Indirect behavioral measures of cognition among sexual offenders

What can the eyes tell us about atypical sexual preferences as a function of sex and age? Linking eye movements with child-related chronophilias

Visual attention plays a central role in current theories of sexual information processing and is key to informing the use of eye-tracking techniques in the study of typical sexual preferences and more recently, in the study of atypical preferences such as pedophilia (prepubescent children) and hebephilia (pubescent children). The aim of this theoretical-empirical review is to connect the concepts of a visual attention-based model of sexual arousal processing with eye movements as indicators of atypical sexual interests, to substantiate the use of eye-tracking as a useful indirect measure of sexual preferences according to sex and age of the stimuli. Implications for research are discussed in terms of recognizing the value, scope and limitations of eye-tracking in the study of pedophilia and other chronophilias in males and females, and the generation of new hypotheses using this type of indirect measure of human sexual response.

Interference inhibition in offending and non-offending pedophiles: A preliminary event-related fMRI study

The ability to inhibit behavior is thought to be an import skill for avoiding criminal conduct, especially when combined with personal predispositions or criminogenic needs such as a pedophilic preference disorder. While previous research emphasized the relationship between impulsivity and child sexual offending, not pedophilia per se, studies on the underlying neurobiological mechanisms in subdomains of impulsivity remained scarce. Here, we focused on interference inhibition and examined event-related functional magnetic resonance imaging (fMRI) data of three groups of men performing a color-word Stroop task: (1) pedophiles with a history of CSO (P+CSO, n = 11), (2) pedophiles without a history of CSO (P-CSO, n = 8) and (3) non-pedophilic, non-offending healthy controls (HC, n = 10). On the behavioral level, P+CSO revealed increased Stroop interference as compared to P-CSO and HC. Moreover, increased Stroop interference in P+CSO was accompanied by enhanced conflict-related activity in left superior parietal cortex and precentral gyrus as compared to P-CSO. Albeit behavioral analyses of error and post-error processing revealed no significant between-group differences, P-CSO showed increased post-error-related activity in left posterior cingulate, precuneus and middle temporal gyrus as compared to P+CSO. Our preliminary data highlight inhibition deficits in offending as compared to non-offending pedophiles or healthy men and suggest that functional alterations in attention reallocation and impulse suppression/control may moderate the risk for committing CSO in men suffering from pedophilia.

A Preliminary Investigation Into a Range of Implicit and Explicit Offense Supportive Cognitions in Perpetrators of Physical Intimate Partner Violence

The current study assessed a wide range of offense supportive cognitions in relation to the perpetration of physical intimate partner violence (IPV). This research used both implicit and explicit measures in a U.K. sample of 19 male IPV perpetrators recruited from a community-based IPV intervention program and 20 men from the community with no history of IPV. The study also explored the ability of the implicit measures to differentiate between the two groups. The cognitions assessed included gender-role stereotype, attitudes condoning violence against a partner, attitudes condoning violence in general, hostile attitudes toward women, sense of entitlement in the relationship and over the intimate partner (control and dominance), and general sense of entitlement. Participants completed a number of established self-report measures and a series of computer-based reaction time tasks including two implicit association tests, one go/no-go association task, and four sentence judgment tasks. Significant group differences emerged across all measures both at the explicit and at the implicit level. Most implicit measures had very good discriminatory power, and the combination of all implicit measures showed excellent discriminatory power, equal to that of the explicit measures combined. These findings suggest that some IPV perpetrators hold offense supportive cognitions that may have become fairly well established and have started to operate at an automatic level. Implicit measures could be useful tools for risk assessment purposes and identification of treatment needs alongside already established measures.

The Development and Validation of the Cognitions of Internet Sexual Offending (C-ISO) Scale

Tools designed to measure the cognitions of individuals who engage in sexual activities with children over the Internet are either based on knowledge about men who had committed contact sexual offenses or cognitive phenomena not specifically associated to offending behaviors. Thus, there is no validated tool specifically designed to assess the offense-supportive cognitions of men who use the Internet to sexually offend children. This study developed and validated the Cognitions of Internet Sexual Offending (C-ISO) scale. A sample of 241 men with online and contact sexual as well as with nonsexual offenses completed the C-ISO scale and its psychometric properties, and latent structure was analyzed using both Classical Test Theory (CTT) and Item Response Theory (IRT), resulting in a final version containing 31 items. The analyses indicate that the C-ISO has excellent psychometric properties and discriminates men with online sexual offenses from those with contact sexual and nonsexual offenses. Implications of the findings for clinical practice and future research are discussed.

The Effects of Acute Transcranial Direct Current Stimulation on Attentional Bias in Pedophilic Disorder: A Preregistered Pilot Study

OBJECTIVES

Individuals with pedophilic disorder (PD) experience personal and interpersonal difficulties and are at risk of sexually offending against children. As such, innovative and empirically validated treatments are needed. Recent studies have indicated that men who have sexually offended against children (SOC) with PD display an automatic attention bias for child-related stimuli as well as reduced activity in the dorsolateral prefrontal cortex (dlPFC), a brain area involved in cognitive control, including control over sexual arousal. In this preregistered pilot study, we are the first to investigate whether acutely increasing prefrontal activity could reduce the putative pedophilic attention bias.

MATERIALS AND METHODS

We delivered a single 20-min session of active anodal versus sham transcranial direct current stimulation (tDCS) over the left dlPFC to 16 SOC with PD and 16 matched healthy controls, while they performed a task requiring controlled attention to computer-generated images of clothed and nude children and adults. We collected responses unobtrusively by recording eye movements.

RESULTS

Our results did not support the presence of the expected automatic attention bias across outcome measures. Nonetheless, we found a response facilitation with child targets in patients and, unexpectedly, in controls, likely due to unwanted salience effects. Active versus sham tDCS reduced this bias across groups, as indicated by a significant group*condition interaction (p = 0.04). However, no attentional bias and no tDCS effects on attentional responses to child and adult images emerged following tDCS.

CONCLUSIONS

These results suggest enhanced cognitive control in response to salient stimuli during active tDCS. Thus, to assist future studies on neuromodulation in PD, we provide suggestions for design improvement.

Sexual Attraction to Both Genders in Ambiphilic Men: Evidence from Implicit Cognitions

Ambiphilic (or bisexual) men describe feelings of sexual attraction to both men and women. However, physiological measures of arousal have failed to show a consistent pattern of arousal to both genders. We measured men's automatic associations between the concept of sex (represented by words) and the concepts of men versus women (represented by images) via the Implicit Association Test (IAT) and a priming task. On the IAT, gynephilic men (N = 32) were faster for women-sex pairings, androphilic men (N = 18) were faster for men-sex pairings, while ambiphilic men (N = 20) showed no bias toward either gender. We then isolated the concepts of "men" and "women" by comparing them separately against neutral images. In contrast to both the gynephilic or androphilic men, ambiphilic men showed sexual associations to both men and women. On the priming task, ambiphilic men showed faster responses to sex words, but slower responses to not-sex words, when primed with pictures of either men or women compared to when primed by neutral images. The results from all the experimental tasks suggest that ambiphilic men have a pattern of sexual association that is different from both gynephilic and androphilic men and represents a sexual attraction to both men and women.

Tracking Mouse Trajectories Related to Decisions About Sexual Interest

The current research explored continuous behavioral processes by recording participants' hand movements toward a response option using Mousetracker software. Across three studies, we tested the idea that sexual interest-related decisions can be indexed using automatic movements. Using a UK sample of self-identified same- and opposite-gender attracted men (N = 43), Study 1 showed that the process of approaching the response button was faster, more direct, and less curved when participants responded from their own (vs. a non-preferred) perspective. Study 2 supported these findings using a German sample of self-identified same- and opposite-gender attracted men (N = 66). Using a teleiophilic sample of 100 self-identified opposite-gender attracted men (n = 51) and women (n = 49), Study 3 examined age-specific sexual interests (i.e., responding to stimuli from a pedophilic and a teleiophilic perspective). As expected, in the teleiophilic block, participants' responses were faster, more direct, and less curved than in the pedophilic block. Collectively, the results suggest that mousetracking shows promise as a measure of sexual interest (across the dimension of both gender and age), providing grounds for future research.

Differences in Visual Attention Patterns to Sexually Mature and Immature Stimuli Between Heterosexual Sexual Offenders, Nonsexual Offenders, and Nonoffending Men

Men, whether gynephilic or androphilic, show both early and late attention toward adults and not toward children. We examined early and late visual attention to sexually mature versus immature stimuli in four groups of heterosexual men: sexual offenders against children (SOAC = 18), sexual offenders against adults (SOAA = 16), nonsexual offenders (NSO = 18), and nonoffending men (NOM = 19). We simultaneously presented adult and child stimuli and measured time to first fixation, number of first fixations, total duration of fixation, and fixation count to four areas of interest: entire body, then face, chest, and pelvis. We found a significant interaction where only SOAC tended to fixate more first times to child than to adult stimuli. Conversely, we found longer total duration of fixations for the bodies of adults compared to the bodies of children in all groups; however, in both the total duration of fixations and the fixation count for the whole body, but especially in the chest, SOAC tended to fixate longer and more often on child stimuli than the other two groups of offenders, but not longer or more often than NOM. This study adds to the limited research using eye-tracking techniques in samples of SOAC.

Are There Any Biomarkers for Pedophilia and Sexual Child Abuse? A Review

The use of biomarkers in medicine is a common and valuable approach in several clinical fields. Understanding the relationship between measurable biological processes and clinical outcomes not only is indispensable in the face of understanding physiological processes in healthy as well as in diseased organisms but also for understanding and evaluating treatment effects. Therefore, also in the context of forensic psychiatry, biomarkers and their potentially beneficial effects are of growing interest. The objective of this review is to examine if there are biomarkers that may serve as a tool to support diagnostic process, treatment evaluation, and risk assessment of pedophilic individuals and child sexual offenders. In the first part, we present an overview of the current neurobiological, as well as physiological and psychophysiological approaches to characterize pedophilia and child sexual offending. Secondly, we discuss and evaluate the impact of these approaches on the development of biomarkers for diagnosis, therapy, and risk assessment in pedophilic subjects and child sexual offenders. We conclude that a lot of research has already enhanced our neurobiological knowledge about pedophilia and child sexual offending. Although there surely exist promising parameters and approaches, in our view currently none of these is ready yet to serve as a clinically applicable diagnostic, response, or predictive biomarker for pedophilia and child sexual offending. Therefore, further work remains to be done. The development of a composite diagnostic biomarker to assess deviant sexual interest, combining several measures like functional magnetic resonance imaging, electroencephalogram, eye tracking, and behavioral approaches seems to be most promising. A valid and reliable measurement of deviant sexual interest, insensitive to manipulations could significantly support clinical diagnostic process. Similarly, regarding therapy evaluation and risk assessment, a composite biomarker to assess inhibitory control functions seems to be promising. Furthermore, the application of the Research Domain Criteria-approach, a new approach for investigating and classifying mental disorders, offers the possibility to take research to a new level.

Measuring the Cognition of Firesetting Individuals Using Explicit and Implicit Measures

This study examined un-apprehended deliberate firesetters' cognition. Relative to non-firesetters, un-apprehended firesetters reported higher explicitly measured fire interest. However, their reaction times (RTs) on a fire interest implicit LDT were inconsistent with these findings. They did, however, display a pattern of LDT RTs consistent with Dangerous World and Fire is Powerful beliefs.

Assessing Sexual Interest in Children Using the Go/No-Go Association Test

The present study investigated whether a latency-based Go/No-Go Association Task (GNAT) could be used as an indirect measure of sexual interest in children. A sample of 29 individuals with a history of exclusive extrafamilial offenses against a child and 15 individuals with either a history of exclusive intrafamilial or mixed offenses (i.e., against both adults and children) were recruited from a treatment center in the United States. Also, a sample of 26 nonoffenders was recruited from a university in the United Kingdom. All participants completed the Sexual Fantasy-GNAT, a Control-GNAT, and two self-report measures of sexual fantasy. It was hypothesized that, relative to the two comparison groups, the extrafamilial group would respond faster on the block that paired "sexual fantasy" and "children." Also, GNAT scores were expected to correlate with child-related sexual fantasies. Support was found for both hypotheses. Response-latency indices were also found to effectively distinguish the extrafamilial group, as well as those who self-reported using child-related sexual fantasies. The implications of these findings, along with the study's limitations and suggestions for future research, are discussed.

Identifying Pedophilic Interest in Sex Offenders Against Children With the Indirect Choice Reaction Time Task

Abstract. Pedophilia – a disorder of sexual preference with primary sexual interest in prepubescent children – is forensically relevant yet difficult to detect using self-report methods. The present study evaluated the criterion validity of the Choice Reaction Time (CRT) task to differentiate between a sample of child sex offenders with a presumably high rate of pedophilic individuals and three control groups (other sex offenders, non-sex offenders, and community controls, all male; N = 233). The CRT task required locating a dot superimposed on images depicting men, women, girls, or boys and scrambled pictures as quickly as possible. We used two picture sets, the Not Real People (NRP) set and the Virtual People Set (VPS). We predicted sexually relevant pictures to elicit longer reaction times in interaction with the participant group. Both CRTs showed main effects of stimulus explicitness and preferred stimulus gender. The CRT-NRP also yielded an interaction effect of participant group and stimulus maturity while the CRT-VPS showed a tendency in this direction. The overall effect size was moderate. Results offer support for the usefulness of the CRT task in forensic assessment of child sex offenders.

Pupillary Response as an Age-Specific Measure of Sexual Interest

In the visual processing of sexual content, pupil dilation is an indicator of arousal that has been linked to observers' sexual orientation. This study investigated whether this measure can be extended to determine age-specific sexual interest. In two experiments, the pupillary responses of heterosexual adults to images of males and females of different ages were related to self-reported sexual interest, sexual appeal to the stimuli, and a child molestation proclivity scale. In both experiments, the pupils of male observers dilated to photographs of women but not men, children, or neutral stimuli. These pupillary responses corresponded with observer's self-reported sexual interests and their sexual appeal ratings of the stimuli. Female observers showed pupil dilation to photographs of men and women but not children. In women, pupillary responses also correlated poorly with sexual appeal ratings of the stimuli. These experiments provide initial evidence that eye-tracking could be used as a measure of sex-specific interest in male observers, and as an age-specific index in male and female observers.

Pupillary Response as an Age-Specific Measure of Sexual Interest

In the visual processing of sexual content, pupil dilation is an indicator of arousal that has been linked to observers' sexual orientation. This study investigated whether this measure can be extended to determine age-specific sexual interest. In two experiments, the pupillary responses of heterosexual adults to images of males and females of different ages were related to self-reported sexual interest, sexual appeal to the stimuli, and a child molestation proclivity scale. In both experiments, the pupils of male observers dilated to photographs of women but not men, children, or neutral stimuli. These pupillary responses corresponded with observer's self-reported sexual interests and their sexual appeal ratings of the stimuli. Female observers showed pupil dilation to photographs of men and women but not children. In women, pupillary responses also correlated poorly with sexual appeal ratings of the stimuli. These experiments provide initial evidence that eye-tracking could be used as a measure of sex-specific interest in male observers, and as an age-specific index in male and female observers.

Automatic Direction of Spatial Attention to Male Versus Female Stimuli: A Comparison of Heterosexual Men and Women

Abundant research has shown that men's sexual attractions are more category-specific in relation to gender than women's are. We tested whether the early automatic allocation of spatial attention reflects these sexual attractions. The dot-probe task was used to assess whether spatial attention was attracted to images of either male or female models that were naked or partially clothed. In Experiment 1, men were faster if the target appeared after the female stimulus, whereas women were equally quick to respond to targets after male or female stimuli. In Experiment 2, neutral cues were introduced. Men were again faster to female images in comparison to male or neutral images, but showed no bias on the male versus neutral test. Women were faster to both male and female pictures in comparison to neutral pictures. However, in this experiment they were also faster to female pictures than to male pictures. The results suggest that early attentional processes reveal category-specific interest to the preferred sexual category for heterosexual men, and suggest that heterosexual women do not have category-specific guidance of attentional mechanisms. The technique may have promise in measuring sexual interest in other situations where participants may not be able, or may not be willing, to report upon their sexual interests (e.g., assessment of paedophilic interest).

Indirect Measurement of Sexual Orientation: Comparison of the Implicit Relational Assessment Procedure, Viewing Time, and Choice Reaction Time Tasks

The present study was conducted to validate an adaptation of the Implicit Relational Assessment Procedure (IRAP) as an indirect latency-based measure of sexual orientation. Furthermore, reliability and criterion validity of the IRAP were compared to two established indirect measures of sexual orientation: a Choice Reaction Time task (CRT) and a Viewing Time (VT) task. A sample of 87 heterosexual and 35 gay men completed all three indirect measures in an online study. The IRAP and the VT predicted sexual orientation nearly perfectly. Both measures also showed a considerable amount of convergent validity. Reliabilities (internal consistencies) reached satisfactory levels. In contrast, the CRT did not tap into sexual orientation in the present study. In sum, the VT measure performed best, with the IRAP showing only slightly lower reliability and criterion validity, whereas the CRT did not yield any evidence of reliability or criterion validity in the present research. The results were discussed in the light of specific task properties of the indirect latency-based measures (task-relevance vs. task-irrelevance).

A multimodal examination of sexual interest in children: a comparison of sex offenders and nonsex offenders

Research and theoretical models have consistently identified sexual interest in children as a key factor involved in child sexual offending. However, there is only moderate agreement in the diagnosis of pedophilia and different assessment methods identify different offenders as pedophiles. The current study examined the discriminative and convergent validity of three different measures of sexual interest in children. Participants included sex offenders and nonsex offenders recruited from federal prisons (i.e., offenders serving sentences of more than 2 years) in Ontario, Canada. Child molesters' responses (n = 35) were not significantly different from nonsex offenders (n = 21) on an implicit measure of sexual interest in children (Sexual Attraction to Children Implicit Association Test [SAC-IAT] d = 0.44, 95% CI [-0.11, 0.99]), but differed on the self-report (Sexual Interest Profiling System; d = 0.83, 95% CI [0.27, 1.39]) and viewing time (d = 1.15, 95% CI [0.54, 1.75]) measures. Findings did not provide clear support for the superiority of a multimodal approach, possibly due to the relatively small sample. More often than not, convergence between the three measures was observed (n = 74). Findings from the present study are an important step toward understanding the relationship between different measures of sexual interest in children and establishing their validity.

Direct and indirect measures of sexual maturity preferences differentiate subtypes of child sexual abusers

To aid risk assessment, management, and treatment planning it is essential to assess child sexual abusers' deviant sexual interests (DSI) and preferences (DSP) for sex with children. However, measurement of DSI/DSP is fraught with psychometric problems. In consequence, research interest has shifted to latency-based indirect measures as a measurement approach to complement self-report and physiological assessment. Utilizing the Explicit and Implicit Sexual Interest Profile (EISIP)-a multimethod approach consisting of self-report, viewing time, and Implicit Association Test (IAT) DSI/DSP measures-we replicated phallometric DSI/DSP differences between child sexual abuser subgroups in a sample of intrafamilial, extrafamilial, and child pornography offenders. DSI/DSP was associated with recidivism risk, offense-behavioral measures of pedophilic interest, and sexual fantasizing. It also negatively correlated with antisociality. Distinguishing between child sexual abuser subtypes and being related to recidivism risk, the EISIP is a useful tool for sexual offender assessments.

The virtual people set: developing computer-generated stimuli for the assessment of pedophilic sexual interest

The implicit assessment of pedophilic sexual interest through viewing-time methods necessitates visual stimuli. There are grave ethical and legal concerns against using pictures of real children, however. The present report is a summary of findings on a new set of 108 computer-generated stimuli. The images vary in terms of gender (female/male), explicitness (naked/clothed), and physical maturity (prepubescent, pubescent, and adult) of the persons depicted. A series of three studies tested the internal and external validity of the picture set. Studies 1 and 2 yielded good-to-high estimates of observer agreement with regard to stimulus maturity levels by two methods (categorization and paired comparison). Study 3 extended these findings with regard to judgments made by convicted child sexual offenders.

Assessment of implicit sexual associations in non-incarcerated pedophiles

Offences committed by pedophiles are crimes that evoke serious public concern and outrage. Although recent research using implicit measures has shown promise in detecting deviant sexual associations, the discriminatory and predictive quality of implicit tasks has not yet surpassed traditional assessment methods such as questionnaires and phallometry. The current research extended previous findings by examining whether a combination of two implicit tasks, the Implicit Association Task (IAT) and the Picture Association Task (PAT), was capable of differentiating pedophiles from non-pedophiles, and whether the PAT, which allows separate analysis for male, female, boy and girl stimulus categories, was more sensitive to specific sexual associations in pedophiles than the IAT. A total of 20 male self-reported pedophiles (10 offender and 10 non-offenders) and 20 male self-reported heterosexual controls completed the two implicit measures. Results indicated that the combination of both tasks produced the strongest results to date in detecting implicit pedophilic preferences (AUC = .97). Additionally, the PAT showed promise in decomposing the sexual associations in pedophiles. Interestingly, as there was an equal distribution of offenders and non-offenders in the pedophile group, it was possible to test for implicit association differences between these groups. This comparison showed no clear link between having these implicit sexual associations and actual offending.

Computerized assessment of pedophilic sexual interest through self-report and viewing time: reliability, validity, and classification accuracy of the affinity program

Affinity is a computerized assessment tool that combines viewing time and self-report measures of sexual interest. The present study was designed to assess the diagnostic properties of Affinity with respect to sexual interest in prepubescent children. Reliability of both self-report and viewing time components was estimated to be high. The group profile of a sample of pedophilic adult male child molesters (n = 42, all of whom admitted their offenses) differed from the group profiles of male community controls (n = 95) and male nonsexual offenders (n = 27), respectively. More specifically, both ratings and viewing times for images showing small children or prejuvenile children were significantly higher within the child molester sample than in either of the other two groups, attesting to the validity of the measures. Overall classification accuracy, however, was mediocre: A multivariate classification routine yielded 50% sensitivity for child molester status at the cost of 13% false positives. The implications for forensic use of Affinity are discussed.

Implicit sexual associations in heterosexual and homosexual women and men

Patterns of genital arousal to sexual stimuli are somewhat different between men and women. Heterosexual males and homosexual males show clear category specific arousal that is consistent with their self-reported sexual preference. However, heterosexual women do not show this category specificity. In the present study, we attempted to measure a person's automatic appraisals of stimuli with respect to the concept of sex via the use of implicit measures (the Implicit Association Test and the priming task). In three experiments, we showed that heterosexual females did not show a sex-related category specific response in favor of male versus female stimuli. However, this lack of specificity was not due to a lack of sex-related appraisals, but by equal appraisals of both male and female stimuli. On the other hand, heterosexual men, homosexual men, and homosexual women all showed automatic sex-related appraisals of stimuli that were category specific and in line with their self-reported sexual preference. The study shows difference in the pattern of sexual interest between genders at the earliest stages of the evaluation of a stimulus.

The Validity of Implicit Association Test (IAT) measures of sexual attraction to children: a meta-analysis

The current study presents a quantitative review of the discriminative and convergent validity of Implicit Association Test (IAT) measures adapted to assess sexual interest in children. IAT measures were able to distinguish sex offenders against children (SOC) from non-SOC (M weighted d from random-effects = 0.63, 95 % CI [0.42-0.83], N = 707, k = 12). The largest group differences were found between SOC and non-offenders, followed by non-sex offenders and rapists. IAT measures using sex versus not sex (and similar attribute categories, such as sex vs. neutral) provided superior discrimination compared to IAT measures using sexy versus not sexy (and similar attribute categories, such as erotic vs. non-erotic). The IAT measures had a moderate relationship to self-report (r = .27, 95 % CI [.13-.40], N = 182), sexual offense history variables (r = .27, 95 % CI [.08-.43], N = 145), and viewing time (r = .30, 95 % CI [.16-.43], N = 180) measures of sexual interest in children. Although these IAT measures can discriminate between groups and show convergence with other measures of sexual interest, a better understanding of the construct validity of these tools is required before their use in the assessment, treatment, and supervision of sex offenders.

Attitudes supportive of sexual offending predict recidivism: a meta-analysis

Attitudes supportive of sexual offending figure prominently in theories of sexual offending, as well as in contemporary assessment and treatment practices with sex offenders. Based on 46 samples (n = 13,782), this meta-analysis found that attitudes supportive of sexual offending had a small, yet reasonably consistent, relationship with sexual recidivism (Cohen's d = .22). To the extent that differences were observed, attitudes predicted recidivism better for child molesters than for rapists. There was no difference in the predictive accuracy of attitudes assessed at pretreatment or at posttreatment. The current study indicates that attitudes supportive of sexual offending is a psychologically meaningful risk factor for sex offenders. However, given that many different constructs have been designated as sex offender attitudes, further research and theory is needed to understand how these various constructs contribute to recidivism.

Diagnostic accuracy of eye movements in assessing pedophilia

INTRODUCTION

Given that recurrent sexual interest in prepubescent children is one of the strongest single predictors for pedosexual offense recidivism, valid and reliable diagnosis of pedophilia is of particular importance. Nevertheless, current assessment methods still fail to fulfill psychometric quality criteria.

AIMS

The aim of the study was to evaluate the diagnostic accuracy of eye-movement parameters in regard to pedophilic sexual preferences.

METHOD

Eye movements were measured while 22 pedophiles (according to ICD-10 F65.4 diagnosis), 8 non-pedophilic forensic controls, and 52 healthy controls simultaneously viewed the picture of a child and the picture of an adult. Fixation latency was assessed as a parameter for automatic attentional processes and relative fixation time to account for controlled attentional processes.

MAIN OUTCOME MEASURES

Receiver operating characteristic (ROC) analyses, which are based on calculated age-preference indices, were carried out to determine the classifier performance. Cross-validation using the leave-one-out method was used to test the validity of classifiers.

RESULTS

Pedophiles showed significantly shorter fixation latencies and significantly longer relative fixation times for child stimuli than either of the control groups. Classifier performance analysis revealed an area under the curve (AUC) = 0.902 for fixation latency and an AUC = 0.828 for relative fixation time. The eye-tracking method based on fixation latency discriminated between pedophiles and non-pedophiles with a sensitivity of 86.4% and a specificity of 90.0%. Cross-validation demonstrated good validity of eye-movement parameters.

CONCLUSIONS

Despite some methodological limitations, measuring eye movements seems to be a promising approach to assess deviant pedophilic interests. Eye movements, which represent automatic attentional processes, demonstrated high diagnostic accuracy.