Psychology ETDs

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A model of foreperiod effects in simple reaction time, based on Variable Criterion Theory, was proposed. In this model foreperiod varied within session affects the mean of the distribution of the response criterion in accord with the changing conditional probability of imperative signal occurrence. Increases in between-session foreperiod are hypothesized to increase the variability of the criterion because of errors in time estimation. These assumed criterion effects predict the existing empirical foreperiod effects if the growth of sensory strength is a negatively accelerated function of time. The results of Experiment 1 indicate that the mean of the criterion decreases with longer within-session foreperiod as hypothesized. However, the between-session foreperiod effect appears to be due to increased overall criterion with longer foreperiod rather than to changes in the criterion variability. Experiment 2 produced results in mean reaction time that were consistent with the conclusions of Experiment 1 but which were difficult to interpret using the traditional stage model approach. While not rejecting alternative models, this study establishes that Variable Criterion Theory can provide a reasonable explanation of foreperiod effects.

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First Committee Member (Chair)

G. Robert Grice

Second Committee Member

Thomas Patrick Friden

Third Committee Member

Carol Elizabeth Conrad

Fourth Committee Member

John Marshall Rhodes



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Psychology Commons