Hard-to-easy response inhibition reduces the perceived duration of fearful faces via associative learning

Concurrent execution of response inhibition and timing tasks can lead to bidirectional interference. However, it remains unclear how response inhibition toward specific stimuli influences subsequent time perception. To investigate this, we employed emotionally evocative facial stimuli (fearful faces) and manipulated the difficulty of response inhibition using reaction time deadlines (RTDs). In Experiment 1, participants performed a go/no-go task in which fearful faces were associated with go or no-go responses, followed by a temporal bisection task using the same faces. In Experiment 2, task difficulty was manipulated across two sessions, 1 week apart, by setting RTDs at 1,000 ms (Easy) and 500 ms (Hard). The association between fearful faces and response type was counterbalanced across participants. Results showed that fearful faces previously associated with no-go signals were judged to last for a shorter duration than those associated with go signals. In addition, during the second week, participants who completed the easy task first exhibited greater temporal underestimation compared to those who completed the difficult task first, while no significant difference was found during the first session. These findings are consistent with the idea that associative learning of response inhibition toward fearful faces can induce automatic inhibition, which, in turn, influences subsequent time perception. A stepwise reduction in response inhibition difficulty may serve as an effective strategy for modulating the subjective duration of negative emotional experiences.