Expectancy, attention, and time

Seven experiments examine the influence of contextual timing manipulations on prospective rime judgments. Subjects judged durations of standard vs com parison time intervals in the context of a preceding induction (context) se quence. In some experiments, the rate of the induction sequence was systema tically manipulated relative to the range of to-be-judged standard lime int ervals; in others, the induction sequence was omitted. Time judgments were strongly influenced by the rate of an induction sequence with best performa nce occurring when the standard time interval ended as expected, given cont ext rate. An expectancy profile, in the form of an inverted U, indicated th at time estimation accuracy declined systematically as a standard interval differed from a context rate. A similar expectancy profile emerged when the context rate was based on a harmonic subdivision lone-half) of an expected standard interval. Results are discussed in terms of various stimulus-base d models of prospective time judgments, including those which appeal to att entional periodicities and entrainment. (C) 2000 Academic Press.