This article describes a quantitative model, which suggests what the underl
ying mechanisms of cognitive control in a particular task-switching paradig
m are, with relevance to task-switching performance in general. It is sugge
sted that participants dynamically control response accuracy by selective a
ttention, in the particular paradigm being used, by controlling stimulus re
presentation. They are less efficient in dynamically controlling response r
epresentation. The model fits reasonably well the pattern of reaction time
results concerning task switching, congruency, cue-target interval and resp
onse-repetition in a mixed task condition, as well as the differences betwe
en mixed task and pure task conditions.