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

Abstract

Penile plethysmography (PPG) is an objective measure of male sexual arousal in response to the presentation of a series of erotic and neutral stimuli. This measure is now widely recognized as the most reliable means of objectively measuring male sexual arousal to specific stimuli. Many clinicians and researchers consider PPG to be a vital contribution to the assessment and treatment of adult men with paraphilic interests and men who have committed sex crimes. PPG contributes to the clinical assessment of paraphilic interests, appraisal of risk of recidivism, and provides an objective measurement of changes in sexual arousal in response to treatment. There is strong support for the utility of PPG within clinical and legal contexts. This article addresses ways in which PPG has been utilized in the courts as part of expert clinical opinion. History of its use, details regarding admissibility in court, and case law are explored within the legal systems of Canada, the UK and the USA. Support for the inclusion of PPG as expert evidence is provided and judicial misunderstandings on the rationale for PPG use and its clinical utility in forensic assessments are discussed.

International overview of phallometric testing for sexual offending behaviour and sexual risk

“…Phallometry response profiles should only be interpreted by experts (often forensic psychiatrists and psychologists with specific training), and the results should be used only as a supplementary resource to guide clinical impressions. 3 Ethically, investigation should focus upon PSIs relevant to the presenting issue. Established sexual behaviour clinics, such as those in Canada and the USA, incorporate phallometry into comprehensive clinical evaluations alongside review of objective information, such as criminal records.…”

“…For example, phallometric evidence is submitted to criminal sentencing in Canada more commonly than in the USA or the UK. 3 However, in none of these countries is phallometric evidence used to determine guilt. Phallometry is also incorporated into quasi-judicial decisions about release from custody or discharge from secure hospitals.…”

“…Phallometry is also incorporated into quasi-judicial decisions about release from custody or discharge from secure hospitals. 3 A minority of sexual offences (e.g. 5% in North America) are committed by women, and some research has objectively measured sexual arousal in female PCSOs, although this work is relatively underdeveloped.…”

“…Such concerns resulted in phallometry being banned in UK prisons in the 1980s, for example, although this was reversed a few years later when evidence-based treatment programmes for sex offenders were introduced. 3 Moreover, there are ethical concerns about examinees being coerced into testing when a court orders it. Proponents argue that only the meeting with the psychiatrists is mandated and phallometry is done with informed consent (e.g.…”

“…Phallometry may be important to the management of PCSOs because specific sexual response profiles predict recidivism 3 and phallometric tests are valid indicators of paedophilic interests, both for PCSOs against children and controls. 6 Thus, it is incorporated into the evaluation of PSIs, into risk assessment and into measuring response to sex offender treatment.…”