Programming time as a function of response duration: a replication of "dit-dah" without possible guessing artifacts.

Reaction time was longer prior to longer-lasting pressing responses for low probability, unanticipated movements. By contrast, reaction time was independent of response duration for high probability, anticipated movements. This replicates and extends previous findings for choice and simple reaction time in the "dit-dah" paradigm. The present results (unanticipated responses) cannot be given a selective anticipation interpretation because the comparison is between responses which are never anticipated. The previous paradigm was open to an alternative interpretation in which selective anticipation of dit rather than dah could have produced the differences in choice reaction time. Confirmation of the finding that variations in required response duration lead to differences in reaction time supports the view that the underlying parameter of "complexity" in the "memory drum theory" may be response duration.