Trait BIS Predicts Alpha Asymmetry and P300 in a Go/No-Go Task JAN WACKER * , MIRA-LYNN CHAVANON, ANJA LEUE and GERHARD STEMMLER Department of Psychology, Philipps-Universita ¨ t, Marburg, Germany Abstract Inspired by the revised Behavioural Inhibition System (BIS) theory the present study probed the association between individual differences in Trait BIS and electroencephalo- gram indicators of conflict processing/inhibition. Sixty-nine male participants either high or low in Trait BIS completed a Go/No-Go task while the electroencephalogram was recorded. As expected, Trait BIS was associated with the No-Go-anteriorisation of the P300 event-related potential (i.e. an index of response inhibition presumably generated in the dorsal anterior cingulate—an area implicated in conflict processing) and with No- Go-related changes towards left frontal alpha activity (i.e. presumably more activity in right prefrontal cortex— an area implicated in response inhibition). These findings support the role of conflict processing attributed to BIS functioning in the revised theory. Copyright # 2009 John Wiley & Sons, Ltd. Key words: electroencephalography; behavioural inhibition; behavioural activation; anxiety; frontal asymmetry; laterality; event-related potentials; P300 INTRODUCTION Prominent biologically oriented personality theories converge on Gray’s (1970) idea that certain important dimensions of personality reflect inter-individual variation in the sensitivity of neurobehavioural systems concerned with approach (or behavioural activation) and avoidance (or withdrawal or behavioural inhibition) engaged by reinforcing stimuli in the environment (for a comprehensive review see the volume edited by Corr, 2008). In the revised version of his own ‘reinforcement sensitivity theory’ Gray postulated that goal-directed behaviour is governed by three such systems (J.A. Gray & McNaughton, 2000): The Behavioural Activation System (BAS) is activated by rewarding stimuli, modulates approach motivation toward such stimuli and increases positive affect (e.g. European Journal of Personality Eur. J. Pers. 24: 85–105 (2010) Published online 18 September 2009 in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/per.740 *Correspondence to: Jan Wacker, Department of Psychology, Philipps-Universita ¨t, Gutenbergstr. 18, D-35032 Marburg, Germany. E-mail: wackerj@staff.uni-marburg.de Copyright # 2009 John Wiley & Sons, Ltd. Received 20 January 2009 Revised 15 July 2009 Accepted 11 August 2009