CROSS-MODAL FACILITATION OF INFANT VISUAL FIXATION - TEMPORAL AND INTENSITY EFFECTS

Cross-modal facilitation of infants' visual fixation by simple auditory stimuli was studied in five experiments. In Experiment 1, decremented fixation of a repeatedly presented black-and-white check pattern was dishabituated by the concurrent presentation of a 1000-Hz, 75-dB tone. The tone also increased looking when compounded with a uniformly illuminated (blank) visual field. Furthermore, facilitation persisted on the trial following the tone-pattern compound, when either the familiarized pattern was retested (Experiments 1 and 2) or a novel pattern was introduced (Experiment 3). Dishabituation (Experiment 2) and enhanced responses to a novel stimulus (Experiment 3) were eliminated by increasing from 10 to 30 s the delay between the termination of the tone-pattern compound and the onset of the pattern-alone trial. In Experiment 4, the magnitude of cross-modal dishabituation was shown to increase as tone intensity increased between 55 and 75 dB. In Experiment 5, dishabituation occurred when a 1000-Hz, 84-dB tone was added, or when pattern check density was shifted upward, and an additive effect was obtained when the two changes were combined. These findings are generally consistent with the view that some auditory stimuli engage a general state-dependent arousal process. Alternative explanations of cross-modal facilitation are considered. © 1991.