Dissimulation in phallometric testing of rapists' sexual preferences

Area of Science:

• Forensic Psychology
• Sex Offender Assessment

Background:

• Assessing sexual preferences in sex offenders is crucial for treatment and risk management.
• Phallometry is a common tool, but its discriminant validity can be limited.

Purpose of the Study:

• To evaluate the effectiveness of a semantic tracking task in enhancing phallometric assessment of sexual preferences.
• To determine if this task improves the ability to differentiate rapists from non-sex offenders.

Main Methods:

• Thirty-eight incarcerated rapists underwent phallometric assessment with and without a concurrent semantic tracking task.
• Participants listened to vignettes depicting neutral, consensual sexual, rape, and nonsexual violent content.
• The semantic task required participants to differentiate between violent and sexual content.

Main Results:

• Phallometric assessment combined with the semantic task showed significantly better discrimination between rapists and non-sex offenders compared to assessment without the task.
• Among rapists with prior phallometric experience, a strong correlation was found between sexual deviance scores and tracking accuracy.

Conclusions:

• The semantic tracking task enhances the discriminant validity of phallometric assessments for sexual preferences.
• This modified approach may be particularly beneficial for assessing sex offenders with previous exposure to phallometric testing.