A reaction-time adjusted PSI method for estimating performance in the stop-signal task

Abstract

A central experimental task in executive control research is the Stop-signal task, which allows measuring the ability to inhibit dominant responses. A crucial aspect of this task consists of varying the delay between the Go- and Stop-signal. Since the time necessary to administer the task can be long, a method of optimal delay choice was recently proposed: the PSI method. In a behavioral experiment, we show a variant of this method, the PSI marginal method, to be unable to deal with the Go-response slowing often observed in the Stop-signal task. We propose the PSI adjusted method, which is able to deal with this response slowing by correcting the estimation process for the current reaction time. In several sets of behavioral simulations, as well as another behavioral experiment, we document and compare the statistical properties of the PSI marginal method, our PSI adjusted method, and the traditional staircase method, both when reaction times are constant and when they are linearly increasing. The results show the PSI adjusted method’s performance to be comparable to the PSI marginal method in the case of constant Go-response times, and to outperform the PSI marginal method as well as the staircase methods when there is response slowing. The PSI adjusted method thus offers the possibility of efficient estimation of Stop-signal reaction times in the face of response slowing.

The effect of staircase stopping accuracy and testing environment on stop-signal reaction time

“…The exact method of SSD adjustment can vary across different versions of the SST. For example, some researchers have implemented a Bayesian staircase procedure that typically requires fewer trials to accurately estimate an individual's SSRT (Livesey & Livesey, 2016;Weise et al, 2018). However, the most common method of SSD adjustment is to simply increase or decrease the delay by a set numerical value (e.g., ± 50 ms) after each stop trial depending on the success of that trial.…”