Abrupt visual onsets and selective attention: Voluntary versus automatic allocation.

The hypothesis that abrupt visual onsets capture attention automatically, as suggested by Yantis and Jonides (1984) was tested in four experiments.A centrally located cue directed attention to one of several stimulus positions in preparation for the identification of a target letter embedded in an army of distractor letters.In all experiments, one stimulus (either the target or one of the distractors) had an abrupt onset; the remaining letters did not.The effectiveness of the cue was manipulated (varying either its duration or its predictive validity) to test whether abrupt onsets capture attention even when subjects are in a highly focused attentional state.Results showed that onsets do not necessarily capture attention in violation of an observer's intentions.A mechanism for partially automatic attentional capture by abrupt onset is proposed, and the diagnosticity of the intentionality criterion for automaticity is discussed.Introspective and empirical evidence both suggest that the abrupt appearance of an object in the visual field "draws attention."A plausible account of this phenomenon is that there exists a mechanism that is tuned to abrupt onsets and that one of its functions is to direct visual attention to the locus of an abrupt onset.This in turn could result in the efficient identification of information at that location.Another way of stating the hypothesis is that abrupt onsets may capture visual attention automatically and cause the observer to process abrupt visual events with high priority.This hypothesis has two components.The first is that there is a mechanism that detects abrupt onsets and signals the visual attention system to allocate attentional resources to events exhibiting abrupt onsets.The second is that the allocation of attention resulting from such a signal is automatic.We examine each of these components in turn.The central thesis of this article is that although attention may be efficiently allocated to abrupt onset under some circumstances, this may not happen in a truly automatic fashion, as defined by widely held criteria.The implication of this thesis is either that attentional capture by abrupt onset is not automatic or that one of the commonly cited criteria for automaticity is not really diagnostic of automaticity.