Fig. 1. Schematic diagram of the working memory task.

During encoding, participants viewed three faces (cues) presented sequentially over 2.7 s. Upon the presentation of the third face, participants maintained either all three faces (high load, depicted in top row—i.e., arrows pointing outward) or the last face only (low load, depicted in bottom row—i.e., arrows pointing inward). After a jittered delay (D1) lasting 1.5, 3.5, or 5.5 s, subjects saw a distractor image for 2.5 s, during which time they made a button press to indicate whether the photograph showed a face or a place. After a second jittered delay (D2), subjects were presented with another face (decision) for 3 s, at which time they indicated whether they remembered it from the encoding period. A fixation cross was then displayed for the 1–7 s inter-trial interval (ITI) that preceded the next trial.