Pupillary and Cardiac Activity During Visual Attention

ABSTRACT Thirty pictures, rated on 22 scales, were shown to 34 males, while pupillary diameters and heart rates were recorded, to test the prediction that attention to the environment leads to sympathetic‐like dilatation and parasympathetic‐like cardiac slowing, and to study the relationships of the responses to stimulus‐attributes. The prediction was satisfied, demonstrating directional fractionation and situational stereotypy. Tonic levels changed significantly during the experiment and also showed directional fractionation. A few individuals and stimuli, however, yielded reliable pupillary constriction, demonstrating intra‐stressor stereotypy. Four factors characterized the ratings, two of which were associated with the autonomic responses. Pupillary dilatation and cardiac slowing increased as the Attention‐Interest value increased. Pupillary dilatation was greatest to pictures midway on the Pleasantness‐Evaluation factor, and greater to unpleasant than to pleasant stimuli. Cardiac slowing was linearly related to pleasantness, with unpleasant stimuli provoking the greatest slowing. The two responses were correlated less than measurement reliability would have allowed, demonstrating quantitative dissociation. When base‐corrected scores were used the correlations again were low and highly variable among subjects and stimuli, even in direction.