De Jesus, L. M. (1984). Arousal in relation to the degree of realism in visual stimuli. Unpublished Ph.D., Indiana University.

The purpose of the present study was to examine the effects of degree of realism and type of content of visual stimuli upon levels of arousal. One independent variable, type of content, had three values: pleasant, neutral, and unpleasant. The other independent variable, degree of realism, had four values: color photograph, black-and-white photograph, photo-sketch, and free-hand sketch. The two independent variables were combined in a 3 x 4 factorial design with repeated measures for one variable: degree of realism. Separate analyses were done for each one of two dependent variables. The two dependent variables were galvanic skin response (GSR) and pupillary response (PR).

The subjects were 30 male paid volunteers, with an average age of 22, who did not wear glasses and were not color blind as measured by the Ishihara test. Subjects were presented a series of visual stimuli which varied according to degree of realism and type of content. Each subject saw 12 experimental slides (three slides for each one of the four degrees of realism) and 12 control slides (grey slides). Ten subjects saw the pleasant stimuli, ten subjects saw the neutral stimuli, and ten subjects saw the unpleasant stimuli. The GSR and PR were recorded for each subject.

The results of the analysis of variance and a studentized range test for GSR showed that for unpleasant stimuli color photographs were significantly more arousing than black-and-white photographs, photo-sketches, and free-hand sketches. There was not a significant difference between black-and-white photographs, photo-sketches, and free-hand sketches.

The results of the analysis of variance and studentized range test for PR showed that with greater realism, pleasant stimuli resulted generally in higher PR. However, free-hand sketches, the least realistic stimuli, resulted in significantly higher PR than did the next to least realistic stimuli, photo-sketches.

The results of the present study suggest that the additional time and cost required to produce pictorial material in color may sometimes be justified in communications that are designed to produce arousal in their audiences.