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Abstract:
We are interested in the mechanisms by which individuals
monitor and adjust their performance of simple cognitive tasks.
We model a speeded discrimination task in which individuals are
asked to classify a sequence of stimuli (Jones & Braver,
2001). Response conflict arises when one stimulus class is
infrequent relative to another, resulting in more errors and
slower reaction times for the infrequent class. How do control
processes modulate behavior based on the relative class
frequencies? We explain performance from a rational perspective
that casts the goal of individuals as minimizing a cost that
depends both on error rate and reaction time. With two additional
assumptions of rationality -- that class prior probabilities are
accurately estimated and that inference is optimal subject to
limitations on rate of information transmission -- we obtain a
good fit to overall RT and error data, as well as trial-by-trial
variations in performance.
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