Influencing Postauricular Reflex Magnitude Using Reward in a Motivational Task

Abstract

This study investigates the magnitude of the post-auricular muscle reflex (PAMR) in response to feedback about low and high rewards in order to determine whether the reflex could be used as an implicit measure of individual reward perception. The PAMR was elicited by administering rapid click sounds and recorded with an electromyograph. Meanwhile, participants (N = 32) had to complete a reaction time task in which they could either increase, maintain or decrease their score. Obtaining a higher score would lead to a higher monetary reward. The rewards and losses were each divided into a high and a low level. We found that feedback about a loss and reward elicits a significantly stronger PAMR magnitude than neutral feedback, indicating that the reflex reacted to mutual properties of reward and loss stimuli. It was further found that gaining high rewards affects the PAMR more strongly than gaining low rewards. The study proposes that reward and loss are similar in motivation and arousal properties, which could be the underlying factors influencing the PAMR magnitude. Derived from that, higher motivation and arousal could lead to increases in PAMR magnitude.