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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., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Titchener's (1908) law of prior entry states that "the object of attention comes to consciousness more quickly than the objects which we are not attending to," or otherwise, that attended stimuli are perceived earlier than unattended stimuli. Shore, Spence, and Klein (Psychological Science, 12, 205-212. doi: 10.1111/1467-9280.00337 , 2001) showed that endogenous visuospatial orienting does in fact elicit prior-entry effects, albeit to a smaller degree than does exogenous visuospatial orienting. In disagreement with this finding, Schneider and Bavelier (Cognitive Psychology, 47, 333-366. doi: 10.1016/S0010-0285(03)00035-5 , 2003) found no effect of their instruction to attend. They concluded that nonattentional effects could masquerade as prior entry, which could account for findings such as those in Shore et al.'s endogenous condition. We investigated this empirical and theoretical discord by replicating the temporal-order judgment task used by Shore, Spence, and Klein, while manipulating and measuring endogenous orienting by way of an orthogonal color probe task. We showed evidence of prior entry as a consequence of endogenous orienting, supporting the conclusions of Shore, Spence, and Klein.

People shift their attention in the direction of another person's gaze.This phenomenon, called gaze cuing, shares properties with purely endogenous (i.e., "deliberate") and purely exogenous (i.e., "reflexive") control of spatial attention. For example, as with purely endogenous orienting, gaze cues appear at visual fixation; yet, as with purely exogenous orienting, gaze cues elicit shifts of attention rapidly after their appearance. Prior experiments have shown that when controlled endogenously versus exogenously, the effects of attention upon the processing of targets are dramatically different. Briand and Klein (1987; see also Briand, 1998) showed that endogenous orienting is additive with opportunities for illusory conjunctions, whereas exogenous orienting is interactive. Klein (1994) showed that endogenous orienting is interactive with nonspatial expectancies,whereas exogenous orienting is additive. In the present project, we applied this double-dissociation strategy to attention controlled by gaze cues. In Experiment 1, gaze cuing effects (in accuracy) were additive with opportunities for illusory conjunctions (akin to endogenous control), whereas in Experiment 2, gaze cuing was additive with the nonspatial expectancy effect (akin to exogenous orienting). Therefore, in the nature of its effects upon performance, gaze cuing functions like a hybrid of endogenous and exogenous orienting. [ABSTRACT FROM AUTHOR]

Chen, X., Chen, Q., Gao, D. & Yue, Z. (2012). Interaction between endogenous and exogenous orienting in crossmodal attention. Scandinavian Journal of Psychology 53, 303-308. Using a cue-target paradigm, we investigated the interaction between endogenous and exogenous orienting in cross-modal attention. A peripheral (exogenous) cue was presented after a central (endogenous) cue with a variable time interval. The endogenous and exogenous cues were presented in one sensory modality (auditory in Experiment 1 and visual in Experiment 2) whereas the target was presented in another modality. Both experiments showed a significant endogenous cuing effect (longer reaction times in the invalid condition than in the valid condition). However, exogenous cuing produced a facilitatory effect in both experiments in response to the target when endogenous cuing was valid, but it elicited a facilitatory effect in Experiment 1 and an inhibitory effect in Experiment 2 when endogenous cuing was invalid. These findings indicate that endogenous and exogenous cuing can co-operate in orienting attention to the crossmodal target. Moreover, the interaction between endogenous and exogenous orienting of attention is modulated by the modality between the cue and the target. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Studies on brain computer interfaces (BCIs) have been mainly concerned with algorithm improvement for better signal classification. Fewer studies, however, have addressed to date the role of cognitive mechanisms underlying the elicitation of brain-signals in BCIs. We tested the effect of visuospatial attention orienting on a P300-guided BCI, by comparing the effectiveness of three visual interfaces, which elicited different modalities of visuospatial attention orienting (exogenous vs. endogenous). Methods: Twelve healthy participants performed 20 sessions, using the abovementioned P300-guided BCI interfaces to control a cursor. Brain waves were recorded on each trial and were subsequently classified on-line using an ad hoc algorithm. Each time the P300 was correctly classified, the cursor moved towards the target position. Results: The “endogenous” interface was associated with significantly higher performance than the other two interfaces during the testing sessions, but not in the follow-up sessions. Conclusions: Endogenous visuospatial attention orienting can be effectively implemented to increase the performance of P300-guided BCIs. Significance: The study of visuospatial attention underlying participants’ performance is essential for implementing efficient visual BCIs. [Copyright &y& Elsevier]