Effects of multimodal synchrony on infant attention and heart rate during events with social and nonsocial stimuli.

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.

Measuring Sustained Attention and Perceived Workload.

OBJECTIVE: We examined the effects of spatial uncertainty, field dependence/independence (FD/I), and sex on vigilance performance and perceived workload in elementary school children. BACKGROUND: Building on previous work in which children demonstrated their ability to evaluate workload, we tested whether spatial-uncertainty manipulations in a vigilance task would elicit in children the same deleterious effects on performance and workload as it does with adults. We also examined individual difference effects associated with FD/I and sex to determine their influence on both performance and workload. METHOD: In the low-uncertainty task, stimuli appeared in the center of the computer screen; in the high-uncertainty task, they appeared in one of the four quadrants of the screen. Neutral events consisted of uppercase letter strings. Critical signals consisted of a single lowercase letter among uppercase letters. Following each vigil, children completed a workload assessment via a modified version of the NASA Task Load Index. RESULTS: Children showed lower perceptual sensitivity, greater response latency variability (RTSD), and a higher response criterion in the uncertain display condition. Workload scores reflected these performance differences. Field-dependent children showed lower perceptual sensitivity and greater RTSD than did field-independent children. The two groups exhibited differing workload profiles. Despite no objective performance differences, boys reported greater workload than girls. CONCLUSION: The scale demonstrated sensitivity and diagnosticity with regard to both the task variable and individual differences. APPLICATION: These findings contribute to the emerging field of "educational ergonomics" and indicate that appropriate assessment tools might identify children who are experiencing increased workload.

The role of event rate, temporal expectancy, and sensory modality in continuous performance of children and adults.

This study explored developmental differences in the effects of event rate, temporal expectancy, and sensory modality on continuous performance. Children (ages 7-8 years) and college-aged adults completed visual and auditory continuous performance tasks (CPTs) that were equated at an intermediate (20 events/min) rate using the perceptual sensitivity index (d') and then were compared at faster (40 events/min) and slower (10 events/min) rates to determine the influence of event rate on continuous performance of children and adults. To investigate the effects of temporal expectancy, 20% of the critical signals and neutral events occurred early or late relative to the regular rhythm of the task. The findings (a) suggest that event rate influences continuous performance differently for children and adults, (b) highlight the role of temporal expectancy in continuous performance, and (c) reveal differences in the effects of event rate and temporal expectancy on visual and auditory continuous performance.

Equating tasks and sustaining attention in children and adults: the methodological and theoretical utility of d' matching.

The present study develops a method to create task equivalency for children and adults in vigilance research. Experiment 1 employed the signal detection index of perceptual sensitivity (d') to calibrate vigilance tasks for 32 children (ages 7-8) and 32 adults. The results of Experiment 1 suggest that task equivalency across groups can be attained, and a vigilance decrement was observed for children. In Experiment 2, the task parameter of event rate was manipulated across two vigils. Again, 32 children (ages 7-8) and 32 adults participated. The results suggest that a reverse event rate effect emerged for both children and adults. In addition, developmental differences in response to the event rate manipulation and with respect to the vigilance decrement emerged: Children benefited less from the manipulation and were more likely to demonstrate a vigilance decrement than were adults. No developmental differences emerged for the sensitivity decrement. The results are explained with reference to how task demands interact with participant arousal, and implications for development and for future research are discussed.