Discrimination of auditory temporal patterns

Two same-different discrimination experiments were performed for click patterns having a total duration of about 4 sec and interclick intervals of n x 250 msec, with n a random integer. In Experiment 1, the influence of the physical click group structure on discrimination performance was investigated. In Experiment 2, the effect of the strength of an induced internal clock on discrimination performance was measured. Performance was poor if the group structure of clicks was maintained during a change in click pattern and also if the induced internal clock strength was low. The performance of about 70% of the subjects improved significantly if either a change in click grouping structure occurred or a strong internal clock could be induced. These results cannot be accounted for with simple models based on single-interval duration discrimination or between-pattern correlation statistics.