Reinforcement sensitivity of sex offenders and non-offenders: an experimental and psychometric study of reinforcement sensitivity theory.

This study tested predictions of Gray's Reinforcement Sensitivity Theory (RST) in subgroups of sex offenders and male non-offenders using an experimental choice task consisting of a reward and a non-reward phase. In addition, RST-related psychometric measures were used. Both experimental and psychometric data were of interest to determine whether sex offenders could be reliably differentiated from non-offenders. Paraphilic (N=50) and impulse control-disordered (N=48) sex offenders showed greater sensitivity to continuous reward than male non-offenders (N=51). Impulse control-disordered sex offenders showed less behavioural adaptation under non-reward than both paraphilic sex offenders and male non-offenders. In addition, reward sensitivity, rash-spontaneous impulsivity, and anxiety measures discriminated sex offenders from male non-offenders. The results suggest that reinforcement sensitivity is a promising personality trait for differentiating subgroups of sex offenders from non-offenders. The experimental and psychometric results illustrate that predictive accuracy in forensic settings could be improved by combining several types of data.