Research has found that child molesters (both pedophilic and non-pedophilic) tend to have poorer executive functioning (EF), particularly inhibition, as compared to other types of criminal offenders (Eastvold, Suchy, Strassberg, & 2011; Suchy, Whittaker, Strassberg, & Eastvold, 2009). Poorer performance on measures of inhibition may have different mechanisms for pedophilic child molesters (PCM; i.e., those offenders who are sexually attracted only to children) than non-pedophilic child molesters (N-PCM; i.e., those offenders whose sexual attraction is not limited to children). Specifically, poor inhibition in PCM may be explained by slower processing speed (Suchy, et al., 2009; Suchy, Eastvold, Strassberg, & Franchow, 2014), whereas it may be explained by impulsive errors in N-PCM (Eastvold, Suchy, & Strassberg, 2011). Intraindividual variability (IIV) refers to transient, short-term fluctuations in performance (Nesselroade, 1991). IIV is sometimes interpreted as a measure of cognitive control, an aspect of EF that could impact performance speed and accuracy due to poorer focus.

Greater IIV also appreas to be associated with greater vulnerability to EF depletion after behavioral inhibition (DesRuisseaux, Suchy, & Franchow, 2021), which could represent a mechanism whereby vulnerability to EF depletion could be a precursor of offense. However, given that poor performance on measures of inhibition seem to have different underlying mechanisms for PCM and N-PCM, it is unclear whether both groups would exhibit greater IIV compared to non-sexual offenders.

Participants were PCM (n = 76, M age = 33.61(7.74), Range = 1947; 92.1% White, 2.6% Hispanic/Latino, 2.6% Native American, 1.3% Black, 1.3% Other), N-PCM (n = 52, M age = 30-88(6.37), Range = 2045; 73.1% White, 13.5% Hispanic/Latino, 7.7% Other, 3.8% Native American, 1.9% Black), and non-sexual offenders (n = 25, M age = 29.96(8.16), Range = 22-45; 80% White, 8% Hispanic/Latino, 8% Other, 8% Asian) recruited as part of two larger studies examining cognition in sex offenders. IIV was assessed using the Push-Turn-Tap-Tap (PTT) task, an experimental computerized measure of EF from which IIV can be calculated (DesRuisseaux et al., 2021).

Independent samples t-tests found that both PCM and N-PCM had greater IIV than nonsexual offenders (t(99) = 2.13, p = .04; t(75) = 2.23, p = .03, respectively). Even on their fastest responses, PCM had greater time elapsed between correct sequences (i.e., slower response style; t(126) = 2.23, p = .03) than N-PCM. There were no significant differences in error rates between any groups (p > .05).

These results suggest that IIV varies between sexual and non-sexual offenders but does not vary between PCM and N-PCM. This is consistent with prior research suggesting that both PCM and N-PCM have poorer EF than non-sexual offenders. Additionally, consistent with prior research, PCM had a slower response style than N-PCM and non-sexual offenders. Unlike prior research that has found significant differences in accuracy rates between PCM and N-PCM, the present results did not find a significant difference. Since IIV has been associated with increased likelihood of EF depletion (likely increasing risk of lapses), future research could examine whether CM with greater IIV have an increased likelihood of reoffending.