Papers by Lorraine E. Bahrick
Principles of a dynamic, dyadic systems view of mother–infant face-to-face communication, which c... more 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. The process of interaction across time in a large low-risk community sample at infant age 4 months was examined. 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: (a) Significant moment-to-moment predictability within each partner (self-contingency) and between the partners (interactive contingency) characterizes mother–infant communication. (b) Interactive contingency is organized by a bidirectional, but asymmetrical, process: Maternal contingent coordination with infant is higher than infant contingent coordination with mother. (c) Self-contingency organizes communication to a far greater extent than interactive contingency. (d) 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 interrelated self-organizing processes.
This research examined the effects of bimodal audiovisual and unimodal visual stimulation on infa... more 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.
We explored the amount and timing of temporal synchrony necessary to facilitate prenatal perceptu... more 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 bob-white 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.
The world of objects and events floods our senses with continuously changing multimodal stimulati... more The world of objects and events floods our senses with continuously changing multimodal stimulation, but we can attend to only a small portion of this stimulation at any time.
In the simplest of terms, attention refers to a selectivity of response. Man or animal is continu... more In the simplest of terms, attention refers to a selectivity of response. Man or animal is continuously responding to some events in the environment and not to others that could be responded to (or noticed) just as well.
Research has demonstrated that infants recognize emotional expressions of adults in the first hal... more 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.
Although research has demonstrated impressive face perception skills of young infants, little att... more 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.
Research with human infants as well as non-human animal embryos and infants has consistently demo... more Research with human infants as well as non-human animal embryos and infants has consistently demonstrated the benefits of intersensory redundancy for perceptual learning and memory for redundantly specified information during early development. Studies of infant affect discrimination, face discrimination, numerical discrimination, sequence detection, abstract rule learning, and word comprehension and segmentation have all shown that intersensory redundancy promotes earlier detection of these properties when compared to unimodal exposure to the same properties. Here we explore the idea that such intersensory facilitation is evident across the life-span and that this continuity is an example of a developmental behavioral homology. We present evidence that intersensory facilitation is most apparent during early phases of learning for a variety of tasks, regardless of developmental level, including domains that are novel or tasks that require discrimination of fine detail or speeded responses. Under these conditions, infants, children, and adults all show intersensory facilitation, suggesting a developmental homology. We discuss the challenge and propose strategies for establishing appropriate guidelines for identifying developmental behavioral homologies. We conclude that evaluating the extent to which continuities observed across development are homologous can contribute to a better understanding of the processes of development. ß
Two experiments assessing event-related potentials in 5-month-old infants were conducted to exami... more 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.
Selective attention is the gateway to perceptual processing, learning, and memory and is a skill ... more 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... more 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.
This study investigated 7-month-old infants' ability to relate vowel sounds with objects when int... more This study investigated 7-month-old infants' ability to relate vowel sounds with objects when intersensory redundancy was present versus absent. Infants (N = 48) were habituated to two alternating video-films of vowel-object pairs in one of three conditions. In the moving-synchronous condition, where redundancy was present, the movement of one object was temporally coordinated with the spoken vowel Ial and that of the other with Ii!, simulating showing and naming the objects to the infant. In the still and in the movingasynchronous conditions, where redundancy was absent, infants saw static objects, and objects moving out of synchrony with the vowel sounds, respectively. The results indicated that infants detected a mismatch in the vowel-object pairs in the movingsynchronous condition but not in the still or the moving-asynchronous condition. These findings demonstrate that temporal synchrony between vocalizations and the motions of an object facilitates learning of arbitrary speech-object relations, an important precursor to the development of lexical comprehension in infancy.
This study assessed an intersensory redundancy hypothesis, which holds that in early infancy info... more This study assessed an intersensory redundancy hypothesis, which holds that in early infancy information presented redundantly and in temporal synchrony across two sense modalities selectively recruits attention and facilitates perceptual differentiation more effectively than does the same information presented unimodally. Five-month-old infants' sensitivity to the amodal property of rhythm was examined in 3 experiments. Results revealed that habituation to a bimodal (auditory and visual) rhythm resulted in discrimination of a novel rhythm, whereas habituation to the same rhythm presented unimodally (auditory or visual) resulted in no evidence of discrimination. Also, temporal synchrony between the bimodal auditory and visual information was necessary for rhythm discrimination. These findings support an intersensory redundancy hypothesis and provide further evidence for the importance of redundancy for guiding and constraining early perceptual learning.
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Papers by Lorraine E. Bahrick