The stop-signal paradigm

Response inhibition—the ability to stop responses that are no longer appropriate—is frequently studied with the stop‐signal paradigm. In the stop‐signal paradigm, participants perform a choice response time task that is occasionally interrupted by a stop signal. The stop signal prompts participants to withhold their response on that trial. Performance in the stop‐signal paradigm is typically formalized as a horse race between a go and a stop process. If the go process wins the race, the response in executed; if the stop process wins the race, the response is inhibited. The stop‐signal paradigm owes its popularity to the underlying horse‐race model that enables researchers to estimate the latency of the unobservable stop response. In this chapter, we present a theoretical review of the stop‐signal paradigm and the corresponding horse‐race model. First we focus on the standard independent horse‐race model and discuss the most important measures of inhibitory control in the stop‐signal paradigm. We then describe the latest developments in the model‐based analysis of stop‐signal data. We conclude the chapter with recommendations on how to run stop‐signal experiments and how to report and interpret the results of stop‐signal studies.