This paper argues that the hippocampus is involved in mnemonic processes by virtue of being necessary to the execution of conditional operations occurring during the retrieval of acquired information from memory. A series of experiments indicating that animals suffering from hippocampal dysfunction are incapable of behaving conditionally in learning situations is described. Other effects of hippocampal dysfunction are then explained in terms of disruption of conditional retrieval processes. The paper continues by defining retrieval as the selection of one piece of information from among many possible candidates. It is argued that such a process is of little utility in basic associative theories, as associative processes result in one predominant memory for any given stimulus. Cognitive theories, in contrast, have held that many things may be known about a given stimulus and thus selection among memories is mandatory. The process of conditional retrieval is then defined as the result of interaction between a categorical operator, representing global factors, and a local operator, representing local considerations. Interaction between these two types of operators is shown to be necessary for constructing dimensional representation, including maps. To hold that the hippocampus is involved in the construction of dimensional representations in general affords an opportunity to begin relating cognitive processes to physiological knowledge and to answer some of the broad conflicts between associative and cognitive theories of learning. It is further suggested that studies of hippocampal development may shed light on cognitive development.Studies on the function of brain structures in producing behavior must be done within some sort of psychological framework; otherwise the results cannot be interpreted. The capability of the framework in interpreting the results is, in turn, an indicator of the validity of the framework. Thus, studies of the behavioral function of structures deal not only with neurological mechanisms, but also with psychological processes. Studies of the role of the hippocampus in producing behavior have something quite important to say about the nature of learning and memory and, very possibly, about cognitive development.
Memory