Components of task switching: A closer look at task switching and cue switching

Research using the diffusion model to decompose task-switching effects has contributed to a better understanding of the processes underlying the observed effect in the explicit task cueing paradigm: Previous findings could be reconciled with multiple component models of task switching or with an account on compound-cue retrieval/repetition priming. In the present study, we used two cues for each task in order to decompose task-switch and cue-switch effects. Response time data support previous findings that comparable parts of the switching effect can be attributed to cue-switching and task-switching. A diffusion model analysis of the data confirmed that non-decision time is increased and drift rates are decreased in unpredicted task-switches. Importantly, it was shown that non-decision time was selectively increased in task-switching trials but not in cue-switching trials. Results of the present study specifically support the notion of additional processes in task-switches and can be reconciled with broader multiple component accounts.     

The shielding function of task rules in the context of task switching

There is increasing evidence that task rules help shield the response against distractor interference. Here, the authors investigate the cognitive mechanisms underlying this assumed shielding function of task rules and how it is adjusted to changing task demands. In two experiments, participants switched between a noun categorization and an adjective categorization task. Target words were superimposed on distractor pictures. These pictures were always irrelevant and depicted either objects also used as target words in the noun task (noun distractors) or objects that were not part of the noun target-set but could be categorized according to the noun task (noun-related distractors). Results show that (a) on task repetitions shielding prevents interference from any distractors associated with a competing task; this is indicated by the lack of interference on adjective task repetitions; and (b) shielding is reduced on task switches. In the noun task, this reduction resulted in attenuated interference by noun-related distractors. In the adjective task, spatial distractors did not interfere despite the reduction. This result suggests that shielding is supported by a processing advantage for task-related information and not by distractor suppression.     

不同熟练程度藏汉双语者言语理解中的语码切换及其代价

以母语为藏语,第二语言为汉语的熟练和非熟练藏汉双语者为被试,采用词汇判断任务,在无切换、预期切换和无预期切换三种条件下,考察藏汉两种语言之间的语码切换及其切换代价。结果表明：（1）在三种条件下,熟练和非熟练藏汉双语者对汉语词的反应时均显著短于对藏语词的反应时,汉语词的错误率也显著低于藏语词;（2）切换条件下的反应速度显著慢于无切换条件,切换条件下的错误率显著高于无切换条件,存在显著的切换代价;（3）熟练藏汉双语者对汉语词的反应时显著短于非熟练藏汉双语者,熟练藏汉双语者对汉语词反应的错误率也显著低于非熟练藏汉双语者。本研究表明,藏汉双语语码切换过程中存在切换代价,支持抑制说;熟练藏汉双语者语码切换代价更小。     

任务切换中的反应重复效应

在任务重复试次中反应的重复对反应有促进作用,而在任务切换试次中反应的重复对反应有阻碍作用,此现象即为反应重复效应（response repetition effects, RRE）。RRE普遍存在不同任务切换范式中,是一种抽象反应编码重复效应,受刺激效价和一致性、反应编码重复度和准备时间等因素影响。其理论解释主要有重构论、启动-抑制论、以及情境检索说。现有研究初步表明前额叶皮层是RRE的关键脑区,但RRE的认知神经机制及理论解释还有待进一步探讨。