This study determined whether a particular picture set of clothed persons in five stages of sexual maturation from infancy to adulthood could be used in diagnosing pedophilia.
Since the use of picture stimuli for the assessment of pedophilic sexual interest is constrained by ethical and legal considerations, stimulus material for diagnosing pedophilia must be non-suggestive and non-pornographic. As a consequence, Laws and Gress (2004) developed a picture set that was standardized for levels of sexual maturity and contained only non-suggestive, modified pictures that did not show any natural persons. The resulting "Not-Real-People" (NRP) picture set consists of 160 images: eight pictures for each of five categories of sexual maturity in either sex with a clothed and a nude variant. The testing of the NRP picture set determined that the stimuli are suitable for diagnosing pedophilia. Participants' decisions reflected the inherent maturity levels of the persons depicted. Reaction times in the paired comparison paradigm increase with task difficulty (i.e., the similitude of picture). Both male and female judges were able to differentiate between stimuli from the opposite sex in terms of age; the perception of the stages of pubertal development conformed to a measurement on a ratio scale. Similarly, the decisions on attractiveness of the categories were in accordance with a ratio scale. Male participants favored adolescent and adult female stimuli. Contrary to expectation, female participants did not show a preference for any single age category. Heterosexual university students (52 females and 50 males) participated in the paired comparison task, deciding which of the persons shown in two pictures was younger and which one was more attractive. Reaction times were also recorded. 2 tables, 2 figures, and 37 references