The phallometric assessment of sex offenders: some professional and research issues

Abstract

Phallometry (or penile plethysmography) is a technique for measuring penile erection in response to a variety of stimuli, used with many procedural varia~ tions in different sex offender assessment centres . Recent research suggests that penile plethysmography, in spite of its many unresolved methodological problems, is both valid and reliable. The technique is ideaUy suited to challenge sex offenders' denials, assess their treatment needs and to evaluate treatment, although it can not be relied upon, on its own, to establish guilt or predict future deviant sexual behav~ iour. An examination of current practice suggests a number of areas where research is needed: to design and standardise stimulus material; to provide more reliability data; to develop and test procedures to discourage faking; and to carry out validation studies with forensic and non~forensic populations (which include a detailed analysis of the subjects' sexual history, motivation and fantasies). Finally, professional guide~ lines are needed to control conduction and interpretation of assessments, use of stim~ uli and counselling of clients.

The probabilities of sex offender re‐arrest

“…8. The unreliability of phallometric discrimination of sexual preference (once a key theoretical construct) in the assessment of treatment outcomes has now also been acknowledged (Castonguay et al, 1993;Lanauy 1994;Proulx et al, 1994;Marshall, 1996).…”

The phallometric assessment of sex offenders: an update

“…More recent studies, such as those conducted by Professor Henry E. Adams of the University of Georgia in the USA for instance, clearly demonstrate the efficacy of the technique at identifying men's gender sexual interests. One study , designed to assess the extent to which homosexual and heterosexual men can suppress their sexual response, verified the common finding that suppressing one's sexual response is easier than enhancing it (similar earlier findings were reviewed in Launay, 1994) but also showed excellent discrimination between the two groups when subjects were instructed to respond normally. In another study, Adams et al (1996) tested two groups, both of them heterosexual but one with strong homophobic views.…”

“…Seven English prisons (Albany, Brixton, Dartmoor, Full Sutton, Maidstone, Wandsworth and Whitemoor) have been fully equipped and staff trained during 1998. The stimuli consist of a reduced version of the MAR, a series of two-minute videoclips depicting consenting sex, rape and non-sexual violence against women, as described elsewhere (Launay, 1994), and still pictures of children and adults (computer composite) grouped in threes, so that three pictures of naked pre-pubescent boys may be followed by three pictures of pre-pubescent girls etc. ; this is following evidence from Hart and Willmott (1994), who demonstrated that presenting pictures in groups was more discriminatory than presenting them singly.…”

“…(Marshall, 1996, p. 168) What are clinicians to make of this confusion and what weight should they give to the results of a phallometric assessment? The objective of this paper is to assess the progress in the field of penile plethymography since the author's last review (Launay, 1994) and use these findings together with the author's experience of the Maidstone prison laboratory to guide practitioners.…”

Relapse prevention with sex offenders: practice, theory and research

“…Yates et al (1984) (described in Launay, 1994) showed that that subjects who had been made to feel angry towards a woman before an assessment of sexual interests produced higher erectile response to a rape scene. The reason why no attempt has been made to replicate such dramatic results is presumably that the design is ethically difficult to justify.…”