Attentional Bias Toward Valued Stimuli:An Engagement Bias

Recent evidence has shown that learning to associate the value of behavioral outcomes with specific stimuli(i.e., value learning/association) can induce attentional capture in a subsequent visual search task. Here we investigated whether such stimuli could yield attentional bias in the dot-probe paradigm. In Experiment 1, participants learned to associate nonsense shape outlines with monetary wins or losses during the training phase, as a result these shapes were reward- or punishment-associated. The shapes were then used as cues in an explicit no feedback dot-probe task. Cues preceded probe targets by 500 ms and appeared at either the salient(congruent trials) or nonsalient location(incongruent trials). Results indicate that participants showed attentional bias toward reward-associated stimuli. RT slowing was found toward punishment-associated congruent trials compared to incongruent trials, which might be a consequence of inhibition of return or attentional avoidance. In Experiment 2, we further investigated the effect of punishment on attention by changing exposure duration of the cues. In addition, we differentiated engagement bias involving rapid direction of attention toward value-associated stimuli and disengagement bias involving slow direction of attention away from value-associated stimuli. The value-learning procedure was the same as in Experiment 1. Interestingly, an engagement bias of attention was detected toward both reward- and punishment-associated stimuli; however, this effect was observed when the exposure duration was 500 ms for reward-associated stimuli and300 ms for punishment-associated stimuli but not observed under other exposure duration conditions. These results demonstrate that value learning can initially orient attention toward motivationally salient stimuli, irrespective of valence. In experiment 3,ERP ware used to investigate the underlying mechanism of attentional bias towardvalue-associated stimuli. Results showed that both reward- and punishment-associated stimuli induced N2 pc at an early stage of 160-190 ms, while only reward-associated stimuli induced N2 pc at an late stage of 280-350 ms. We suggest that the learned value association acts to change visual salience of stimuli which leads to automatically attentional orientation toward these stimuli in visual selective attention.