Pedophiles identified accurately with implicit association tasks

Psychologists at Radboud University Nijmegen have published their findings in the journal Archives of Sexual Behavior (online on April 24^th).

This study was the first to work with paedophilic men who were not imprisoned or confined for involuntary psychiatric treatment in a clinic. It reported a highly significant effect: the tests distinguished the paedophile group from the controls with more than 90 per cent accuracy. Furthermore, in both groups of subjects (paedophiles and heterosexual non-paedophiles) one of the tasks (the Picture Association Task, see below) indicated positive as well as negative associations with sex with either children under twelve or adult women. Stated another way: the test showed that paedophiles not only have positive associations with children and sex, but also negative associations with adult women and sex. In the control group, this was the exact opposite.

Motivation for the study

There is growing interest for measuring implicit associations in psychiatry. These are associations that occur automatically, are partly unconscious and hard to repress. The question addressed by the researchers was the following: can such a task be used to detect implicit sexual associations in paedophiles (people with a sexual preference for children) and paedosexuals (people who act according to this preference)?

Novel aspects of the study

In recent years, various studies have been conducted with incarcerated paedosexuals using tasks that measure these implicit sexual associations. The research conducted by the Nijmegen psychologists differs from these studies in two important ways: it used not one task, but a combination of two tasks, and the paedophiles who participated in the study were not incarcerated or involuntarily committed to a clinic. In any case, that was the situation at the time of the study; one of the subjects had previously been incarcerated.

Study participants

The participants in the study were all men, as paedophiles are usually male. Through an association of self-proclaimed paedophiles, the researchers recruited 20 paedophile participants. Half of this group reported that they were paedophile, but not paedosexual; the other half of the group (under conditions of strict anonymity) reported having sexual experiences with children. A group of 20 self-reported heterosexual men were recruited as a control group. They were comparable in terms of age and education level, but reported no sexual associations with children. Both groups understood that they were participating in a study on implicit sexual associations with children.

Methods

Both tasks used in the study have the aim of ascertaining implicit associations. In the first task, the subjects listened to 20 neutral words (such as earth, beige, theory, store) combined randomly with sex-relevant words (such as erection, nude, love, caressing) and 20 pictures of adults (males and females) and children. By clicking on a left or right button, the subjects were asked to classify whether each picture was sex-relevant or neutral, and adult or child. For example, if the left button had to be pressed for sex-relevant and child, for the paedophile participants this was a congruent association, and for participants in the control group this was incongruent. This difference was shown by their reaction times. The faster one is combining two different categories (children and sex on the same button), the stronger the association between these concepts.

The structure of the Picture Association Task was comparable. Neutral or sex-related words were presented on top of pictures of adult women or men or boys or girls (all wearing swimwear). The participants were asked to ignore the background and to categorise the words as quickly as possible.

By combining the two tasks, the distinction between the paedophile group and the control group, based on implicit associations, was more than 90 per cent accurate. Within the group of paedophile participants, no distinction could be made between the results of the self-identified paedophile and paedosexual participants.

Future research and application

Because the results of this 'combination task' are so accurate, the researchers expect interest in the diagnostic use of this approach. For example, it could be used to determine the implicit sexual associations of men who have applied to work with children. However, according to lead researcher Matthijs van Leeuwen, such applications should be used cautiously. 'Firstly, this study concerns a single test involving 40 male participants. Although the results were encouraging, and the number of participants was high enough to test this method, for greater certainty the study should be repeated with a larger group. Secondly, even a very high level of certainty does not mean that a task is fool proof: you can classify a person incorrectly. And thirdly, can you really disqualify people from certain professions because of their thoughts? This is an ethical-legal aspect, which should be studied carefully by others.'

'Therefore, more research is necessary', states the second author, Rick van Baaren. 'We would very much like to work together with other parties on follow-up research and consider the societal implications of this study.'