Figure 1.

Task design. During List 1, subjects studied individual objects (e.g., bench, apple). During List 2, subjects saw novel objects that were from the same categories as the objects shown in List 1 (e.g., a new bench, a new apple). Preceding each List 2 object was an OLD instruction cue or NEW instruction cue. The OLD cue signaled that subjects were to retrieve the corresponding object from List 1 (e.g., the old apple). The NEW cue signaled that subjects were to encode the current object (e.g., the new bench). Each run of the experiment contained a List 1 and List 2; object categories (e.g., bench) were not repeated across runs. List 1 and List 2 objects separated by <18 intervening objects were coded as near, and List 1 and List 2 objects separated by ≥18 intervening objects were coded as far (see Materials and Methods). Lines around the boxes are shown for illustrative purposes and were not present during the actual experiment. After eight runs, subjects completed a two-alternative forced-choice recognition test that tested memory for each List 1 and List 2 object. On each trial, a previously presented object, either from List 1 or List 2, was shown alongside a novel lure from the same category. The subject's task was to choose the previously presented object. List 1 and List 2 objects were never presented together.