TRADEOFFS BETWEEN ATTENTIONAL EFFECTS OF SPATIAL CUES AND ABRUPT ONSETS

We determined the relative effectiveness and tradeoffs among central, peripheral, and abrupt onset cues in directing attention to a potentia l target character. Central cues were arrows located at the fixation p oint, whereas peripheral cues were arrows occurring about 3-degrees aw ay from fixation, near the location of a potential target. These were contrasted with the abrupt onset of an ambiguous part of a character, which later was filled in to reveal a target or a distractor item. Eac h trial included an arrow cue and an abrupt onset cue, and both expect ed cue validities and cue-character SOAs were varied factorially. The results showed that, in general, abrupt onsets captured attention more effectively than either central or peripheral arrow cues. However, tr adeoffs among separate cue effects indicated that the power of abrupt onsets to capture attention automatically could be overridden by a hig h-validity spatial cue presented in advance of the onset character. Tr adeoffs between the effects of central and abrupt onset cues were addi tive, indicating that endogenous and exogenous cues have their main ef fects at different levels in the visual attention system. Peripheral c ues and abrupt onsets showed mainly interactive effects, however, cons istent with the idea that both types of cues have exogenous components that affect a common pool of attentional resources.