The proposed research seeks to develop an operant test for implicit episodic memory, which is memory for unique, individually experienced events. A primary criterion of episodic memory is the binding together of information about What happened, Where it happened, and When it occurred (WWW memory) into an integrated memory trace. Experimental studies of episodic memory commonly use designs that depend on verbal reports of conscious memories in human subjects, and as a result, episodic memory is often considered an integral function of human consciousness. It is possible, however, that the formation of at least some episodic memories requires neither conscious recall nor verbal ability, that animals, pre-verbal children, or cognitively compromised adults may be able to make use of implicit memories of specific past occurrences that fit the primary diagnostic features of episodic memory. This possibility has important theoretical and practical implications. If subjects with cognitive deficits retain some unconscious memories of past events, this could modify our view of their cognitive capabilities of these populations and potentially lead to new forms of assessment in normal and at-risk populations. A determined search for criteria that do not depend upon verbal report is needed. One potentially valuable approach to this problem would be to develop such tests with nonhuman animal models. We propose to explore a range of novel experimental procedures employing operant techniques with California scrub jays, which have demonstrated impressive 'episodic-like'memory in a naturalistic context. The proposed experiments will test for integrated event memory, using designs that are more amenable to precise experimental control.
If any of these studies are successful in demonstrating episodic memory in scrub jays, the methodology can be readily applied to human subjects, providing significant benefits for the diagnosis and treatment of neuropsychiatric disorders, such as autism and schizophrenia. Development of a useable animal model of episodic memory will also permit further investigations of the underlying neurobiology, using pharmacological or neuroanatomical techniques that cannot be employed in human studies.
