Conditional Response Probabilities Confirm Two Stages of Free Recall, Working Memory Very Localized, Second Stage Delocalized, Both with Strong Tendencies to Forward Subsequent Recalls

Abstract

Recently it was shown that free recall consists of two stages: the first few recalls empty working memory and a second stage concludes the recall (Tarnow, 2015; for a review of the theoretical prediction see Murdock, 1974). Here I investigate conditional response probabilities in Murdock's 40-1 (1962) free recall dataset. I find that the conditional response probabilities confirm the presence of two stages. The first stage is characterized by a large enhancement of the forward subsequent recall (up to 30 times chance) and a large suppression of backward recalls (up to 26 times smaller than chance for recalls between 10 and 40 items away). The second stage forward subsequent recall is enhanced by a factor of 5 and the probability of backward and forward recalls are concentrated at small distances. Thus both stages favor forward subsequent recalls. As in Tarnow (2015), the first stage is much more localized than the second stage. Working memory capacity is estimated in six ways to be about 4.5 word items for the 40-1 word list.