Interference and forgetting.

I know of no one who seriously maintains that interference among tasks is of no consequence in the production of forgetting. Whether forgetting is conceptualized at a strict psychological level or at a neural level (e.g., neural memory trace), some provision is made for interference to account for at least some of the measured forgetting. The many studies on retroactive inhibition are probably responsible for this general agreement that interference among tasks must produce a sizable proportion of forgetting. By introducing an interpolated interfering task very marked decrements in recall can be produced in a few minutes in the laboratory. But there is a second generalization which has resulted from these studies, namely, that most forgetting must be a function of the learning of tasks which interfere with that which has already been learned (19). Thus, if a single task is learned in the laboratory and retention measured after a week, the loss has been attributed to the interference from activities learned outside the laboratory during the week. It is this generalization with which I am concerned in the initial portions of this paper. Now, I cannot deny the data which show large amounts of forgetting produced by an interpolated list in a few minutes in the laboratory. Nor do I deny that this loss may be attributed to interference. But I will try to show 1 Address of the president, Midwestern Psychological Association, St. Louis, Missouri,