Combined influence of valence and statistical learning on the control of attention: Evidence for independent sources of bias.

Selection history exerts a powerful influence on the control of attention. Stimuli signalling reward and punishment capture attention even when physically non-salient and task-irrelevant. Repeated presentation of a salient distractor at a particular location generates learned suppression, resulting in reduced attentional processing at that location. A debate in the field concerns whether different components of selection history influence attention via a common underlying mechanism of learning-dependent control or via distinct, independent mechanisms. We probed this question with a particular focus on reward/punishment history and learned suppression. Participants were trained to suppress a particular location (high probability distractor location) and associate colours with reward or no outcome (no-reward). In a subsequent task, reward and no-reward distractors appeared in all locations equally often. In a separate experiment, we replaced reward with electric shocks. Reward and shock distractors captured attention more strongly than no-reward and no-shock distractors irrespective of their location. Distractors appearing in the high probability location showed reduced capture irrespective of their type. The results imply that reward and punishment learning and learned suppression have independent influences on the attentional system.