“Not ready to sort it yet”: revised reinforcement sensitivity theory (rRST) predicts left-handed behavioural inhibition during a manual sorting task

Wright, Hardie, and Rodway (2004) showed that left-handers were slower to respond initially to the Tower of Hanoi, and proposed that this was due to either anxious or inhibited behaviour in their approach or to right hemisphere superiority in spatial tasks. The revised reinforcement sensitivity theory (Gray & McNaughton, 2000) offers a rationale for the influence of anxiety, and Wright, Hardie, and Wilson (2009) demonstrated a behavioural inhibition system (BIS) difference related to handedness, arguing that, due to their increased BIS sensitivity, left-handers may show more anxiety-induced goal conflict and should take longer to initiate any novel task. On the basis of this, the current study tested the prediction of increased left-handed inhibition of action, using a manual sorting task. A total of 78 participants took part and analyses revealed that left-handers took significantly longer to move the first card. A significant handedness×sex interaction was found for task completion time. The significant initiation difference further supports the idea that rBIS sensitivity differences may be the source of divergent responses in novel tasks, rather than hemispheric dominance related withdrawal (Davidson, 1995), and provides support for the new role of BIS in the revised rather than original reinforcement sensitivity theory (Gray, 1982).