Assessing working memory capacity through picture span and feature binding with visual-graphic symbols during a visual search task with typical children and adults.

This study investigated developmental memory capacity through picture span and feature binding. Participants included third grade students and college age adults with typical development. Picture span was used to assess working memory capacity when participants were asked to identify, locate, and sequence common visual-graphic symbols from experimental grid displays. Feature binding was assessed to evaluate how symbols, locations and sequences are bound together in working memory. The features assessed included symbol recall, location recall, symbol location binding, symbol sequence binding, and location sequence binding. All participants were shown a sequence of visual-graphic symbols on 4 by 4 stimulus grid displays. Participants were then asked to remember symbols amidst distractor symbols and place them in the correct location on a response grid, using the correct sequence. Results revealed expected developmental differences between third graders and adults on picture span. Significant differences between third graders and adults were also obtained for symbol sequence and location sequence binding. Performance for both groups on the sequence binding features were marginal (i.e., 30% of third graders and 60% of adults binding symbol sequence; 27% of third graders and 52% of adults binding location sequence). These results convey the influence of picture span and feature binding on working memory capacity. Implications are discussed in relation to theoretical models on working memory and compensatory strategies to increase feature binding with target and contextual memory.