A rational analysis of cognitive control in a speeded discrimination task
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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