Lorraine E. Bahrick

Detection of Intermodal Proprioceptive-Visual Contingency as a Potential Basis of Self-Perception in Infancy.

Five-month-old infants can detect the invariant relationship between their own leg motion and a video display of that motion. In three experiments they discriminated between a perfectly contingent live display of their own leg motion and a noncontingent display of self or a peer. They showed this discrimination by preferential fixation of the noncontingent display. This effect was evident even when the infants direct view of his or her own body was occluded, eliminating video image discrimination on the basis of an intramodal visual comparison between the sight of selfmotion and the video display of that motion. These findings suggest hat the contingency provided by a live display of ones body motion is perceived by detecting the invariant intermodal relationship between proprioceptive information for motion and the visual display of that motion. The detection of these relations may be fundamental to the development of self-perception in infancy. In addition, though 3month-olds did not show significant discrimination of the contingent and noncontingent displays, they did show significantly more extreme looking proportions to the two displays than did the 5-month-olds. This may reflect the infants progression from self to social orientation.

Intersensory Redundancy Guides the Development of Selective Attention, Perception, and Cognition in Infancy

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.

Maintenance of Foreign Language Vocabulary and the Spacing Effect

In a 9-year longitudinal investigation, 4 subjects learned and relearned 300 English-foreign language word pairs. Either 13 or 26 relearning sessions were administered at intervals of 14, 28, or 56 days. Retention was tested for 1.2.3. or 5 years after training terminated. The longer intersession intervals slowed down acquisition slightly, but this disadvantage during training was offset by substantially higher retention. Thirteen retraining sessions spaced at 56 days yielded retention comparable to 26 sessions spaced at 14 days. The retention benefit due to additional sessions was independent of the benefit due to spacing, and both variables facilitated retention of words regardless of difficulty level and of the consistency of retrieval during training. The benefits of spaced retrieval practice to long-term maintenance of access to academic knowledge areas are discussed.

Weathering the storm: Children's long‐term recall of Hurricane Andrew

Children who experienced a highly stressful natural disaster, Hurricane Andrew, were interviewed within a few months of the event, when they were 3–4 years old, and again 6 years later, when they were 9–10 years old. Children were grouped into low, moderate, or high stress groups depending on the severity of the experienced storm. All children were able to recall this event in vivid detail 6 years later. In fact, children reported over twice as many propositions at the second interview as at the first. At the initial interview, children in the high stress group reported less information than children in the moderate stress group, but 6 years later, children in all three stress groups reported similar amounts of information. However children in the high stress group needed more questions and prompts than children in the other stress groups. Yet children in the high stress group also reported more consistent information between the two interviews, especially about the storm, than children in the other stress groups. Implications for childrens developing memory of stressful events are discussed.

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.

The effects of stress on young children's memory for a natural disaster

The effects of stress on childrens long-term memory for a major hurricane were studied. Stress was objectively defined as low, moderate, or high according to the severity of damage to the childs home. One hundred 3and 4-year-old children received a structured interview 2-6 months following the hurricane. Older children recalled and elaborated more than younger children. Prompted recall was greater than spontaneous recall. There was a quadratic function, consistent with an inverted U-shaped curve, relating storm severity with overall as well as spontaneous recall. These findings can be applied to the effects of stress on the amount recalled by children giving retrospective accounts of temporally extended, naturalistic events.

Infants' perception of substance and temporal synchrony in multimodal events

Four-month-old infants can detect a relationship between the soundtracks and films of rigid and elastic objects in motion. When movies of these two kinds of objects were shown side by side along with the soundtrack to one of them, infants predominately watched the sound films. Three subsequent studies explored the basis of this intermodal perception. It was found that infants detected bimodal temporal structure specifying object rigidity and elasticity, and temporal synchrony between the sights and sounds of object impact. These results support the view that the development of intermodal perception is based on the detection of invariant relations in visual and acoustic stimulation.

Attention and Memory for Faces and Actions in Infancy: The Salience of Actions over Faces in Dynamic Events

Discrimination and memory for video films of women performing different activities was investigated in 5.5 month-old infants. In Experiment 1, infants (N = 24) were familiarized to the faces of one of three women performing one of three repetitive activities (blowing bubbles, brushing hair, and brushing teeth). Overall, results indicated discrimination and memory for the actions but not the faces after both a 1-min and a 7-week delay. Memory was demonstrated by a visual preference for the novel actions after the 1-min delay and for the familiar actions after the 7-week delay, replicating prior findings that preferences shift as a function of retention time. Experiment 2 (N = 12) demonstrated discrimination and memory for the faces when infants were presented in static poses at the 1-min delay, but not the 7-week delay. In Experiment 3 (N = 18), discrimination of the actions was replicated, but no discrimination among the objects embedded in the actions (hairbrush, bubble wand, toothbrush) was found. These findings demonstrate the attentional salience of actions over faces in dynamic events to 5.5 month-olds. They highlight the disparity between results generated from moving versus static displays in infancy research and emphasize the importance of using dynamic events as a basis for generalizing about perception and memory for events in the real world.

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.

Infants' perception of rhythm and tempo in unimodal and multimodal stimulation: a developmental test of the intersensory redundancy hypothesis.

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.