Validity in Phallometric Testing for Sexual Interests in Children: A Meta-Analytic Review

Abstract

Valid assessment of pedohebephilic interests (i.e., sexual interest in children) is fundamental to forensic clinical practice. Phallometric testing-which measures changes in penile circumference or volume, while stimuli depicting different ages and sexual activities are presented-is widely used in clinical and research settings to detect such interests. This meta-analysis summarizes studies comparing sexual offenders against children and various types of controls on phallometric tests for pedohebephilic interests (37 samples; N = 6,785) and studies examining the relationship between phallometric test scores and sexual reoffending (16 samples; N = 2,709). The findings suggest that several phallometric testing procedures are valid indicators of pedohebephilic interest. Certain methodological features of phallometric tests were associated with greater validity, such as, slide or audio-plus-slide stimuli and z-score-based indices. In addition, phallometric tests for pedohebephilic, pedophilic, and hebephilic interests predicted sexual reoffending which provides further evidence that phallometric test scores are valid indicators of sexual interest in children. In general, the interpretation of phallometric test scores as indicators of pedohebephilic interests is supported.

Are There Any Biomarkers for Pedophilia and Sexual Child Abuse? A Review

“…A current large meta-analysis (N = 6,785 subjects) suggests that several phallometric testing procedures are valid indicators of pedohebephilic interest (i.e., prepubescent and pubescent children) with small to large effect sizes. Moreover, phallometric tests were able to predict sexual reoffending with moderate effect sizes (N = 2,709 subjects) (108). A recent large study (N = 1,136) showed that most sex offenders against children (83%) were unable to successfully suppress their sexual arousal to pictures depicting children when instructed to do so.…”

Non-offending Pedophiles

“…Because sexual arousal to children is another strong predictor of engaging in sexual behavior with children in adjudicated sexual offenders [48,49], providing cognitive and behavioral techniques for managing sexual arousal may improve non-offending pedophiles' ability to manage sexual urges in their daily lives. This treatment focus is supported by recent research that finds self-reported pedohebephilic sexual interests are associated with markers of sexual preoccupation, such as higher rates of masturbation and higher frequency of sexual fantasies [23,24].…”

Use of penile plethysmography in the court: A review of practices in Canada, the United Kingdom and the United States

“…For the first and second criteria, the PPG has been the subject of numerous studies that have been published in peer‐reviewed journals. Although there is a long history of research on the PPG, within the last 5 years specifically, it has been studied using samples of men with pedophilic interests (Müller et al, ), examining attempts to dissimulate (Babchishin, Curry, Fedoroff, Bradford, & Seto, ; Trottier, Rouleau, Renaud, & Goyette, ), comparisons of PPG laboratories, techniques, and standardization (Demidova et al, ; Murphy & Fedoroff, ; Murphy, Ranger, Stewart, et al, , Murphy, Ranger, Fedoroff, et al, ), PPG stimuli (Dennis, Rouleau, Renaud, Nolet, & Saumur, ; Murphy et al, ; Murphy, Ranger, Fedoroff, Burke, & Dwyer, ; Rosetti et al, ), and meta‐analytic techniques (McPhail et al, ).…”

“…Regarding the error rate of the PPG, previous research has demonstrated that the PPG can accurately discriminate between men convicted of sex offenses against children from those who have not (e.g., Barbaree & Marshall, 1989;Freund & Blanchard, 1989;Lalumiere & Quinsey, 1994;McPhail et al, 2019). No test is without its limitations; however, widely accepted medical tests (e.g., hematologic blood values, endocrinologic hormone levels, blood pressure measurements, HIV screening tests) develop cut scores that balance specificity and sensitivity (e.g., Tan et al, 2016;Waaler, 1980).…”

“…Several published reports discuss the reliability and validity of PPG assessments (Fernandez, ; Marshall, ; McPhail et al, ; Merdian & Jones, ; Murphy et al, ). Concerning the utility of PPG, Marshall (), notes that, “Despite these reservations, phallometry remains the best approach to establishing a sex offender's sexual interest and, so long as the resultant data is interpreted [by experts and] with caution, they can usefully contribute to risk assessment and to defining targets for treatment” (p. 3).…”