Backward inhibition is a theory of sequential task control that asserts switching between tasks requires the just-completed task to be suppressed to allow a new task to be completed. Support from the theory comes from research which has observed larger response times when returning to a task after an intermediate task than when completing three, or more, different tasks in a row. For example, for tasks A, B, and C the response times for the third task will be slower in the case of an A-B-A sequence than a C-B-A sequence. In a series of experiments it was shown that this inhibitory process is not the result of priming (Mayr & Keele, 2000).