High-Speed Scanning in Human Memory

and environments of the species; perhaps it would be most relevant for studying evolution of behavior. The second approach, however, enables systematic analysis of the influence of various environments and test situations on behavior of the species. The existence of interactions between variables does not imply that general statements cannot be made about genetic , age, or environmental factors per se. Significant main effects may still be the primary concern of the investigator and may frequently emerge. The value of such results increases considerably, however, if it is known that the effect occurs over a wide range of conditions and if the investigator is aware of specific interactions. How is symbolic information retrieved from recent memory? The study of short-term memory (1) has revealed some of the determinants of failures to remember, but has provided little insight into error-free performance and the retrieval processes that underlie it. One reason for the neglect of retrieval mechanisms may be the implicit assumption that a short time after several items have been memorized, they can be immediately and simultaneously available for expression in recall or in other responses, rather than having to be retrieved first. In another vocabulary (2), this is to assume the equivalence of the "span of immediate mem-ory" (the number of items that can be recalled without error) and the "mo-mentary capacity of consciousness" (the number of items immediately available). The experiments reported here (3) show that the assumption is unwarranted. Underlying the paradigm of these experiments is the supposition that if the selection of a response requires the use of information that is in memory, the latency of the response will reveal something about the process by which 652 References and Notes 1. 6. A longer, more detailed paper describing the complete study, including diallel cross and correlation analyses and a discussion of specific gamete, treatment, and sex effects is in preparation. Among previously undisturbed mice, mode of inheritance interacts with sex, and dominance appears within sexes. This finding is consist-ant with the results of J. H. Bruell: "Mode of inheritance of emotional defecation in mice," unpublished. E the information is retrieved. Of particular interest in the study of retrieval is the effect of the number of elements in memory on the response latency. The subject first memorizes a short series of symbols. He is then shown a test stimulus, and is required to decide whether or not it …