语言转换对非熟练双语者不同认知控制成分的即时影响

语言转换情境是否影响非熟练双语者的认知控制存在争议。实验1和实验2分别采用不同的实验范式探讨语言转换对非熟练双语者的认知控制是否会有即时的影响, 以及对不同认知控制成分的影响是否会有不同。结果表明, 语言转换情境能够即时地促进反应抑制, 阻碍干扰抑制, 但对认知灵活性没有影响, 同时说明了反应抑制、干扰抑制和认知灵活性属于3种不同的认知成分, 其内在作用机制不同。此外, 研究结果还进一步说明了双语者的认知控制优势是双语者长期双语使用的结果, 为双语优势的内在机制提供了实验支持。     

The roles of private speech and inner speech in planning during middle childhood: Evidence from a dual task paradigm

Children often talk themselves through their activities, producing private speech that is internalized to form inner speech. This study assessed the effect of articulatory suppression (which suppresses private and inner speech) on Tower of London performance in 7- to 10-year-olds, relative to performance in a control condition with a nonverbal secondary task. Experiment 1 showed no effect of articulatory suppression on performance with the standard Tower of London procedure; we interpret this in terms of a lack of planning in our sample. Experiment 2 used a modified procedure in which participants were forced to plan ahead. Performance in the articulatory suppression condition was lower than that in the control condition, consistent with a role for self-directed (private and inner) speech in planning. On problems of intermediate difficulty, participants producing more private speech in the control condition showed greater susceptibility to interference from articulatory suppression than their peers, suggesting that articulatory suppression interfered with performance by blocking self-directed (private and inner) speech.     

积极情绪对任务转换的影响

通过两个行为实验考察了积极情绪图片所诱发的情绪状态对任务转换的影响及其机制。研究任务是数字分类任务,分为保持和转换两个阶段。首先要求被试对靶刺激形成一定的习惯化反应,然后改变任务要求。实验1以53名大学生为被试,分别在积极情绪、消极情绪和中性条件下完成任务,发现在与中性条件相比时,积极情绪促进任务转换,消极情绪延缓任务转换。实验2以37名大学生为被试,增加了一种转换条件,考察积极情绪促进任务转换的心理原因,结果表明积极情绪因偏好新异刺激而促进任务转换     

The effects of recent practice on task switching

Four experiments investigated the effect of recent selective practice on the cost of switching between 2 tasks afforded by letter-digit pairs: alphabet arithmetic and shape comparison. Experiments 1 and 2 found a greater cost associated with switching to the more recently practiced task: evidence that task-set inertia contributes to switching costs. Experiment 3 found this effect to be limited to trials on which a recently trained stimulus followed another such stimulus: a result problematic for all current theories of task-set priming. Experiment 4 showed that the effect of recent practice was eliminated by active preparation for a task switch: It appears that endogenous task-set preparation reduces the effects of task-set inertia. ((c) 2003 APA, all rights reserved)     

Do children with autism use inner speech and visuospatial resources for the service of executive control? Evidence from suppression in dual tasks

Three experiments used dual‐task suppression methodology to study the use of inner speech and visuospatial resources for mediating central executive performance by children with autism (CWA) and group‐matched typically developing (TD) controls. Expt 1 revealed that CWA did not recruit inner speech to facilitate arithmetic task‐switching performance: there was no effect of articulatory suppression (AS) on completion time for CWA compared to the TD group. Expt 2 revealed that suppression of visuospatial resources disrupted the task‐switching performance of both CWA and TD groups. It also confirmed that the task‐switching performance of CWA was significantly slowed by visuospatial compared to AS. Expt 3 showed that CWA also did not employ inner speech, compared to visuospatial resources, for implementing planning movements. Overall, compared to the mixture of representations used by the TD group for problem solving, CWA seemed to use visuospatial working memory resources but not inner speech to service executive control.     

Inner speech as a retrieval aid for task goals: the effects of cue type and articulatory suppression in the random task cuing paradigm

Articulatory suppression has been shown to increase switch costs in the list paradigm (e.g., [J. Exp. Psychol.: General 130 (2001) 641, J Memory Language 48 (2003) 148]). The present dual-task study examined whether this effect generalizes to the random task cuing paradigm. Participants performed color or shape judgments according to explicit word cues (COLOR or SHAPE) or less transparent letter cues ( C for the color task and S for the shape task). In the word cue condition, the switch cost was equivalent for the articulatory suppression and the control (no dual-task) conditions, but, in the letter cue condition, the switch cost was significantly greater for the articulatory suppression condition than for the control condition. These results suggest that inner speech may be recruited as a tool for retrieving and activating the relevant task goal when the task cue is not transparent and hence imposes nonnegligible retrieval demand.     

On the role of verbalization during task set selection: Switching or serial order control?

Recent task-switching work in which paper-and-pencil administered single-task lists were compared with task-alternation lists has demonstrated large increases in task-switch costs with concurrent articulatory suppression (AS), implicating a crucial role for verbalization during switching (Baddeley, Chincotta, & Adlam, 2001; Emerson & Miyake, 2003). Experiment 1 replicated this result, using computerized assessment, albeit with much smaller effect sizes than in the original reports. In Experiment 2, AS interference was reduced when a sequential cue (spatial location) that indicated the current position in the sequence of task alternations was given. Finally, in Experiment 3, switch trials and no-switch trials were compared within a block of alternating runs of two tasks. Again, AS interference was obtained mainly when the endogenous sequencing demand was high, and it was comparable for no-switch and switch trials. These results suggest that verbalization may be critical for endogenous maintenance and updating of a sequential plan, rather than exclusively for the actual switching process.     

Becoming self-directed: Abstract representations support endogenous flexibility in children

A fundamental part of growing up is going beyond routines. Children become increasingly skilled over the first years of life at actively maintaining goals in the service of flexible behavior, allowing them to break out of habits and switch from one task to another. Their early successes often occur with exogenous (externally-provided) goals, and only later with endogenous (internally-driven) goals – a developmental progression that may reflect the greater demands on selection processes inherent in deciding what to do. Three studies investigated the mechanisms supporting endogenous flexibility, using a verbal fluency task in which children generated members of a category and could decide on their own when to switch from one subcategory to another. Children’s verbal fluency related to their performance in a more constrained and well-established switching task (Experiment 1), suggesting that the more complex verbal fluency measure taps the flexibility processes of interest. Children’s verbal fluency was also linked to their abstract, categorical representations in both individual difference analyses (Experiment 2) and experimental manipulation (Experiment 3). We interpret these results in terms of the role of abstract representations in reducing selection demands to aid the development of endogenous control.     

No-go trials can modulate switch cost by interfering with effects of task preparation

It has recently been shown that the cost associated with switching tasks is eliminated following ‘no-go’ trials, in which response selection is not completed, suggesting that the switch cost depends on response selection. However, no-go trials may also affect switch costs by interfering with the effects of task preparation that precede response selection. To test this hypothesis we evaluated switch costs following standard go trials with those following two types of non-response trials: no-go trials, for which a stimulus is presented that indicates no response should be made (Experiment 1); and cue-only trials in which no stimulus is presented following the task cue (Experiment 2). We hypothesized that eliminating no-go stimuli would reveal effects of task preparation on the switch cost in cue-only trials. We found no switch cost following no-go trials (Experiment 1), but a reliable switch cost in cue-only trials (i.e., when no-go stimuli were removed; Experiment 2). We conclude that no-go trials can modulate the switch cost, independent of their effect on response selection, by interfering with task preparation, and that the effects of task preparation on switch cost are more directly assessed by cue-only trials.     

Choosing to switch: Spontaneous task switching despite associated behavioral costs

The literature shows that switching among simple cognitive tasks is difficult and involves a performance cost. Accordingly, cost-benefit considerations seem to predict that task switching would not occur spontaneously. Here we show that spontaneous task switching is a robust phenomenon, despite its costs. In Experiment 1, participants had to judge shapes according to one of three possible dimensions. Importantly, they were given the option to choose another relevant dimension or let the computer program change the dimension for them, but only if they wanted to do so. The results showed that spontaneous task switching was prevalent, despite robust switching costs. Experiment 2 extended this finding in showing spontaneous switching from an easy task to a more difficult task. The authors provide two possible explanations for the phenomenon that posit that spontaneous switching may be unpreventable or even advantageous.     

Tasks of a feather flock together: Similarity effects in task switching

Recent research on task switching has paid little attention to how tasks are represented and how the relations between task representations might affect the executive processes engaged to achieve a task switch. Two experiments investigated the effect of task similarity on task switching. Similarity was defined in terms of shared component operations--attentional control settings in Experiment 1 and response modality in Experiment 2--with tasks sharing more component operations said to be more similar to each other than tasks sharing fewer component operations. Across both experiments, task similarity facilitated task switching, seen in reduced switch costs for switching between similar tasks as opposed to dissimilar tasks. These results indicate that task similarity defined in terms of component operations can be used to define a multidimensional task space in which the executive processes of task selection and implementation are active.     

The Switch Task for Children: Measuring mental flexibility in young children

Age-related changes in mental flexibility, in the form of task switching, were assessed in 292 children (58–156 months old). Task switching was examined with a new task for young children, the Switch Task for Children (STC). The STC consists of two easy, comparable games and does not require reading skills, which makes it suitable for children younger than 6 years of age. The aims of the present study were: (1) to evaluate the STC; (2) to examine task switching in young children; and (3) to study age-related changes in task switching across childhood. The results indicated that children younger than 6 years are able to switch between two tasks and that general performance increased with age. Young children (58–89 months) displayed a larger global switch cost, that is they made more errors when the tasks were presented randomly compared with a repeated-task baseline, than older children (106–156 months). These findings suggest that the STC is a useful task for detecting task-switching abilities in young children and that the ability to maintain and manipulate two different tasks in working memory, is present, but not yet fully developed, in young children.     

Inhibition of response mode in task switching

Task inhibition was explored in two experiments that employed a paradigm in which participants switched among three tasks. Two tasks required manual choice responses based on numerical judgment (parity or magnitude), whereas a third task required an unconditional double-press of both response keys. Both experiments showed that switching to a just-abandoned task (n-2 task repetition) generally leads to a performance cost relative to switching to another task. Specifically, this task inhibition effect also occurred for the double-press task, suggesting inhibition of response mode. Prolonging the task-cuing interval showed that advance task preparation reduced only inhibition of the double-press task but not of the choice tasks (Experiment 1). Prolonging the response-cue interval led to a decrease of the inhibition effect in all tasks (Experiment 2), suggesting a time-based release of task inhibition. Together, the experiments support the notion of a response-related component of task inhibition.     

Exploring task-set reconfiguration with random task sequences

Switching between two different tasks normally results in an impairment in people's performance known as a switch cost, typically measured as an increase in reaction time (RT) and errors compared to a situation in which no task switch is required. Researchers in task switching have suggested that this switch cost is the behavioural manifestation of the task set reconfiguration processes that are necessary to perform the upcoming task. However, an examination of the literature in task switching reveals apparently contradictory results about the nature of task set reconfiguration processes. In Experiment 1, we addressed this issue by comparing participants' performance in two different experimental conditions: predictable task switching and random task switching. In the predictable switch condition the switch cost completely vanished after the first repetition of the new task. However, in the random switch condition, while the difference between switch and repetition trials was not significant, we observed a significant reduction in RT between the first and second repetition of the new task. In Experiment 2, we further investigated the pattern of task set reconfiguration in the random switch situation. The results showed a progressive reduction of participants' response latencies across repetitions of the same task. The present study demonstrates that, whereas the results in predictable switching conditions are compatible with an exogenous-reconfiguration hypothesis, random task switching produces a more gradual, decay-like switch cost reduction with task repetition.     

The costs of crossing paths and switching tasks between audition and vision

Switching from one functional or cognitive operation to another is thought to rely on executive/control processes. The efficacy of these processes may depend on the extent of overlap between neural circuitry mediating the different tasks; more effective task preparation (and by extension smaller switch costs) is achieved when this overlap is small. We investigated the performance costs associated with switching tasks and/or switching sensory modalities. Participants discriminated either the identity or spatial location of objects that were presented either visually or acoustically. Switch costs between tasks were significantly smaller when the sensory modality of the task switched versus when it repeated. This was the case irrespective of whether the pre-trial cue informed participants only of the upcoming task, but not sensory modality (Experiment 1) or whether the pre-trial cue was informative about both the upcoming task and sensory modality (Experiment 2). In addition, in both experiments switch costs between the senses were positively correlated when the sensory modality of the task repeated across trials and not when it switched. The collective evidence supports the independence of control processes mediating task switching and modality switching and also the hypothesis that switch costs reflect competitive interference between neural circuits.     

Imagery and Recognition: Dissociable Measures of Memory?

An assumption of many theories of visual cognition is that imagery tasks and picture recognition tasks tap the same kind of memory processes (i.e. visual), implying that these two types of tests can be used as interchangeable measures of visual memory. In this paper, we investigated whether articulatory suppression—a variable known to improve imagery performance—has a similar effect on picture recognition performance. In Experiment 1, subjects performed either an imagery task or a recognition task while engaging or not in articulatory suppression; in Experiment 2, the same subjects performed first the imagery task, and then the recognition task, while engaging or not in articulatory suppression. When the type of task was manipulated between subjects (Experiment 1), imagery performance was significantly improved by articulatory suppression. In contrast, recognition performance was significantly impaired by the introduction of articulatory suppression. In accordance with results of Experiment 1, in Experiment 2 imagery and recognition performance were found to be unrelated. However, when the same subjects performed both tasks, the opposite effect of articulatory suppression on imagery vs recognition performance was observed only on the first item. It does appear that when the imagery task and the picture recognition task are performed in isolation, performance is found to be independent, suggesting that the two tasks are mediated by different mechanisms. However, when a within-subjects design is used, performance in one task can be contaminated by the presence of the other task.     

Delayed reconfiguration of a non-emotional task set through reactivation of an emotional task set in task switching: an ageing study

ABSTRACT

In our everyday life, we frequently switch between different tasks, a faculty that changes with age. However, it is still not understood how emotion impacts on age-related changes in task switching. Using faces with emotional and neutral expressions, Experiment 1 investigated younger (n?=?29; 18–38 years old) and older adults’ (n?=?32; 61–80 years old) ability to switch between an emotional and a non-emotional task (i.e. responding to the face's expression vs. age). In Experiment 2, younger and older adults also viewed emotional and neutral faces, but switched between two non-emotional tasks (i.e. responding to the face's age vs. gender). Data from Experiment 1 demonstrated that switching from an emotional to a non-emotional task was slower when the expression of the new face was emotional rather than neutral. This impairment was observed in both age groups. In contrast, Experiment 2 revealed that neither younger nor older adults were affected by block-wise irrelevant emotion when switching between two non-emotional tasks. Overall, the findings suggest that task-irrelevant emotion can impair task switching through reactivation of the competing emotional task set. They also suggest that this effect and the ability to shield task-switching performance from block-wise irrelevant emotion are preserved in ageing.     

汉-英双语者图片命名任务中的语码切换代价

在图片命名范式下探讨了汉-英双语者汉、英两种语言之间的语码切换代价及影响切换代价不对称性的因素.实验一中发现了汉-英双语者的语码切换代价,但语码切换代价并未表现出不对称性;在加入时间间隔（ISI）变量后,短ISI条件下,汉-英双语者的语码切换代价表现出了不对称性,表现为从第二语言到第一语言的切换代价更大;而长ISI条件下,汉-英双语者的语码切换代价是对称的.这表明,图片命名任务中可出现语码切换代价,且ISI是影响语码切换代价不对称性的重要因素,支持并丰富了对优势语言的抑制说.     

Proactive versus reactive task-set inhibition: Evidence from flanker compatibility effects

Two converging tests were used to determine whether people proactively inhibit recently performed tasks when switching to new tasks. A task-cuing paradigm was used. In each trial, the relevant stimulus was accompanied by flankers belonging either to the task performed on the immediately preceding trial (lag 1) or a more distant trial (lag 21). If the just-performed task is inhibited when switching to another task, and this inhibition declines across trials, then flanker interference should be smaller with lag 1 flankers than with lag 21 flankers. Experiment 1, following the methods of Hübner, Dreisbach, Haider, and Kluwe (2003), failed to confirm this prediction. The prediction was confirmed in Experiment 2, however, using a design modified to provide greater incentives for task-set inhibition. The results provide evidence that inhibition can be applied proactively, to reduce the ability of an abandoned task to interfere with the performance of other tasks.     

Asymmetrical switch costs in children

Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about the origins of these asymmetrical switch costs have emerged from numerous and detailed experiments with adults. There is no documented evidence of asymmetrical switch costs in children. We conducted a series of studies that examined age-related changes in asymmetrical switch costs, within the same paradigm. Similarities in the patterns of asymmetrical switch costs between children and adults suggested that theoretical explanations of the cognitive mechanisms driving asymmetrical switch costs in adults could be applied to children. Age-related differences indicate that these theoretical explanations need to incorporate the relative contributions and interactions of developmental processes and task mastery.