Figure 1.

(A) Memory displays used in the WM filtering task in Experiment 1–3. The left column shows memory displays in which targets are presented laterally and distractors are presented on the vertical midline. These trials allowed to isolate target-related processing and extract target-elicited lateralized ERP components (N2pc, CDA). The right column shows memory displays in which distractors are presented laterally and targets are presented on the vertical midline. These trials allowed to isolate distractor-related processing and extract distractor-elicited lateralized ERP components (early PD, PD, CDAp). In Experiment 1, two targets were presented together with two or four distractors. In Experiment 2, in addition, six distractor could be presented. In Experiment 3, two targets and four distractors were presented in each trial; the distractor could be homogeneous or heterogeneous. (B) Shows a trial sequence. Each trial started with a fixation cross that was followed by the memory display. Subsequently an empty screen (with just placeholders) was presented before a probe appeared at one of the previous target locations. Participants had to decide whether the probe had the same color as the target previously presented at the same location.