Activation of Semantic Memory

that the retrieval process consisted of at least two major steps: (a) entering the appropriate category and (b) finding the appropriate member of that category. Suppose now that we ask a subject to name a member of a category, and some time later ask him to name a different member of that category. Will the speed with which he retrieves the second instance depend at all on his having retrieved the first instance? Several recent lines of investigation suggest that producing an instance of a category will facilitate later production of another instance of that category. In one such investigation, Collins and Quillian (1970) presented sentences such as 'A canary is a bird' and required subjects to decide whether the sentences were true or false. Prior exposure to one sentence reduced reaction time to a second sentence, sometimes by as much as 600 msec, whenever the same subject noun was used. For example, prior exposure to 'A canary is a bird' reduced reaction time to other sentences about canaries.