Attentional capture refers to the phenomenon that task-related stimuli unconsciously capture attention and get priority processing in attentional orientation. Attentional control Settings (ACS) can guide attention to task-related stimuli, and then preferentially process it. When target is defined as a category composed of multiple objects, the attention system will form category-specific attentional control settings (cACS). Investigating the mechanism of cACS in attentional capture can not only expand and enrich previous theoretical research, but also provide basis and guidance for real life.
The present study reviewed the characteristics of cACS. Firstly, related to the processing stage of cACS, some previous studies claimed it occurred at an early stage, while others thought it happened at a late stage. Two-stage hypothesis combined these two views and postulated that different cACS can guide attention independently at the early stage, and then integrate into one single cACS at the late stage. In addition, cACS can also be preactivated in the preattentive stage to improve the subsequent search efficiently.
Secondly, relative to the processing weight of cACS, the attributes (e.g., color, size, shape or motion) of category, the size of items in category and the abstraction of categorical hierarchy were proven to be the impact factors of the processing weight of cACS. Specifically, the processing weight of cACS was lower than the feature-specific attentional control settings (fACS). The weight of color-specific cACS was larger than that of other cACSs. The weight of cACS was reduced along with a larger size of items in category. And the weight of superordinate-level cACS was lower than that of subordinate-level cACS.
Thirdly, relative to the involved brain regions of cACS, we summarized the previous functional brain imaging research and found object-selective cortex (OSC) involved the processing of extracting cACS stored in long-term memory and selecting target/inhibiting distractor.
Finally, we summarized the neural mechanisms of cACS in attentional capture. Firstly, cACS can preactivate in the early preattentive stage of processing to promote the detection of categorical stimuli (as the involvement of OSC). When the visual stimulus is occurred, cACS can compare the current stimulus to the definition of target (as the index of N1 and P1 components), the frontal parietal network (PFC, LIP, etc.) involve in the category judgment process, and the left superior temporal sulcus (lSTS) participate in the integration of top-down and bottom-up processing. The stimulus that matches target definition can induce attentional capture (as the index of N2pc component), while the stimulus that mismatches the target definition can elicit attentional inhibition (as the index of PD component). When cACS engage in visual search task, the processing weight of attention is affected by different attributes (color, shape, etc.), item size within category, category hierarchy. In addition, if the target is defined as multiple cACS (e.g., a digit with warm color), the different dimensions of cACS (e.g., symbol and color ) will affect attentional capture independently at the early stage, and then these two independent cACS can be integrated into one cACS in the late stage. In the late stage, the consolidation in working memory (as the index of CDA component) and the behavioral response (as the index of accuracy and response time and the involvement of SMA and precuneus) are involved.
Future studies can focus on the categorical rejection template for distractors, the various effects of different types of cACS in attentional capture, and the mechanism of artificial cACS.