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Biomedical subjects

L E Bahrick

Publications and source records attributed to L E Bahrick.

13 recordsLinked to original sources
PubMed2001

Increasing specificity in perceptual development: infants' detection of nested levels of multimodal stimulation.

This research assessed the development of infants' sensitivity to two nested amodal temporal relations in audible and visible events. Their detection of global temporal synchrony between visible and audible impacts and internal temporal structure nested within each impact specifying object composition (single versus compound objects) was assessed. Infants of 4, 7, and 11 weeks of age were habituated to a single and a compound object striking a surface and then received test trials depicting a change in synchrony or object composition. Results indicated an interaction between age and condition where sensitivity to synchrony was present by 4 weeks and remained stable across age, whereas sensitivity to composition emerged later, by 7 weeks, and increased dramatically with age. These findings converge with other recent findings to illustrate a pattern of increasing specificity in the development of perception, where infants first detect global and later detect embedded relations. The early sensitivity to global relations may provide an organizational framework for development by focusing infant attention on unitary events, guiding and constraining further exploration, and buffering infants from learning incongruent relations.

Auditory Perception↗
PubMed2000

Intersensory redundancy guides attentional selectivity and perceptual learning in infancy.

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.

Attention↗
PubMed2000

The development of infant intersensory perception: advantages of a comparative convergent-operations approach.

Despite impressive demonstrations of human infants' intersensory capabilities over the past several decades, there has been little focus on the contributions of prenatal and postnatal experience or the specific developmental processes underlying the emergence of intersensory functioning. Research with nonhuman animals has, however, provided a number of advances in understanding early intersensory perception. The authors explore the value of a comparative, convergent-operations approach to the study of early intersensory perception and examine how this approach has highlighted the study of (a) prenatal factors, (b) brain-behavior relations, and (c) context and experience variables contributing to infants' intersensory responsiveness. Examples of how human and animal research programs can cross-fertilize one another in their attempts to understand developmental processes underlying intersensory perception are considered.

Animals↗
PubMed1998

Intersensory redundancy facilitates learning of arbitrary relations between vowel sounds and objects in seven-month-old infants.

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 /a/ and that of the other with /i/, simulating showing and naming the objects to the infant. In the still and in the moving-asynchronous 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 moving-synchronous 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.

Attention↗
PubMed1998

Intermodal perception of adult and child faces and voices by infants.

This research investigated the ability of 4- and 7-month-old infants to match unfamiliar, dynamic faces and voices on the basis of age or maturity. In Experiment 1, infants received videotaped trials of an adult and a child of the same gender, side by side, speaking a nursery rhyme in synchrony with one another. The voice to one and then the other face was played in synchrony with the movements of both faces in a random order across 12 trials. On one block of 6 trials a man and a boy were presented, and on the other block a woman and a girl. Results indicated significant matching of the faces and voices at both ages, and the infant's prior experience with children appeared to facilitate matching at 7 months. Further, a visual preference for the children's faces was found. Experiment 2 assessed matching to the same events by 7-month-olds, only with the faces inverted. Results indicated no evidence of matching; however, the visual preference for the children's faces was replicated. Together, the findings suggest that infants are able to detect invariant intermodal relations specifying the age or maturity of a person's face and voice. This matching was most likely based on information that was degraded by inverting the faces, including invariant relations between the sound of the voice and configurational aspects of the face, or between temporal aspects of the voice and the relative motion of facial features.

Adult↗
PubMed1997

The effect of retrieval cues on visual preferences and memory in infancy: evidence for a four-phase attention function.

Bahrick and Pickens (1995) proposed a four-phase model of infant attention, suggesting that recent memories are expressed as a visual preference for novelty, intermediate memories as a null preference, and remote memories as a preference for familiarity. The present study tested a hypothesis generated from this model that a retrieval cue would increase memory accessibility and shift visual preferences toward greater novelty to resemble more recent memories. Results confirmed our predictions. After retention intervals associated with remote memory, previously observed familiarity preferences shifted to null preferences, whereas after a retention interval associated with intermediate memory, the previously observed null preference shifted to a novelty preference. Further, a second experiment found that increasing the exposure to the retrieval cue could shift the familiarity preference to a novelty preference. These findings support the four-phase model of infant attention and suggest that novelty, null, and familiarity preferences lie along a continuum and shift as a function of memory accessibility.

Attention↗
PubMed1995

Infant memory for object motion across a period of three months: implications for a four-phase attention function.

Memory for object motion in 3-month-old infants was investigated across retention intervals of 1 or 3 months in three studies using a novelty preference method. Following familiarization to an object undergoing one of two types of motion, visual preferences for the novel motion were assessed after retention intervals of 1 min, 1 day, and 1 month (Experiment 1, N = 120) and 1 min, 1 day, 2 weeks, and 1 month (Experiment 2, N = 74). Results of both studies indicated a significant preference for the novel motion at the 1-min delay, a significant preference for the familiar motion at the 1-month delay, and no preferences at the intermediate retention intervals. In Experiment 3, memory was assessed after a 3-month interval and again, a significant familiarity preference was obtained. These results demonstrate that memory for object motion lasts across retention intervals of 1 and 3 months and that novelty and familiarity preferences interact with retention time. A four-phase function relating visual preferences and retention time was proposed. Phase 1, recent memory, is characterized by a novelty preference; phase 2, intermediate memory, is a period of transition characterized by no visual preference; phase 3, remote memory, is characterized by a familiarity preference; and phase 4, inaccessible memory, is also characterized by no preference. The finding of a transition period at intermediate retention times suggests that null preferences should not necessarily be taken as evidence of forgetting. Rather, more extended retention intervals should be included to interpret null findings obtained in the novelty preference method.

Attention↗
PubMed1994

Fifty years of language maintenance and language dominance in bilingual Hispanic immigrants.

Spanish language tests of 801 Cuban and Mexican immigrants showed no evidence of language loss during 50 years of U.S. residence; a few years after immigration, their English vocabulary approximated that of English monolinguals. The critical-age hypothesis was not supported for the acquisition of English vocabulary when English schooling and language usage were controlled by multiple regression. Most Ss continued to speak about as much Spanish as English; but read, wrote, and heard (on television and radio) far more English than Spanish. Under these conditions, Ss maintained Spanish dominance on tests of vocabulary recognition, lexical decision, and oral comprehension. Dominance was task specific and shifted to English on a category generation task about 12 years after immigration. No evidence of bilingual language interference was found; this is attributed to the strong Spanish foundation of the participants.

Adult↗
PubMed1992

Infants' perceptual differentiation of amodal and modality-specific audio-visual relations.

Ninety-six infants of 3 1/2 months were tested in an infant-control habituation procedure to determine whether they could detect three types of audio-visual relations in the same events. The events portrayed two amodal invariant relations, temporal synchrony and temporal microstructure specifying the composition of the objects, and one modality-specific relation, that between the pitch of the sound and the color/shape of the objects. Subjects were habituated to two events accompanied by their natural, synchronous, and appropriate sounds and then received test trials in which the relation between the visual and the acoustic information was changed. Consistent with Gibson's increasing specificity hypothesis, it was expected that infants would differentiate amodal invariant relations prior to detecting arbitrary, modality-specific relations. Results were consistent with this prediction, demonstrating significant visual recovery to a change in temporal synchrony and temporal microstructure, but not to a change in the pitch-color/shape relations. Two subsequent discrimination studies demonstrated that infants' failure to detect the changes in pitch-color/shape relations could not be attributed to an inability to discriminate the pitch or the color/shape changes used in Experiment 1. Infants showed robust discrimination of the contrasts used.

Acoustic Stimulation↗
PubMed1988

Intermodal learning in infancy: learning on the basis of two kinds of invariant relations in audible and visible events.

In this research, the development of intermodal perception in infancy was examined by using a new method, the intermodal learning method. 3-month-old infants were given the opportunity to learn a relation between 2 single film and soundtrack pairs through a 2-min familiarization period under 1 of 4 conditions. Films of naturalistic events were accompanied by a soundtrack that was (1) appropriate to the composition of the object and synchronous with its motions, (2) appropriate and nonsynchronous, (3) inappropriate and synchronous, or (4) inappropriate and nonsynchronous. A group of control subjects was familiarized with irrelevant films and soundtracks. Then all subjects were tested in a 2-choice intermodal preference test to determine under which familiarization conditions intermodal learning had occurred. Results indicated that only subjects who had been familiarized with appropriate and synchronous film and soundtrack pairs showed evidence of intermodal learning as compared with the performance of control subjects. Intermodal learning occurred on the basis of 2 kinds of invariant audio-visual relations, temporal synchrony, and temporal microstructure specifying the composition of the object. Intermodal learning did not occur through association on the basis of co-occurrence, nor did it occur when any incongruent audio-visual structure was present. These findings support an invariant-detection view of the development of intermodal perception.

Association Learning↗
PubMed1980

Detection of elasticity as an invariant property of objects by young infants.

Three-month-old infants were habituated to two different motions of deformation, presented 'live' with an object of sponge rubber. After habituation, one-third of the subjects was presented with a third deforming motion; one-third was presented with a rigid motion of the same object; and the other third was presented with a continuation of the habituation sequence. The group presented with a rigid motion dishabituated, exhibiting a sharp increase in looking time. The other two groups showed little or no increase. These results suggest that infants perceive elasticity of substance, in contrast to rigidity, as an invariant property of an object over different deforming motions.

Elasticity↗
PubMedDate not supplied

A study of multimodal motherese: the role of temporal synchrony between verbal labels and gestures.

This study examined European American and Hispanic American mothers' multimodal communication to their infants (N = 24). The infants were from three age groups representing three levels of lexical-mapping development: prelexical (5 to 8 months), early-lexical (9 to 17 months), and advanced-lexical (21 to 30 months). Mothers taught their infants four target (novel) words by using distinct objects during a semistructured play episode. Recent research suggests that young infants rely on temporal synchrony to learn syllable-object relations, but later, the role of synchrony diminishes. Thus, mothers' target and nontarget naming were coded for synchrony and other communication styles. The results indicated that mothers used target words more often than nontarget words in synchrony with object motion and sometimes touch. Thus, "multimodal motherese" likely highlights target word-referent relations for infants. Further, mothers tailored their communication to infants' level of lexical-mapping development. Mothers of prelexical infants used target words in synchrony with object motion more often than mothers of early- and advanced-lexical infants. Mothers' decreasing use of synchrony across age parallels infants' decreasing reliance on synchrony, suggesting a dynamical and reciprocal environment-organismic relation.

Adult↗