Pupillary Response as an Age-Specific Measure of Sexual Interest

Abstract

In the visual processing of sexual content, pupil dilation is an indicator of arousal that has been linked to observers' sexual orientation. This study investigated whether this measure can be extended to determine age-specific sexual interest. In two experiments, the pupillary responses of heterosexual adults to images of males and females of different ages were related to self-reported sexual interest, sexual appeal to the stimuli, and a child molestation proclivity scale. In both experiments, the pupils of male observers dilated to photographs of women but not men, children, or neutral stimuli. These pupillary responses corresponded with observer's self-reported sexual interests and their sexual appeal ratings of the stimuli. Female observers showed pupil dilation to photographs of men and women but not children. In women, pupillary responses also correlated poorly with sexual appeal ratings of the stimuli. These experiments provide initial evidence that eye-tracking could be used as a measure of sex-specific interest in male observers, and as an age-specific index in male and female observers.

Keywords: Eye-tracking; Pupillary response; Sexual appeal; Sexual interest.

Fig. 1

The stimuli of the original quality condition in Experiment 1

Fig. 2

Example stimuli of the original quality, high quality, and the luminance-controlled image conditions in Experiment 1 and the scrambled images in Experiment 2

Fig. 3

Mean percentage fixations to the head and body of the target persons and the scene background for male and female observers in Experiment 1. Lines represent standard errors of the means

Fig. 4

Percentage pupillary change for all stimulus categories for male and female observers in Experiment 1. Lines represent standard errors of the means

Fig. 5

Percentage pupillary change for all stimulus categories for male and female observers in Experiment 2 for intact scenes (left graph) and scrambled scenes (right graph). Lines represent standard errors of the means