We sought to explore the interaction of the impulsivity trait with response uncertainty. To this end, we used a reaching task (Pellizzer and Hedges in Exp Brain Res 150:276-289, 2003) where a motor response direction was cued at different levels of uncertainty (1 cue, i.e., no uncertainty, 2 cues or 3 cues). Data from 95 healthy adults (54 F, 41 M) were analysed. Impulsivity was measured using the Barratt Impulsiveness Scale version 11 (BIS-11). Behavioral variables recorded were reaction time (RT), errors of commission (referred to as 'early errors') and errors of precision. Data analysis employed generalised linear mixed models and generalised additive mixed models. For the early errors, there was an interaction of impulsivity with uncertainty and gender, with increased errors for high impulsivity in the one-cue condition for women and the three-cue condition for men. There was no effect of impulsivity on precision errors or RT. However, the analysis of the effect of RT and impulsivity on precision errors showed a different pattern for high versus low impulsives in the high uncertainty (3 cue) condition. In addition, there was a significant early error speed-accuracy trade-off for women, primarily in low uncertainty and a 'reverse' speed-accuracy trade-off for men in high uncertainty. These results extend those of past studies of impulsivity which help define it as a behavioural trait that modulates speed versus accuracy response styles depending on environmental constraints and highlight once more the importance of gender in the interplay of personality and behaviour.
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Acknowledgments We would like to thank Prof. Guy Goodwin (University of Oxford Dept of Psychiatry) for comments on an early version of the manuscript, Mr. Dale Boeff (Brain Sciences Center, Minneapolis VA Medical Center) and Dr. Sven Braeutigam (Oxford Center for Human Brain Activity) for technical assistance and Dr. Anling Rao (Oxford Center for Human Brain Activity) for help with data collection. CT and this study were supported by an MRC research training fellowship (MRC award G0802327), and in part by a VA Merit grant from the U.S. Department of Veterans Affairs (to GP), a startup grant from the John Fell Fund (Oxford University Press) and an NIHR (UK) Academic Clinical Fellowship.
- Barratt impulsiveness scale
- Gender differences