不同搜索情境下老化对自上而下注意加工的影响

在视觉搜索过程中，老年人是否可以在不同情境下调节自上而下和自下而上的加工水平尚不明确。为了探讨老化对认知灵活性的影响，研究采用空间线索范式，通过比较有效线索和无效线索来考察对线索的注意加工水平（注意捕获、注意抑制），通过比较目标相关和目标无关线索的注意加工水平来考察自上而下和自下而上的作用，通过改变分心物一致性来调控不同的目标凸显情境。结果发现，年轻组在目标非凸显时的空间线索效应高于目标凸显时，表明年轻人会依据目标凸显性调整自上而下的加工水平；但老年组却没有产生这种差异，其更依赖自上而下的加工，注意系统会对目标相关的线索进行注意捕获，对目标无关的线索进行注意抑制。结果表明，随着年龄的增长，认知控制的灵活性下降，表现出对自上而下加工较多的依赖；此外，老年人依然保留着注意捕获和注意抑制的能力，这对认知老化中抑制能力受损的观点提出了挑战。

The Effects of Aging on Top-down Attentional Processing under Different Search Situations

In visual search, top-down and bottom-up processing can flexibly capture task-relative information and inhibit task-irrelative information according to different search situations. Specifically, the top-down processing can be enhanced when target is a salient stimulus among distractors, while the bottom-up processing can be enhanced when the target is not the salient stimulus. However, it is unclear that whether older people can adopt different attentional processing under different target situations as young people. In order to investigate the effects of aging on the flexibility of attention, the present study employed young and old people to participate a spatial cue target paradigm. Participants were instructed to search for a predefined color target and the target displays were preceded by spatially unpredicted color singleton cues. Color consistency of the distractors(consistent vs. inconsistent) was manipulated to change the salience situations of the target, Matching level of cue and target(task-relative vs. task-irrelative) was manipulated to investigate the top-down and bottom-up processing, Validity of cue(valid vs. invalid) was manipulated to measure the effects of attentional capture and inhibition. Results showed that, for young people, the effects of attentional capture for task-relative cues in salient situation was significantly smaller than that in the non-salient situation, suggesting that the young people can flexibly regulate the attentional processing according to different target situations. However, the result was disappeared for elders, indicating a lack of flexibility with aging. More importantly, the results of the IES(RT/ACC) showed a cue validity effect for the task-relative cue and a reversed cue validity effect for the task-irrelative cue in elder, indicating the remaining effects of attentional capture and inhibition of aging. In sum, the present study reveals that aging can decrease the flexibility of cognitive control, but still can retain the attentional capture for task-relative stimulus and the attentional inhibition for task-irrelative stimulus, which challenges the impaired inhibition ability of aging.