Peripheral cues matching a searched-for target feature are known to capture attention, lending support to the notion, that human visual attention is primarily driven by top-down factors. However, recently side conditions, in which also top-down non-matching cues captured attention, were reported. More specifically, under some circumstances, inconsistently colored non-matching cues captured attention. This is in stark contrast to the aforementioned theory of top-down guided visual attention. In the present research, we investigated the role of perceptual and cognitive load that may have also exerted an influence on these previous findings. To that end, we independently manipulated the amount of perceptual and cognitive load by way of digits and symbols (Mongolian letters) embedded within the cues, as well as by adding a memory task in between searches. We found that perceptual load decreased capture by top-down non-matching cues and that increased cognitive load increased capture by top-down non-matching cues. Taken together, our results suggest that interspersing memory tasks with search tasks increases cognitive load to that point that even top-down non-matching cues capture attention.
Mott et al. (Fri,) studied this question.