Evoked Response Correlates of Meaningful Visual Stimuli in Children

ABSTRACT Photographic slides of familiar objects or cartoons were tachistoscopically presented to a group of 79 normal children (age 5‐11 years) in a study of the evoked response correlates of meaningful visual stimuli. Control stimuli consisted of blank slides or defocused cartoons matched for brightness. A warning flash preceded the slides by 1 sec. EEG and eye movement potentials were recorded on line with a 9.5 sec time constant and averaged off‐line. The principal finding was a vertex negative slow potential peaking about 500 msec after slide presentation which correlated with reports of interest in and recall of both objects and cartoons. Responses in the occipital region changed less consistently with pictorial material, and were the same to the warning flash whether it preceded control or test stimuli. The vertex negative response appears to be a corollary of perceptual integration of meaningful stimuli. Among alternative explanations nonspecific differences in arousal level and/or expectancy appear to be unlikely on the basis of our data. A primary role of edge contrast in generating these late negative responses would not be predicted on the basis of published evidence, but our attempt to control for this alternative yielded equivocal results.