Implicit and explicit memory in preschoolers
Creators: name: Buller, Terri
Publisher: name: University of British Columbia
Year: 2010

description: Explicit memory refers to conscious or deliberate recollection of recent events and experiences, whereas implicit memory is revealed when the same events and experiences affect performance in the absence of conscious recollection. It is well known that implicit and explicit memory develop differently across the life span: Explicit memory is acquired in early childhood, remains stable across adulthood, and then decreases in later life, whereas implicit memory develops earlier in childhood and remains intact well into late adulthood (for review see Graf, 1990). To explain this pattern of results, it has been suggested that implicit memory performance is mediated by automatic processing, whereas explicit memory performance is mediated by subject controlled processing, such as goals and strategies (e.g., Craik, 1983). My thesis examines whether development during the preschool years has the same effect or different effects on implicit and explicit memory test performance. Toward this goal, I first collected normative data to establish baserate performance on category production tests for use in the main experiment. Subjects consisted of 96 preschoolers and production norms were gathered for 7 different categories. The procedure involved reading a brief story to focus subjects attention on a category and required them to name 5 items from that category. Test performance showed two notable findings. First, some categories had a more gradual drop-off in response rate distributions than others, and second, differences in response rates for the different age groups were greater in some categories than others. The main part of this thesis is an experiment that examined whether development has the same effect or different effects on implicit and explicit memory test performance. Subjects for this study consisted of groups of 12 3-, 4-, and 5-year olds (n=36). The method involved presenting subjects with category production and category cued-recall tests for previously studied items. The items were selected from the norms according to three criteria: frequency of occurrence in the norms was not at floor or ceiling, occurrence frequencies were similar across age groups, and each item was representable as a picture. During the study phase five items were studied from each of 4 categories: CLOTHES, TRAVEL, PLAYGROUND, and ZOO. Ten of the 20 items (5 per category) were studied by each subject -- 5 in a non-elaborative study condition that required subjects to name each item and 5 in an elaborative study condition that asked them to name each item and answer a question about real-life aspects/uses of the item (e.g., "Do boys wear dresses?"). Two sets of target items that were not studied were used to assess baserate performance. The testing phase occurred immediately after the study phase. Implicit memory performance was assessed with category production tests using the same procedure as for the norms study. Explicit memory was assessed with a category cued-recall test. The critical findings from the implicit memory tests were: more priming in the elaborative than in the non-elaborative study conditions, and similarly large priming effects across age-groups. The explicit memory test results showed that performance increased across age-groups, but only for materials in the non-elaborative study condition. In the elaborative study condition 3-year olds' performance was comparable to that of the 5-year olds. The present thesis illustrated the distinction between implicit and explicit memory performance. Furthermore, it supports the hypothesis that while there is overlap of some of the components mediating these forms of memory, particularly related to storage of materials, there are significant differences between other mediating processes of implicit and explicit memory that are more closely associated with retrieval of materials.