The salience of the stop signal affects triggering and latency of response inhibition across species: findings from a Bayesian approach

Abstract

The visual salience of a stop signal influences inhibitory performance. In Stop Signal Task, increasing stop signal salience decreases the latency of the inhibitory process (Stop Signal Reaction Time, SSRT). However, traditional SSRT estimation methods do not account for trigger failures, cases in which the inhibitory process is not triggered, leading to distorted SSRT estimates. Consequently, an effect on SSRT may reflect changes in the speed of inhibitory process or differences in its triggering. It therefore remains unclear whether stop signal salience affects speed or triggering of the inhibitory process. To address this issue, we reanalyzed behavioural data from human and macaque studies in which stop signal salience was manipulated, using an SSRT method that accounts for trigger failures and quantifies their occurrence. Our results show that higher stop signal salience shortens SSRT and reduces the probability of trigger failure. The same effects were present in single monkey sessions. These findings highlight the importance of detection for response inhibition. Since these effects were observed in both humans and rhesus macaques, they provide preliminary support for similarities in inhibitory control across species.