Motivational influences on response inhibition measures.

Psychological research has placed great emphasis on inhibitory control due to its integral role in normal cognition and clinical disorders. The stop-signal task and associated measure--stop-signal reaction time (SSRT)--provides a well-established paradigm for measuring response inhibition. However, motivational influences on stop-signal performance and SSRT have not been examined. We conceptualize the stop-signal paradigm as a decision-making task involving the trade-off between fast responding and accurate inhibition. In 4 experiments, we demonstrate that performance trade-offs are influenced by inherent motivational biases and explicit strategic control. As a result, SSRT was lower when participants favored correct stopping over fast responding than when the same participants favored fast responding over correct stopping. We present a novel variant of the stop-signal task that uses monetary incentives to manipulate motivated speed-accuracy trade-offs. By sampling performance at multiple-trade-off settings, we obtain a measure of inhibitory ability that is independent of trade-off bias, and thus, more easily interpretable when comparing across participants. We present a working theoretical model to explain the effects of motivational context on response inhibition.