An interruption paradigm was used to measure judgments that rely on cognitive extrapolation of approach and lateral motion. In some conditions the pattern of errors was consistent with that obtained with time-to-contact (TIC) judgments measured with a prediction motion (I'M) task. Also, the slope of the relationship between estimated and actual TTC in judgments of approaching objects decreased when visual information about the environment between the observer and the display was minimized. Moreover, the accuracy of relative duration judgments of visual (but not auditory) stimuli decreased when a PM task was performed concurrently. Results are consistent with the notion that PM tasks involve cognitive motion extrapolation rather than solely a clocking process that counts down TIC.

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