Charles University Prague, Czech Rep. Raculty of Philosophy Department of Psychology Doctoral Theses Comparison of Accuracy and Precision of Sexodiagnostic Methods of Penile Plethysmography and Viewing Time Ondřej Trojan, 2017 Abstract The diagnosis of pedophilia denotes (according to ICL 10) the erotic preference for prepubescent or early pubescent children. Penile plethysmography (PPG) measures the reaction of these men in respon- se to either visual stimuli or to erotic narrative stories including child objects. Penile plethysmography is quite an intrusive assessment method, so viewing time (VT) might be a good alternative if it is shown to be compapratively accurate. Several studies in the past have shown inconsistent data, therefore more research is needed to confirm its validity in distinguishing responses to the preferred age category of pedophilic men. Method: Participants were 30 self-referred admitting paedophiles aged between 18 and 55 in the experimental group and 30 heterosexual gynephile men in the comparison group. A set of photographs depicting naked adults in addition to male and female children across 6 age categories ranging from young infants to adolescents was used; the same set of 38 stimuli were used to measure PPG (first) and VT(after). PPG apparatus was used to measure penile...

This study investigated distortion that occurs when raw scores are converted to ipsative scores on Affinity 2.0, a relatively new instrument for assessing sexual interest. Using a sample of 146 non-offending, heterosexual females, this study examined the characteristics of distorted ipsative score profiles and attempted to develop an algorithm to identify such distortions. A method was developed for defining distortion objectively. Of the 146 profiles,125 were found to contain some degree of distortion. Several hypotheses were formulated as to variables that might be related to distortion. These relationships were examined using Pearson Product Moment Correlations. Several statistically significant, but weak, correlations were found. An interaction effect was calculated for four of these variables, and was found to have a moderately strong correlation with distortion (r = .530, p <.01). An algorithm for identifying distortion was developed using this interaction effect. Several cut-off scores were tested. The most effective cut-off only correctly identified 42.9% of the significantly distorted profiles. Implications and limitations of the results are discussed, and directions for future research are provided.

Affinity 2.5 is a computer-based instrument designed to measure sexual interest using viewing time of images depicting fully-clothed males and females of different ages. Participants are asked to rate the sexual attractiveness of the person in the image according to a 15-point scale while their viewing time of each image is surreptitiously monitored. The validity of viewing time as a measure of sexual interest is based on social cognition theory and is established in the review of literature. The number of images comprising Affinity 2.5 represents a 42.9% increase from the previous version of the assessment, Affinity 2.0. The purpose of this study was to examine the temporal stability of scores on Affinity 2.5 for a sample of exclusively heterosexual, nonpedophilic males and females. Viewing time data from 63 males and 84 females were analyzed using a chi-square procedure. Results of this analysis indicate that 86% of responses from the male participants and 88% of responses from the female participants were consistent from time one to time two. As suspected, these percentages represent an increase in reliability over the temporal stability of the shorter Affinity 2.0.