A comparison of objective measures of sexual arousal and interest: visual reaction time and penile plethysmography.

This study assessed the reliability and validity of a visual reaction time (VRT) measure of sexual interest (G. G. Abel, J. Huffman, B. Warberg, & C. L. Holland, 1998) and the penile plethysmograph (PPG) with audio stimuli. A sample of 57 sex offenders incarcerated at a high-security military prison completed physiological and self-report measures of sexual interest, including the VRT and the PPG. Results indicated adequate internal consistency for both measures. Convergent validity and an assessment of clinical usefulness for both measures indicated that (a) both measures accurately identified offenders against young boys; (b) the VRT, but not the PPG, significantly identified offenders against adolescent girls; (c) neither measure reached statistical significance in identifying offenders against adult women; and (d) the VRT did not reach statistical significance in identifying offenders against young girls and the PPG did reach statistical significance but in the opposite direction as was expected (i.e., men with female child victims had significantly lower arousal to female child stimuli than did men in other victim choice categories).