Time versus items in judgment of recency.

In the numerical judgment of recency (JOR) task, subjects judge how many items have intervened since the test item was previously presented. Two experiments were conducted to determine whether the basis of JOR is the age of the memory (time) or the number of intervening items. Subjects went through a long list that was made up of alternating fast blocks and slow blocks, but the block structure was disguised by probabilistic selection of a short or long intertrial interval. In both experiments, JOR was found to be a simple function of time, with no added contribution from the number of items.