habituated to unimodal visual or bimodal, synchronous, audiovisual films of a hammer tapping a rhythm in 1 of 2 orientations (upward vs. downward). Results demonstrated an Age × Condition interaction, where younger infants (3 and 5 months) detected the orientation change in unimodal but not bimodal stimulation, whereas older infants (8 months) detected the change in both types of stimulation. Further, in a control study, 3-month-olds detected the orientation change when bimodal stimulation was asynchronous, demonstrating that temporal synchrony impaired performance in the bimodal condition. These findings converge with those of prior studies and support predictions of the IRH.

We examined relations among stress, children’s recall, and psychological functioning following Hurricane Andrew. Thirty-five children from mixed socioeconomic backgrounds were divided into low-, moderate-, and high-stress groups and were interviewed about the hurricane immediately after the storm and 6 years later. Our primary interest, stemming from previous work, was in the emotional and cognitive content of their recall. At the initial interviews, children who were more stressed included less positive emotion and fewer cognitive processing words and provided less free recall and less information overall. In contrast, children who initially recalled more information showed better psychological outcome immediately following the hurricane. Six years later, children who had been more stressed initially included more negative emotion and more cognitive processing words, but provided less information during free recall. Children who had initially used more positive emotion words and recalled more information showed better psychological outcome 6 years later. Implications for children’s remembering and coping with traumatic events are discussed.

This study examined the development of infants' ability to perceive, learn, and remember the unique face-voice relations of unfamiliar adults. Infants of 2, 4, and 6 months were habituated to the faces and voices of 2 same-gender adults speaking and then received test trials where the faces and voices were synchronized yet mismatched. Results indicated that 4- and 6-month-olds, but not 2-month-olds, detected the change in face-voice pairings. Two-month-olds did, however, discriminate among the faces and voices in a control study. Results of a subsequent intermodal matching procedure indicated that only the 6-month-olds showed matching and memory for the face-voice relations. These findings suggest that infants' ability to detect the arbitrary relations between specific faces and voices of unfamiliar adults emerges between 2 and 4 months of age, whereas matching and memory for these relations emerges somewhat later, perhaps between 4 and 6 months of age.

SummarySelf-perception involves integrating changes in visual, tactile, and proprioceptive stimulation from self-motion and discriminating these changes from those of other objects. Recent evidence suggests even newborns discriminate synchronous from asynchronous visual-tactile stimulation to their own body, a foundation for self-perception.

Research has demonstrated that young infants can detect a change in the tempo and the rhythm of an event when they experience the event bimodally (audiovisually), but not when they experience it unimodally (acoustically or visually). According to Bahrick and Lickliter (2000, 2002), intersensory redundancy available in bimodal, but not in unimodal, stimulation directs attention to the amodal properties of events in early development. Later in development, as infants become more experienced perceivers, attention becomes more flexible and can be directed toward amodal properties in unimodal and bimodal stimulation. The present study tested this developmental hypothesis by assessing the ability of older, more perceptually experienced infants to discriminate the tempo or rhythm of an event, using procedures identical to those in prior studies. The results indicated that older infants can detect a change in the rhythm and the tempo of an event following both bimodal (audiovisual) and unimodal (visual) stimulation. These results provide further support for the intersensory redundancy hypothesis and are consistent with a pattern of increasing specificity in perceptual development.

That the senses provide overlapping information for objects and events is no extravagance of nature. This overlap facilitates attention to critical aspects of sensory stimulation, those that are redundantly specified, and attenuates attention to nonredundantly specified stimulus properties. This selective attention is most pronounced in infancy and gives initial advantage to the perceptual processing of, learning of, and memory for stimulus properties that are redundant, or amodal (e.g., synchrony, rhythm, and intensity), at the expense of modality-specific properties (e.g., color, pitch, and timbre) that can be perceived through only one sense. We review evidence supporting this hypothesis and discuss its implications for theories of perceptual, cognitive, and social development.

Information presented concurrently and redundantly to 2 or more senses (intersensory redundancy) has been shown to recruit attention and promote perceptual learning of amodal stimulus properties in animal embryos and human infants. This study examined whether the facilitative effect of intersensory redundancy also extends to the domain of memory. We assessed bobwhite quail chicks' ability to remember and prefer an individual maternal call presented either unimodally or redundantly and synchronously with patterned light during the period prior to hatching. Embryos provided with unimodal auditory exposure failed to prefer the familiar call over a novel maternal call postnatally at 48 hr and 72 hr following exposure. In contrast, embryos provided with redundant, synchronous audiovisual stimulation significantly preferred the familiar call at 48 hr following exposure, but not at 72 hr. A second experiment provided chicks with a single 10-min refamiliarization with the familiar call at either 48 hr or 72 hr following hatching. Chicks given only unimodal auditory exposure prior to hatching did not appear to benefit from this brief postnatal refamiliarization, showing no preference for the familiar call at either 72 or 96 hr. Chicks that received redundant audiovisual stimulation prenatally showed a significant preference for the familiar call (following the brief reexpo sure 24 hr earlier) at both 72 and 96 hr of age. These results are the first to demonstrate that redundantly specified information is remembered longer and reactivated more easily than the same information presented unimodally. These findings provide further evidence of the salience of intersensory redundancy in guiding selective attention and perceptual learning during early development.

L. Bahrick and R. Lickliter (2000) proposed an intersensory redundancy hypothesis that states that information presented redundantly and in temporal synchrony across two or more sensory modalities selectively recruits infant attention and facilitates perceptual learning more effectively than does the same information presented unimodally. In support of this view, they found that 5-month-old infants were able to differentiate between two complex rhythms when they were presented bimodally, but not unimodally. The present study extended our test of the intersensory redundancy hypothesis to younger infants and to a different amodal property. Three-month-olds' sensitivity to the amodal property of tempo was investigated. Results replicated and extended those of Bahrick and Lickliter, demonstrating that infants could discriminate a change in tempo following bimodal, but not unimodal, habituation. It appears that when infants are first learning to differentiate an amodal stimulus property, discrimination is facilitated by intersensory redundancy and attenuated under conditions of unimodal stimulation.

Information presented redundantly and in temporal synchrony across sensory modalities (intersensory redundancy) selectively recruits attention and facilitates perceptual learning in human infants. This comparative study examined whether intersensory redundancy also facilitates perceptual learning prenatally. The authors assessed quail (Colinus virginianus) embryos' ability to learn a maternal call when it was (a) unimodal, (b) concurrent but asynchronous with patterned light, or (c) redundant and synchronous with patterned light. Chicks' preference for the familiar over a novel maternal call was assessed 24 hr following hatching. Chicks receiving redundant, synchronous stimulation as embryos learned the call 4 times faster than those who received unimodal exposure. Chicks who received asynchronous bimodal stimulation showed no evidence of learning. These results provide the first evidence that embryos are sensitive to redundant, bimodal information and that it can facilitate learning during the prenatal period.

In a quasi-experimental study, twenty-four Asian-Indian mothers were asked to teach novel (target) names for two objects and two actions to their children of three different levels of lexical-mapping development, pre-lexical (5–8 months), early-lexical (9–17 months), and advanced-lexical (20–43 months). Target (N = 1482) and non-target (other, N = 2411) naming was coded for synchronous spoken words and object motion (multimodal motherese) and other naming styles. Indian mothers abundantly used multimodal motherese with target words to highlight novel word-referent relations, paralleling earlier findings from American mothers (Gogate, Bahrick, & Watson, 2000). They used it with target words more often for pre-lexical infants than advanced-lexical children, and to name target actions later into children’s development. Unlike American mothers, Indian mothers also abundantly used multimodal motherese to name target objects later into children’s development. Finally, monolingual mothers who spoke a verb-dominant Indian language used multimodal motherese more often than bilingual mothers who also spoke noun-dominant English to their child. The findings suggest that within a dynamic and reciprocal mother-infant communication system, multimodal motherese adapts to unify novel words and referents across cultures. It adapts to children’s level of lexical development and to ambient language-specific lexical-dominance hierarchies.

Studies of infant development concerned with the emergence of specific perceptual or cognitive abilities have typically focused on responsiveness in only one sensory modality. Research on infant perception, learning, and memory often attempts to reduce multimodal stimulation to "noise" and to control or omit stimulation from other sensory modalities in experimental designs. This type of unimodal research, although important, may not generalize well to the behavior of infants in the multimodal context of the everyday world. Research from animal and human development is reviewed that documents that significant differences in infants' perceptual skills and abilities can be observed under conditions of unimodal versus multimodal stimulation. These studies provide converging evidence for a functional distinction between unimodal and multimodal stimulation during early development and suggest that ecological validity can be enhanced when research findings are generalized appropriately to the natural environment and are not overgeneralized across stimulus properties, tasks, or contexts.

Seven-month-old infants require redundant information, such as temporal synchrony, to learn arbitrary syllable-object relations (Gogate & Bahrick, 1998). Infants learned the relations between 2 spoken syllables, /a/ and /i/, and 2 moving objects only when temporal synchrony was present during habituation. This article presents 2 experiments to address infants' memory for these relations. In Experiment 1, infants remembered the syllable-object relations after 10 min, only when temporal synchrony between the vocalizations and moving objects was provided during learning. In Experiment 2, 7-month-olds were habituated to the same syllable-object pairs in the presence of temporal synchrony and tested for memory after 4 days. Once again, infants learned and showed emerging memory for the syllable-object relations 4 days after original learning under the temporally synchronous condition. These findings are consistent with the view that prior to symbolic development, infants learn and remember word-object relation...

How do infants begin to understand spoken words? Recent research suggests that word comprehension develops from the early detection of intersensory relations between conventionally paired auditory speech patterns (words) and visible objects or actions. More importantly, in keeping with dynamic systems principles, the findings suggest that word comprehension develops from a dynamic and complementary relationship between the organism (the infant) and the environment (language addressed to the infant). In addition, parallel findings from speech and non-speech studies of intersensory perception provide evidence for domain general processes in the development of word comprehension. These research findings contrast with the view that a lexical acquisition device with specific lexical principles and innate constraints is required for early word comprehension. Furthermore, they suggest that learning of word–object relations is not merely an associative process. The data support an alternative view of the developmental process that emphasizes the dynamic and reciprocal interactions between general intersensory perception, selective attention and learning in infants, and the specific characteristics of maternal communication.