How to disregard irrelevant stimulus dimensions: evidence from comparative visual search

To what extent is it possible to disregard stimulus dimensions that are irrelevant to a certain task? This question was tackled in three experiments using the paradigm of comparative visual search. Reaction times and eye-movement data were recorded in order to study the cognitive processes in this series of tasks. For the data analysis, task-specific variables were defined and their values computed across subjects and tasks. The results show that on the basis of top-down processes only, it is easier to ignore shape information, and that disregarding color information requires additional bottom-up processes.