Motivational incentives improve working memory performance by enhancing memory-based representations rather than altering response strategies

Motivational incentives have been shown to boost working memory (WM) performance when individual items have varying values. However, the extent to which incentives enhance performance when all items possess equal value, and the underlying mechanism, remains uncertain. Two possible explanations for the improvements could be the formation of stronger memory-based representations or the adoption of a speed-accuracy trade-off, wherein incentives lead to slower, more cautious responses without improving memory itself.

To examine these hypotheses, researchers conducted two experiments utilizing an auditory WM task. In the first experiment, participants were allowed to resubmit their responses if they so desired. The findings revealed that reward-related improvements in WM performance were only observed under high memory loads and at serial positions associated with increased interference.

Moreover, these enhancements were distinct from any systematic response slowing or resubmission behavior, suggesting the benefits of incentives were not merely due to cautious response strategies.

Experiment 2 further reinforced the findings from Experiment 1. In this scenario, motivational incentives continued to produce improvements in WM performance even when strict response deadlines were imposed, leaving no room for increased accuracy to substitute for speed. Computational modeling further elucidated that motivational incentives selectively enhanced the precision of memory-based responses, without reducing the reliance on guessing.

The combined results of these experiments indicate that motivational incentives positively impact WM performance by improving the quality of memory-based representations, rather than through strategic slowing or alterations to response strategies.