On the consistency of tapping to repeated noise.

Repeated noise at 1-4 cycles per second evokes an effortless heard rhythmic sensation which is often heard as "clanks" and "rasping." Tapping in synchrony with the period of the perceived structure is easy and consistent within one presentation. The present study addresses the question of whether the tapping to presentations at different times is consistent across presentations and across subjects. Nine listeners from three countries were presented with repeated Gaussian noise samples in 300 separate cyclical presentations. Nine samples of Gaussian noise with sample lengths ranging from 500 to 700 ms were used. In each of the presentations, one of these samples was selected at random and presented cyclically with transientless juxtapositions. The listeners were instructed to tap in synchrony with the perceived structure (i.e., once per period). Tapping to later presentations of a given sample was found to be consistent with prior tapping to the same sample: In most cases, one or two different tapping points per noise sample could be reproduced in different presentations. In the case of two possible tapping points in different presentations, the two points are usually far away from each other (most likely half a period away). The correlation between subjects is noticeable, although not perfect. The correlation between subjects of the same country is not significantly higher. The noise generating algorithm is given explicitly to allow subsequent studies to use exactly the same noises.