Top-Down and Bottom-Up Control of Visual Selection: Controversies and Debate

T he amount of information available to the visual system is much greater than the amount we can fully process. Therefore, it is important that we select relevant information from the environment and ignore information that is irrelevant, particularly when this information may disrupt our actions. Selection implies that some objects or events are excluded from processing. This process of prioritizing information can be accomplished covertly or overtly (Posner, 1980).