结构限制和信息干扰对双重作业绩效的影响

研究通过改变双重任务呈现的间隔时间来探讨结构限制与信息干扰对双重任务操作绩效的影响。实验结果表明：(1)两种作业呈现的间隔时间对双重任务操作绩效有明显的影响。间隔时间越大,双重任务的作业绩效越高。(2)信息干扰对双重任务的操作有明显的影响。信息干扰越大,双重任务的操作绩效越差。(3)两个作业呈现的间隔时间不同并不影响信息干扰对双重任务操作绩效的作用。根据实验结果,该研究提出了三因素假设：结构限制、信息干扰和资源竞争是影响双重任务操作绩效的三个主要因素。     

结果冲突与作业难度对双重作业绩效的影响

运用单作业和双作业操作探讨结果冲突与作业难度对双重作业绩效的影响。结果表明：（１）信息干扰对双作业操作有着明显的影响。信息干扰越大,结果冲突效应越大,双作业操作绩效越差。（２）作业难度对双作业绩效有明显影响。作业难度越大,双作业操作绩效越差。根据实验结果,本研究提出了双因素假设：信息干扰和资源竞争是影响双作业操作绩效的两个主要因素。     

双重作业的颜色编码方式对作业绩效的影响

研究探讨了不同颜色编码方式对双重任务操作绩效的影响。实验结果证明：若采用同类颜色编码方式,同时操作的两种作业就会产生结构限制,降低双重任务操作绩效;相反,若采用异常颜色编码方式,将有效地减少双重任务操作的结构限制,使双重任务的操作绩效得到提高。     

双作业的信息编码方式对作业绩效的影响

采用单作业和双作业操作,探讨了不同信息编码方式对双作业操作绩效的影响。实验结果证明：若采用相同的信息编码方式,同时操作的两种作业就会产生相互干扰,降低双作业操作绩效;相反,若同时操作的两种作业采用不同信息编码方式将有效地减小双作业操作的相互干扰,使双作业操作的绩效得到提高。     

双作业信息输入通道对作业绩效的影响

采用单作业和双作业操作,探讨了不同信息输入通道对双作业操作绩效的影响。实验结果证明：若采用相同的信息输入通道,同时操作的两种作业就会产生相互干扰,降低操作绩效;相反,若采用不同信息输入通道,双作业之间的相互干扰将减小,作业绩效得到提高。     

作业中断对任务绩效的影响及心理疲劳的调节作用

作业中断会对中断后行为绩效产生影响,探讨不同疲劳状态下中断对作业绩效影响的认知机制将有助于完善和发展中断的认知理论。本研究采用事件相关电位(ERP),通过在不同心理疲劳状态下执行数学题任务中断、暂停中断和不中断的空间2-back任务,结合行为数据和ERPs结果,分析作业中断对任务绩效的影响以及心理疲劳在其中的调节作用。实验结果发现,中断后诱发的P200和P300振幅显著提高,作业中断使得主任务的注意力资源下降,任务中断的无关信息干扰了主任务工作记忆,而疲劳状态则进一步加剧了中断对注意资源、工作记忆及行为绩效的负面效应。本研究在揭示作业中断认知过程及疲劳对其影响机理的同时,也支持了中断的目标记忆模型。     

不同反应方式对双作业操作信息干扰的影响

本研究采用单作业双作业操作,探讨了不同反应方式对双作业操作信息干扰的影响。实验结果证明;若采用相同的反应方式,同时操作的两种作业就会产生相互干扰,降低作业绩效;相反,若采用不同反应方式将减小双作业操作的相互干扰,提高双作业操作绩效。     

对交迭任务记忆的实验研究(Ⅱ)

对交迭记忆任务的实验室模拟实验结果表明:(1)任务交迭类型、交迭任务数和任务呈现间隔时间都是影响交迭记忆业绩的因素。交迭记忆业绩随任务交迭类型的复杂程度提高而降低,随呈现间隔时间的延长而提高;在复式交迭类型中,随交迭任务数的增多而降低。从而说明了时间繁忙和信息加工强度是心理负荷的两个因素。(2)据实验结果求出了在本实验情境下的交迭记忆曲线公式。     

团队作业与团队互动两类共享心智模型的发展特征

共享心智模型指团队成员关于团队作业、策略、团队情境、团队互动等的共同的知识结构,根据内容不同可以分为团队作业模型和团队互动模型两类。该研究通过实验室实验探讨两类共享心智模型的发展特征。132名大学生组成44个3人团队,随机分为团队绩效反馈组和无团队绩效反馈组。采用相似性评定法在团队执行作业前、中、后三次测量两类共享心智模型。结果发现：（1）共享心智模型随团队运作时间增加而发展;（2）团队互动模型形成和发展的难度高于团队作业模型;（3）团队绩效反馈对两类心智模型发展的作用不同,反馈加速了团队作业模型的发展速度,但却是团队互动模型能否得以发展的决定性因素。两类共享心智模型的不同发展特征应归因于两者特异性高低的不同     

辨别作业难度对返回抑制时间进程的影响

在返回抑制范式下,利用线索一靶子模式和辨别作业进行了两个实验,探讨辨别作业难度对返回抑制的影响。以大学生为被试。实验一对辨别作业难度采用组间设计;实验二采用组内设计。结果发现,无论是组间比较(实验一),还是组内比较(实验二)．复杂辨别作业条件下返回抑制出现时间均比简单辨别作业晚,表明作业难度对返回抑制的时间进程有显著影响。该结果对返回抑制的机制研究有一定的意义。     

System reconfiguration, not resource depletion, determines the efficiency of visual search

We examined two theories of visual search: resource depletion, grounded in a static, built-in brain architecture, with attention seen as a limited depletable resource, and system reconfiguration, in which the visual system is dynamically reconfigured from moment to moment so as to optimize performance on the task at hand. In a dual-task paradigm, a search display was preceded by a visual discrimination task and was followed, after a stimulus onset asynchrony (SOA) governed by a staircase procedure, by a pattern mask. Search efficiency, as indexed by the slope of the function relating critical SOA to number of distractors, was impaired under dual-task conditions for tasks that were performed efficiently (shallow search slope) when done singly, but not for tasks performed inefficiently (steep slope) when done singly. These results are consistent with system reconfiguration, but not with resource depletion, models and point to a dynamic, rather than a static, architecture of the visual system.     

When underadditivity of factor effects in the Psychological Refractory Period paradigm implies a bottleneck: Evidence from psycholinguistics

The Psychological Refractory Period (PRP) paradigm is a dual-task procedure that can be used to examine the resource demands of specific cognitive processes. Inferences about the underlying processes are typically based on performance in the second of two speeded tasks. If the effect of a factor manipulated in Task 2 decreases as the stimulus onset asynchrony (SOA) between tasks decreases (underadditivity), the normative inference is that the effect of this factor occurs prior to a limited-capacity central processing mechanism. In contrast, if the effect of a factor is additive with SOA then the inference is that this indexes a process that either uses a limited-capacity central processing mechanism or occurs after some process that uses this mechanism. A heretofore unidentified exception to this logic arises when Task 2 involves two separate processes that operate in parallel, but compete. Interference with one process in Task 2 because of work on Task 1 will eliminate or reduce competition within Task 2 and is hence manifest as an underadditive interaction with decreasing SOA. This is illustrated here by reference to a PRP experiment in which the ubiquitous effect of spelling-to-sound regularity on reading aloud time is eliminated at a short SOA and by consideration of three converging lines of investigation in the PRP paradigm when Task 2 involves reading aloud.     

What causes residual dual-task interference after practice?

Practice can dramatically reduce dual-task interference, but typically does not eliminate interference entirely. Residual interference after practice is especially large with certain non-preferred modality pairings (e.g., auditory–manual and visual–vocal). Does this residual interference imply the existence of a persistent central-processing bottleneck? To address this question, we transferred participants with previous dual-task practice to a psychological refractory period design. Although we observed residual dual-task costs in all four experiments, there was no evidence for a bottleneck, even with non-preferred modality pairings. We conclude that practice can eliminate the bottleneck limitation, but performance is still subject to other sources of interference, such as competition between central codes of the two tasks.     

Combining letter-matching and tone discrimination: Evidence of automatic perceptual and spatial congruity effects

Dual task and priming paradigms were combined to investigate the distinction between automatic and attentional processes. Subjects in two experiments performed a primed letter-matching and a tone discrimination task separately and concurrently. The interval between prime onset and letter pair (SOA) was varied from 50 to 500 msec. Cost-benefit analyses in Experiment 1 indicated that primes that matched target letter pairs began to facilitate performance at an SOA of 150 msec. Primes inhibited performance when they mismatched identical letter pairs at SOA 100. In the dual-task situation, the benefits of priming letter targets were reflected in probe latencies with no evidence of concurrent costs in tone latencies. Experiment 2 revealed that two tasks could be primed simultaneously as effectively as when each was primed alone. Findings are discussed in reference to Posner and Snyder's (1975a, 1975b) two-process theory of priming and the applicability of a secondary task technique.     

Dual-task processing in younger and older adults: similarities and differences revealed by fMRI

fMRI was used to explore age differences in the neural substrate of dual-task processing. Brain activations when there was a 100 ms SOA between tasks, and task overlap was high, were contrasted with activations when there was a 1000 ms SOA, and first task processing was largely complete before the second task began. Younger adults (M=21 yrs) showed activation in dorsolateral prefrontal cortex and in parietal areas as well as in ventral medial frontal cortex and sub-lobar areas. Activations in older adults (M=71 yrs) did not differ significantly from younger adults except for higher activations in occipital and polar prefrontal cortex. The results were well fit by a model with two networks managing dual-task interference, a medial prefrontal network that detects changes in the stimulus situation and maps them to associated changes in the valence of response mappings and a lateral frontal-parietal network that initiates and carries out the shift from one task to the other. The additional activations in older adults as a group and the correlations of individual differences in activation with performance were consistent with recruitment within each of these networks. Alternative explanations such as hemispheric asymmetry reduction and reactive rather than proactive processing in older adults were not supported.     

Multiple spatial correspondence effects on dual-task performance

Three dual-task experiments were conducted to examine whether the underadditive interaction of the Simon effect and stimulus onset asynchrony (SOA) on Task 2 performance is due to decay. The experiments tested whether the reverse Simon effect obtained with an incompatible stimulus-response (S-R) mapping would show an overadditive interaction with SOA, as predicted by R. De Jong, C.-C. Liang, and E. Lauber's (1994) dual-process model. Tone or letter identification tasks with vocal or keypress responses were used as Task 1. Task 2 was keypresses to arrow direction (or letter identity in Experiment 1). For all experiments, the normal Simon effect showed an underadditive interaction with SOA, but the reverse Simon effect did not show an overadditive interaction. The results imply that the dual-process model is not applicable to the dual-task context. Multiple correspondence effects across tasks implicate an explanation in terms of automatic S-R translation.     

Involuntary strategy-dependent dual task performance

Previous studies showed that some dual tasks can be performed simultaneously without costs. Yet, a variable SOA between the inputs to such tasks leads to strategic, often involuntary, prioritization of one of the two tasks. Here we explore the boundary conditions for this involuntary or exogenous strategy. In Experiment 1, subjects were initially trained on dual task performance where the input to the two tasks is presented simultaneously (0 SOA). We used two tasks that under such conditions can be performed without costs and indeed subjects displayed perfect sharing of the tasks. Subjects then performed the same two tasks but with a variable SOA (0, 50, 150, 800?ms). This manipulation led to a serial-like performance of the two tasks even in trials with 0 SOA. In Experiment 2, subjects participated in eight sessions. Within each session, they performed in alternation blocks with a fixed 0 SOA and blocks with a variable SOA. Subjects displayed perfect sharing in the pure 0 SOA blocks but performed the two tasks serially in the mixed SOA blocks despite receiving identical instructions. These findings demonstrate that task context is a powerful factor in dual task performance and may lead subjects to involuntarily exhibit dual task costs even in conditions where they can perform the tasks without any costs. Moreover, these findings strongly suggest that costs observed in PRP studies reflect the use of such exogenous strategies rather than a general structural dual task limitation.     

Rhyming abilities in a dual-task in school-age children who stutter

PurposeWe compared school-age children who stutter (CWS) and age and gender matched control participants (CWNS) in a dual-task involving a word-level rhyming task and a tone task involving pitch decisions.MethodsParticipants were 30 children (CWS, n = 15) between 7 and 16 years. Auditory word – picture stimuli pairs from the rhyme task were categorized into nonrhyme (e.g., bear-cart), rhyme (e.g., bear-pear), and replica (e.g., bear-bear) categories. The effort associated with managing resources in the dual-task was varied through the manipulation of stimulus onset asynchrony (SOA) between the stimuli of the two tasks. Mixed methods analyses of the response time (RT, ms) and error (%) data were conducted with Group, Category, and SOA as the fixed effects and participants as the random effect. Age and phoneme awareness skills were included in the analyses.ResultsMore rhyming errors and a significant positive correlation between rhyming errors and age was observed in the CWS compared to the CWNS. Compared to the CWNS, a higher percentage of rhyming errors was observed in the rhyme than the nonrhyme and replica categories in the CWS in both the SOA conditions, and this effect was influenced by age and phoneme awareness skills. Analysis of the tone task data indicated that a subgroup of CWNS with higher phoneme awareness skills showed reduced RT difference between the long and the short SOA conditions thereby suggesting higher efficiency with resource allocation for dual tasking. Task-specific differences between the CWS and CWNS are interpreted to suggest limitations in the encoding of the phonological aspects of covert speech in a dual-task.