The following excerpt is taken from “A Profile of Pedophilia: Definition, Characteristics of Offenders, Recidivism, Treatment Outcomes, and Forensic Issues” by Ryan C. W. Hall, MD, & Richard C.W. Hall, MD. Originally published by MAYO CLINIC PROCEEDINGS.

Detecting Pedophiles for Research Purposes
Historically, for research purposes, the most reliable mechanism for determining pedophilia is by use of phallometric or plethysmographic testing procedures. These procedures involve presenting various types of stimuli (pictures, movies, audio tapes) to the subject and then measuring either blood volume changes or circumference changes of the penis. Volumetric changes in penile blood are generally thought to be more accurate in determining lower levels of sexual responses or arousal than circumference measurements. The problems with plethysmography are that it is invasive and expensive, requires the presence of sexually explicit material, is not applicable to females, requires functioning male genitalia (medical cause of impotence, such as hypertension or diabetes, could affect results), and can potentially be tricked (eg, by looking at images but thinking about something else). An additional limiting factor to the current use of plethysmography in pedophilic research in the United States is that the images of “sexually explicit material of children” needed to perform the test are themselves considered illegal by most state laws and under federal pornography guidelines. Possession of such material can lead to legal trouble for researchers.

A relatively new testing procedure known as the Abel Assessment for Sexual Interest (AASI) is beginning to be used in conjunction with or in lieu of traditional phallometric measurements. The AASI is based on a self-report questionnaire and computer-based visual reaction times, which measure how long a subject looks at various clothed photographs of a standardized sample of children and adults. The AASI is reported to be able to discriminate 21 sexual interest categories and has been shown to be as valid as plethysmography for detecting homosexual pedophiles. The AASI has better validity for detecting heterosexual hebophiles than plethysmography but is not accurate for pedophiles interested in young girls. Although not foolproof, the advantages of the AASI are that it uses standardized nonpornographic photographs, requires only 1 to 2 hours to administer, requires no special equipment except a computer, can be performed almost anywhere, and is less invasive and intrusive to the subject than plethysmography. . . . Continue Reading →