Archives of Sexual Behavior

, Volume 39, Issue 5, pp 1081–1090 | Cite as

Assessment of Pedophilic Sexual Interest with an Attentional Choice Reaction Time Task

  • Andreas Mokros
  • Beate Dombert
  • Michael Osterheider
  • Angelo Zappalà
  • Pekka Santtila
Original Paper


Choice-reaction time (CRT) is an experimental information-processing paradigm. Based on an interference effect in visual attention, the CRT method has been shown to be suitable for measuring sexual orientation in men and women. The present study assessed the potential of the CRT to identify deviant (i.e., pedophilic) sexual interest. Participants were patients from forensic-psychiatric hospitals: 21 child molesters and 21 non-sex offenders. The dependent variable was reaction time in an ostensible seek-and-locate task (i.e., identifying the position of a dot superimposed on a picture of a person). There was an interaction effect between stimulus age category and participant group status: Child molesters took longer to respond to pictures of children relative to pictures of adults. Non-sex offenders showed an opposite pattern (i.e., longer reaction times with pictures of adults than with pictures of children). In addition, the data supported the notion of sexual content induced delay: Subjects took longer for the task with nude stimuli than with clothed ones. A subtractive preference index, derived from the reaction times for child and adult stimulus material, allowed distinguishing participants from both groups almost perfectly (ROC-AUC = .998). We conclude that a match of sexual interest with properties of visual stimuli led to a cognitive interference effect: Attentional resources were drawn from the ostensible task of locating the dot towards exploring the picture. This opens up the possibility of using this interference effect (i.e., the delay of response times) for diagnostic purposes.


Attention Choice reaction time CRT Paraphilia Pedophilia 



This research was supported by an Academy of Finland Grant (121232) to the first, fourth, and last authors and a Center of Excellence Grant from the Stiftelsen för Åbo Akademi Foundation to the last author. Parts of this research were presented at the 8th Annual Conference of the International Association of Forensic Mental Health Services (IAFMHS), Vienna, Austria, July 14–16, 2008, and at the 27th Research and Treatment Conference of the Association for the Treatment of Sexual Abusers (ATSA), Atlanta, October 22–25, 2008. We want to thank Teemu Laine from the University of Turku, Finland, for his invaluable help with programming the stimulus presentation script. None of the authors have any financial interest in or financial conflict with the subject matter or the materials discussed in this article.


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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Andreas Mokros
    • 1
  • Beate Dombert
    • 1
  • Michael Osterheider
    • 1
  • Angelo Zappalà
    • 2
  • Pekka Santtila
    • 2
  1. 1.Department of Medicine, Forensic Psychiatry, and Psychotherapy UnitUniversity of Regensburg, District HospitalRegensburgGermany
  2. 2.Department of PsychologyÅbo Akademi UniversityTurkuFinland

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