Trace Theory of Perception for Temporal Bisection

Abstract The Trace Theory of Perception (TToP) is applied to temporal interval bisection. In this protocol, after familiarization with the referents for long or short judgments — the endpoints of the range — observers classify probe stimuli ‘short’ or ‘long’ (closer to the short or to the long referent). The midpoint of the range is predicted by TToP to be near and slightly above the geometric mean of the endpoints, and generally independent of signal modality. The observed bisection points, the time at which the probability of a long response is , deviates from those predictions. It was hypothesized that the deviations were caused by the observers’ bias to use categories equally often, which would be accomplished if the bisection point were at the median of the probes. A weighted average of the predicted midpoint and the median accounted for most of the variance in over 100 experiments, and explained the difference between linear and logarithmic spacing of probes.