Endogenous cueing effects for detection can be accounted for by a decision model of selective attention

Spatial attention modulates multisensory integration: The dissociation between exogenous and endogenous orienting

Previous studies have separately found that exogenous orienting decreases multisensory integration (MSI), while endogenous orienting enhances MSI. It is currently unclear, however, why the two orientations have opposite effects on MSI. In the current study, we investigated the interaction between spatial attention and MSI in two experiments based on the cue-target paradigm. Experiment 1 separated exogenous and endogenous orienting to investigate the effect of spatial attention on MSI by varying the predictability of the cue. Experiment 2 further explored the effect of endogenous orienting on MSI. We found that exogenous orienting induced by the directionality of the cue decreased MSI, while endogenous orienting induced by the predictability of the cue enhanced MSI. The role of spatial orienting need and spatial attention bias in the modulation of MSI by exogenous and endogenous orienting was discussed. The present study sheds new light on how spatial attention modulates MSI processes.

Evidence from partially valid cueing that words are processed serially

There has been a longstanding debate about whether lexical and semantic processing of words is serial or parallel. We addressed this debate using partially valid cueing, where one of two words is cued. The cue was valid on 80% and invalid on the other 20% of the trials. The task was semantic categorization, and performance was measured by accuracy. The new feature was to limit attentional switching using a postmask of consonants that closely followed the presentation of words. We found a large effect of cueing and, most importantly, performance for the uncued word was at chance. This chance performance was consistent with serial processing, but not with typical parallel processing. This result adds to the evidence from other recent studies that the lexical and semantic processing of words is serial.

Top-down knowledge surpasses selection history in influencing attentional guidance

Visual attention is influenced by the characteristics of the stimuli (bottom-up), their task relevance (top-down), and prior experience (e.g., selection history and learning). However, it is largely unclear how learning and selection history interact with top-down attentional guidance. We combined trial-and-error learning with a spatial cueing protocol to test whether previously learned target-defining features continued to capture attention if participants were instructed to search for a new target feature (Experiment 1) or had to learn a new target feature (Experiment 2). It turned out that the previously learned feature quickly stopped capturing attention when the target feature changed (Experiment 1; even before participants learned the new target-defining feature, in Experiment 2). Finally, in Experiment 3, in which participants learned to search for targets defined by two redundant features (color and orientation), we found possible reasons for the dominance of the instructed feature over learning. Participants reported using only the target color for their search. Consequently, only cues with a target color captured attention. The unused target orientation only captured attention in participants aware of both target-defining features (13 out of 23) and only if the orientation was presented in the target color. We conclude that knowledge of target-defining features and their use as search criterion is critical for attentional guidance, while previously learned target features either influence attentional guidance only contingent on such deliberately selected top-down based attentional control settings or may influence visual search but not attentional guidance.

Novel tests of capture by irrelevant abrupt onsets: No evidence for a mediating role of search task difficulty during color search

According to the attentional dwelling hypothesis, task-irrelevant abrupt-onset cues capture attention in a stimulus-driven way by eliciting spatial shifts and further dwelling at cue position until target onset. Consequently, search can be facilitated for targets at cued locations relative to uncued locations. Critically, effects of stimulus-driven capture can go undetected in mean reaction times and error rates when search is too easy. In contrast, according to the priority accumulation framework (PAF), cueing effects for task-irrelevant cues differ from cueing effects by task-relevant cues. Most critically, cueing effects by irrelevant cues do not necessarily index spatial shifts and more dwelling but rather retrieval of cueing information. We used both behavioral measures (i.e., cueing effects and distractor compatibility effects) and event-related potentials on direct visual orienting activity elicited by the cue (Experiment 2) as well as consequences on target processing (Experiment 1) to investigate whether task-irrelevant abrupt onsets elicited attention shifts and led to further dwelling. We found behavioral support for attentional effects of task-irrelevant cues, surprisingly, however, only when search displays remained on-screen until response. We found no support for the attentional dwelling hypothesis or for PAF in the size of cueing effects as a function of search difficulty. Critically, lateralized ERPs revealed that salience of abrupt onsets per se is not sufficient to elicit spatial shifts during color search. Finally, neurophysiological evidence demonstrates that choices toward the implementation of experimental protocols can dramatically alter behavioral results on attentional effects of salient, but task-irrelevant abrupt onsets and conclusions drawn from them.