Differential effects of auditory and visual signals on clock speed and temporal memory

The effects of signal modality on duration classification in college studen ts were studied with the duration bisection task When auditory and visual s ignals were presented in the same test session and shared common anchor dur ations, visual signals were classified as shorter than equivalent duration auditory signals. This occurred when auditory and visual signals were prese nted sequentially in the same test session and when presented simultaneousl y but asynchronously. Presentation of a single modality signal within a tes t session, or both modalities but with different anchor durations did not r esult in classification differences. The authors posit a model in which aud itory and visual signals drive an internal crock at different rates. The cl ock rate difference is due to an attentional effect on the mode switch and is revealed only when the memories for the short and long anchor durations consist of a mix of contributions from accumulations generated by both the fast auditory and slower visual clock rates. When this occurs auditory sign als seem longer than visual signals relative to the composite memory repres entation.