  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.
