ABSTRACT
During the past three decades of intensive research, many investigators have proposed their favorite version of hippocampal function. Indeed, so many theories have been propounded that it would be too lengthy and too tedious to list them all. Except for my own, no theory has proposed more than one function for the hippocampus. But as research reports have accumulated, new explanations of hippocampal function had to be found to accommodate the increasingly disparate results. Of necessity, these explanations became more and more general. The hippocampus was seen as generator of internal inhibition (Douglas, 1967, 1975), or as a mechanism for the suppression of interference from earlier memories (Isaacson, 1974; Weiskrantz & Warrington, 1975). Such a theory is so general that it explains everything and nothing. It explains everything—because every response could be explained by internal inhibition, which excludes all other responses. And every incorrect response could be explained as interference by earlier memories because learning depends on memory. Such a theory explains nothing—it does not explain the positive response choice that dictates the inhibition of other responses. It does not explain either positive or negative interference from earlier memories because it does not supply the trigger that suppresses undue or unwelcome interference.
