Running Head: PERCEPTION AND MEMORY 1 Tracking Performance at the Crossroads of Perception and Memory

One of the most robust effects in memory is the spacing effect--memory is improved for repeated stimuli separated by intervening items (spaced encoding) relative to immediate stimulus repetitions (massed encoding). Because there are individual differences in working memory capacity (the number of items a person is able to attend to simultaneously) we sought to define the relationship between the spacing effect and working memory. We worked under the hypothesis that the spacing effect works through a mechanism known as repetition attenuation— this is a reduction in processing for repeated items. When other items intervene in between repetitions, the amount of processing approaches baseline as a function of spacing. Studies have shown that as the combined amount of processing for the item presentations during the test phase increases, recognition memory improves. To test the theory that the spacing effect is due to differences in perceptual processing of repeated items, we designed a novel experiment that includes three spaced conditions and a massed condition. Famous and unfamiliar human faces were used as stimuli. We administered a measure of working memory capacity called the “Ospan ” (operation span), and we predicted a direct relationship between o-span and memory performance, such that individuals with larger working memory capacities would show the greatest memory performance in the ‘long ’ spacing condition. We found significant main effects of spacing and stimulus familiarity for recognition performance and study phase priming, which is a correlate of repetition attenuation