Sleep-Talking in Relation to Cognitive Psychology: Memory, Psycholinguistics, and Aphasia
The scientific literature dealing with wakeful cognition is intimidatingly huge. Until 1953, when the new electrographic sleep research era was inaugurated by Aserinsky, Kleitman, and Dement, cognition in sleep was by contrast unexplored; and even now, only the surface has been lightly touched. Most of the leading and influential ideas arose in clinical settings, and Freud's theories of dream formation and psychic structure dominated the field and have by no means lost much of their usefulness nor influence. As stated elsewhere ( Arkin, Antrobus, & Ellman, 1978a), the data base of theories of sleep cognition has been and will continue to be sleep mentation reports, including those of vivid dreams as a special subset. It naturally follows that sleep-utterance lends itself as both an independent and adjunctive source of empirical material to be included in such a data base. A study of the form, content, and correlates of sleep-utterance is rich territory. Three areas of cognitive psychology to which sleep-utterance seems relevant are the ontological status of sleep mentation, the study of memory mechanisms, and psycholinguistics, and we comment on some points of contact between them. But first we must deal with a fundamental issue -- in what senses may we say that when a person somniloquizes, he is in fact "talking in his sleep?"
It is necessary to state at once that a universally accepted unambiguous definition of sleep has not yet been formulated. Although polygraphic parameters, particularly those derived from the combined use of the EEG,