Brown, A. L. & Compione, J. C. (1972). Recognition memory for perceptually similar pictures in preschool children. Journal of Experimental Psychology, 95(1), 55-62.

A continuous recognition memory task was employed in three experiments with preschool children. On test trials, the stimuli were from one of three categories, new, old-identical, or old-similar. The latter category consisted of pictures of a character seen previously (hence old) but now shown in a similar, but different, pose. Exerpiment I investigated short-term (within a session) retention, and Exp. II and III investigated retention over longer periods (up to 7 days). In general, the data from Exp. I and III indicated that Ss were able to discriminate identical and similar recurrences of a central character even up to a 7-day retention interval, demonstrating that considerable detail of the original picture was both stored initially and retained for an extended period. In Exp. II, Ss consistently responded correctly on old-similar items but made more errors on old-identical items, with this difference increasing with longer retention intervals. This divergence was attributed to a response bias; i.e., with increasing retention interval, Ss' tendency to respond SIMILAR rather than IDENTICAL increased. The results obtained in Exp. III supported this interpretation.