The Effect of Stimulus Modality and Structure in Judging Seconds

Numerous studies have shown that when auditory and visual stimuli are presented with the identical objective durations, participants tend to perceive the auditory stimulus as lasting longer than the visual one. Moreover, auditory stimuli are estimated with less variability compared to visual stimuli. Additionally, the structure of the stimulus plays a significant role in shaping its subjective duration. Stimuli are judged to last longer when presented as a continuous signal (filled-interval) rather than as separate onsets and offsets (empty-interval; also known as the filled-duration illusion). One of the most commonly recognized intervals by humans is one second, the quantum of counting. People can remember one-second intervals and count based on them, even if they have not experienced them recently—an interval referred to as the long-term representation of one second (L1S), also known as chronometric counting. In this study, we explored how the modality and structure of stimuli affect the accuracy and precision of L1S. Our results revealed that auditory stimuli are judged significantly shorter than visual ones, which contradicts existing literature, yet showed that auditory stimuli have higher precision compared to visual stimuli, consistent with previous findings. We also found no significant effect of stimulus structure, as both filled and empty stimuli demonstrated comparable accuracy and precision. These findings emphasize the distinctive nature of counting seconds, which serve as a social reference point in human long-term memory.