Preventing faking in phallometric assessments of sexual preference.

This study evaluated a method of preventing sexual preference faking in phallometric assessments employing audiotaped stimuli. The stimuli were stories describing neutral heterosocial interactions, consenting heterosexual activity, rape, and nonsexual violence. Sixteen normal heterosexual males were each tested with ordinary instructions, with fake instructions (i.e., to appear sexually interested in rape and nonsexual violence but not in consenting sex), and with fake instructions while performing a secondary semantic tracking task. The tracking task was to press one button whenever sexual activity was being described and another button whenever violence occurred. This simple task was designed to focus subjects' attention on only the critical elements of the stories. Group data indicated that subjects could fake inappropriate preferences when instructed to do so without the semantic tracking task but could not when the task was required. The implications of these findings for ethical practice and for the theoretical interpretation of phallometric assessment data were discussed.