In experimental psychology, backward inhibition, is a theory of sequential task control asserting that switching between tasks requires the just-completed task to be suppressed to allow a new task to be completed. Support for 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. This typically comes in an ABA format, with the response time of task A the second time taking longer after having completed task B. Backward inhibition is not seen in scenarios with an ABC format, where no task is being repeated.