Speaker
Description
The human brain aligns actions to temporal regularities in sound, yet natural sounds often contain multiple competing onsets within a single event. How these landmarks are integrated to guide synchronized action remains unclear. We examined motor synchronization to competing acoustic onsets in speech and non-linguistic signals. Participants synchronized their tapping to consonant–vowel syllables in which the interval between burst and vowel onset varied systematically. As this interval increased, tap timing shifted toward the burst and became temporally more variable. This result indicates integration of both landmarks within a bound syllable but reduced stability. We then tested with non-linguistic stimuli in which a brief burst preceded a noise onset at varying distances. Increasing burst–noise distance continued to destabilize synchronization even when the burst no longer influenced tap timing. These findings reveal a dissociation between synchronization timing and stability, suggesting that while integration determines timing, competing but unbounded landmarks disrupt temporal precision.