Free Recall Shows Similar Reactivation Behavior as Recognition & Cued   Recall
  I find that the total retrieval time in word free recall increases linearly with the total number of items recalled. Measured slopes, the time to retrieve an additional item, vary from 1.4-4.5 seconds per item depending upon presentation rate, subject age and whether there is a delay after list presentation or not. These times to retrieve an additional item obey a second linear relationship as a function of the recall probability averaged over the experiment, explicitly independent of subject age, presentation rate and whether there is a delay after the list presentation or not. This second linear relationship mimics the relationships in recognition and cued recall (Tarnow, 2008) which suggests that free recall retrieval uses the same reactivation mechanism as recognition or cued recall. Extrapolation limits the time to retrieve an additional item to a maximum of 7.2 seconds per item if the probability of recall is near 0%. Earlier upper limits for recognition and cued recall varied with the item type between 0.2 and 1.8 seconds per item (Tarnow, 2008). Implications include that there are only two types of short term memory: working memory and reactivation. 
Eugen Tarnow
q-bio.OT