Interruption from irrelevant auditory and visual onsets even when attention is in a focused state.

The common view on the interplay between exogenous and endogenous orienting holds that abrupt onsets are not capable of attracting attention when they occur outside the current focus of attention. Does this also apply to sudden irrelevant auditory onsets and when irrelevant visual onsets occur far in the periphery? In addition, does focused attention also reduce the alerting effect of auditory onsets, or vice versa, do highly alerting stimuli distort the attentional state? Crossmodal and unimodal variants of the Posner paradigm were examined in two experiments with targets and irrelevant onsets occurring at 28.3 and 19.3 degrees from fixation. Either centrally presented arrows indicated the forthcoming position of visual targets to be discriminated, or warning cues signaled the likely moment of target occurrence. The targets could be preceded by peripheral auditory or visual onsets that were to be ignored. Crossmodal and unimodal exogenous orienting effects of these irrelevant onsets were observed while participants focused at the relevant side. In addition, no evidence was found that the alerting effect of auditory onsets was dependent on focused attention. Our findings indicate that, at least under the current conditions, neither crossmodal nor unimodal orienting effects of peripheral events dissipate when attention is in a focused state.