Abstract
Perceptual representations fade rapidly unless transformed into durable working memory representations. This transformation process, called short-term consolidation, can be measured in change-detection tasks by using a mask at various times following the sample array to disrupt the perceptual representation before it has been consolidated (Vogel, Woodman, & Luck, in press). In this present study, we asked whether consolidation is (a) a continuous process that gradually produces a more and more precise representation, or (b) a discrete process in which the representation is lost unless it has reached a particular level of activation. To address this question, we developed a color recall task in which it is possible to independently estimate the probability that a representation was formed and, if so, the precision of this representation. We found that, as the amount of time between the sample and the mask array increased, the probability that an item was consolidated increased. However, increasing the time available for consolidation did not influence the precision of the working memory representation. These results are consistent with a model in which the activation level of a working memory representation must reach a threshold before the perceptual representation is masked in order to survive; if the working memory representation does not reach the threshold, it is lost entirely.
This research was made possible by grants R01 MH63001 and R01 MH076226 from the National Institute of Mental Health.