Hester Robert, Garavan Hugh
Trinity College, Dublin, Ireland.
Mem Cognit. 2005 Mar;33(2):221-33. doi: 10.3758/bf03195311.
In a series of three experiments, increasing working memory (WM) load was demonstrated to reduce the executive control of attention, measured via task-switching and inhibitory control paradigms. Uniquely, our paradigms allowed comparison of the ability to exert executive control when the stimulus was either part of the currently rehearsed memory set or an unrelated distractor item. The results demonstrated a content-specific effect-insofar as switching attention away from, or exerting inhibitory control over, items currently held in WM was especially difficult-compounded by increasing WM load. This finding supports the attentional control theory that active maintenance of competing task goals is critical to executive function and WM capacity; however, it also suggests that the increased salience provided to the contents of WM through active rehearsal exerts a content-specific influence on attentional control. These findings are discussed in relation to cue-induced ruminations, where active rehearsal of evocative information (e.g., negative thoughts in depression or drug-related thoughts in addiction) in WM typically results from environmental cuing. The present study has demonstrated that when information currently maintained in WM is reencountered, it is harder to exert executive control over it. The difficulty with suppressing the processing of these stimuli presumably reinforces the maintenance of these items in WM, due to the greater level of attention they are afforded, and may help to explain how the cue-induced craving/rumination cycle is perpetuated.
在一系列三个实验中，研究表明增加工作记忆（WM）负荷会降低注意力的执行控制，这是通过任务切换和抑制控制范式来衡量的。独特的是，我们的范式允许比较当刺激是当前复述的记忆集的一部分或无关的干扰项时施加执行控制的能力。结果表明了一种内容特异性效应——就将注意力从当前保存在工作记忆中的项目上转移开或对其施加抑制控制而言，特别困难——随着工作记忆负荷的增加而加剧。这一发现支持了注意力控制理论，即积极维持相互竞争的任务目标对执行功能和工作记忆容量至关重要；然而，这也表明通过积极复述赋予工作记忆内容的更高显著性对注意力控制产生了内容特异性影响。这些发现与线索诱发的沉思有关，其中工作记忆中对唤起性信息（例如，抑郁症中的消极想法或成瘾中的与药物相关的想法）的积极复述通常是由环境线索引起的。本研究表明，当再次遇到当前保存在工作记忆中的信息时，对其施加执行控制会更加困难。抑制这些刺激处理的困难可能会加强这些项目在工作记忆中的维持，因为它们得到了更高程度的关注，并且可能有助于解释线索诱发的渴望/沉思循环是如何持续的。
