Forgetting in an association memory

Though the phenomenon of forgetting is an everyday and commonplace experience of human intelligent systems it has been inadequately treated by theorists of intelligent systems (human and computer). On the one hand there is the stark behavioral fact that humans who were, at one point in time, able to respond in some particular way to some particular stimuli are, at a later time, no longer able to respond to those stimuli. On the other hand, there are the ever-intriguing experiences, shared by us all, that humans are able to recall stimuli whose age-in-memory is of the order of many years and that a person's technique of association can be pressed into the service of retrieving “long lost” information from his memory (sometimes quite consciously!) Furthermore, some modern experiments (4), involving the implantation and stimulation of microelectrodes in the brain, have suggested that experiences far removed in time can be evoked in great informational detail by appropriate stimulation of barin tissue.