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

Abstract

The stop-signal task is widely used in experimental psychology and cognitive neuroscience research, as well as neuropsychological and clinical practice for assessing response inhibition. The task requires participants to make speeded responses on a majority of trials, but to inhibit responses when a stop signal appears after the imperative cue. The stop-signal delay after the onset of the imperative cue determines how difficult it is to cancel an initiated action. The delay is typically staircased to maintain a 50% stopping accuracy for an estimation of stopping speed to be calculated. However, the validity of this estimation is compromised when participants engage in strategic slowing, motivated by a desire to avoid stopping failures. We hypothesized that maintaining stopping accuracy at 66.67% reduces this bias, and that slowing may also be impacted by the level of experimenter supervision. We found that compared with 50%, using a 66.67% stopping accuracy staircase produced slower stop-signal reaction time estimations (≈7 ms), but resulted in fewer strategic slowing exclusions. Additionally, both staircase procedures had similar within-experiment test–retest reliability. We also found that while individual and group testing in a laboratory setting produced similar estimations of stopping speed, participants tested online produced slower estimates. Our findings indicate that maintaining stopping accuracy at 66.67% is a reliable method for estimating stopping speed and can have benefits over the standard 50% staircase procedure. Further, our results show that care should be taken when comparing between experiments using different staircases or conducted in different testing environments.

Faster action reprogramming, but not stopping, with proactive cues: Combining EMG and computational modelling in response-selective stop signal tasks

“…Note that, in theory, the censoring effect on both the lower and upper ends of the distribution could result in either up-or down-bias in stop estimates, depending on which effect is stronger. This censoring may be reduced by adopting strategies that maximise the proportion of stop trials with a partial burst, including (i) the use of stiff buttons 15,31 , which require more force (and time) to register a response; or (ii) task designs that minimise delays in go-RT, which would favour fast responses during stop trials and avoid a strategy of waiting for the stop signal before responding, such as modifying SSD staircasing to increase stopping success rates and reduce strategic slowing 58 . In conclusion, EMG CancelTime can be a valuable complementary measure to understand the underlying mechanisms involved in motor inhibition despite its limitations.…”