If at first you don’t succeed, try, try again: Second chances reveal more information in working memory

Working memory is thought to have a highly limited storage capacity, which constrains many cognitive abilities including fluid intelligence. Here we show that working memory is limited not only by storage capacity but also by failures to retrieve or make decisions about items that were successfully maintained. Participants memorized an array of circles and then reported a probed item’s color. Many responses were far from the true color, which is often interpreted as a failure to store the item. However, when participants were then given two choices and had to choose the correct color, performance was well above chance regardless of participants’ error on the first response. These results demonstrate an important role for retrieval and decision stages in working memory: sometimes items that are successfully stored are not successfully reported. Moreover, this data highlight that memory capacity is underestimated by traditional measures.