title: The development of automaticity in short-term memory search: Item-response learning and category learning.
abstract: In short-term-memory (STM)-search tasks, observers judge whether a test probe was present in a short list of study items. Here we investigated the long-term learning mechanisms that lead to the highly efficient STM-search performance observed under conditions of consistent-mapping (CM) training, in which targets and foils never switch roles across trials. In item-response learning, subjects learn long-term mappings between individual items and target versus foil responses. In category learning, subjects learn high-level codes corresponding to separate sets of items and learn to attach old versus new responses to these category codes. To distinguish between these 2 forms of learning, we tested subjects in categorized varied mapping (CV) conditions: There were 2 distinct categories of items, but the assignment of categories to target versus foil responses varied across trials. In cases involving arbitrary categories, CV performance closely resembled standard varied-mapping performance without categories and departed dramatically from CM performance, supporting the item-response-learning hypothesis. In cases involving prelearned categories, CV performance resembled CM performance, as long as there was sufficient practice or steps taken to reduce trial-to-trial category-switching costs. This pattern of results supports the category-coding hypothesis for sufficiently well-learned categories. Thus, item-response learning occurs rapidly and is used early in CM training; category learning is much slower but is eventually adopted and is used to increase the efficiency of search beyond that available from item-response learning. (PsycINFO Database Record
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University Bloomington.
authors.forename: Rui
authors.initials: R
authors.lastname: Cao
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University Bloomington.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Nosofsky
authors.affiliation: Department of Psychological and Brain Sciences, Indiana University Bloomington.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Shiffrin
mesh_terms: D032882:Comprehension / Q000502:physiology*; D005260:Female; D006801:Humans; D007858:Learning / Q000502:physiology*; D008297:Male; D008433:Mathematics; D008570:Memory, Short-Term / Q000502:physiology*; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D021641:Recognition, Psychology / Q000502:physiology*; D012858:Size Perception / Q000502:physiology*; D013334:Students; D014495:Universities