Abstract
Introduction: Stimuli that reliably herald the availability of rewards or punishers can acquire motivational salience potentially enhancing their ability to disrupt appropriate allocation of attention. Currently, it remains unclear whether reward effects on visual processing and any hemispheric asymmetry thereof are specific to the positive valence of outcomes (gain vs loss) or more generally reflect motivational salience (stimuli that are highly predictive of outcomes). Method: To investigate we asked participants to learn to associate specific stimuli (faces in Experiment 1 & 2; chairs in Experiment 3) with modest monetary rewards or punishers that occurred with either a high or low probability. Then we centrally presented one of these stimuli (for 85 ms) just (100 ms) prior to a simple letter visual search task. Participants were required to detect the target by pressing the corresponding key while ignoring the value-learned stimuli. Results: Face distractors that had previously been highly predictive of outcomes (rewarding or punishing) versus those less predictive of outcomes slowed subsequent search for targets appearing in the left, but not the right, hemifield (Experiment 1). This finding supports the notion of a right-lateralized, motivational response mechanism that competes for control with non-emotional cognitive processes. The same effect was also observed when distractor stimuli were presented in profile view during the search task but frontally during learning, indicating that motivational salience operates on view-independent representations (Experiment 2); and when face stimuli were replaced with chair stimuli demonstrating that the motivationally induced laterality bias is not dependent on face processing, per se (Experiment 3). Conclusion: Taken together, our new findings reveal that highly motivational salient stimuli (compared to low) preferentially engage a right-hemisphere motivational system, regardless of valence (reward vs punishment), which can in turn impact the recruitment of attentional processes and slow subsequent responses to a neutral visual stimulus.
Meeting abstract presented at VSS 2016