Abstract
When two tasks are performed at the same time increasing the demands of one of the tasks often increases interference in the other task. Surprisingly, it can also facilitate performance across tasks. For example, in the attentional boost effect memory for a picture is enhanced if it is encoded at the same time as an unrelated target square, rather than on its own or with a distractor square. This study tests whether across task facilitation effects depend on the continuous and simultaneous engagement of participants in both tasks. Participants encoded a continuous series of briefly presented pictures (500 ms per picture) into memory. A single colored square could appear in the center of each picture, and participants pressed a key whenever they detected a square in the target color. Participant’s engagement in the detection task was manipulated by presenting a square with each image (in a target or a distractor color; target+distractors), by omitting squares in distractor colors but not in the target color and presenting most pictures on their own (target-only), or by asking participants to ignore the squares (single-task encoding). Replicating the attentional boost effect, memory for pictures presented with a target was enhanced relative to those presented with a distractor. In contrast, in the target-only condition detecting a target interfered with memory for pictures that appeared within the next 1.5 s. Memory for pictures presented with targets was similar across conditions. These data indicate that target detection can offset dual-task interference costs even when stimuli for one task occur intermittently and unpredictably. However, engaging in two tasks at once does produce significant and long-lasting performance costs. These data are interpreted within the context of recent proposal that suggest that temporal selection is not task specific.
Meeting abstract presented at VSS 2015