结构限制和作业难度对双重作业绩效的影响

通过对不同双重任务的呈现间隔时间和不同任务难度的双重任务的操作研究,探讨了结构限制与资源竞争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好。(2)作业难度对双重任务的操作有明显的影响。作业难度越大,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作业难度对双重任务操作绩效的作用。本研究的实验结果进一步证实了双重任务操作的三因素假设：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独立的原因。     

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。     

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。     

单页和多页呈现设计对网页信息搜索效率及主观感受的影响

本研究以操作绩效和主观满意度为指标,对网页信息的单页和多页呈现方式进行研究。实验采用搜索任务,共有46名被试参加实验。研究结果表明：（1）在常用的页码翻页、下拉翻页、填写翻页和上页下页翻页四种多页操作方式中,页码翻页是最优的操作方式;（2）无论是在搜索绩效上还是主观满意度上,网页信息的多页呈现方式都要优于单页呈现方式。本实验结果可以为网页信息呈现设计提供科学的依据。     

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。     

认知负荷对顿悟问题解决的影响

顿悟问题解决有许多影响因素,其中认知资源的耗费会影响到工作记忆的容量及加工效果,进而影响顿悟问题解决的效果.本实验通过三种呈现时间间隔,两种活动任务(高负荷任务和低负荷任务),组合为五种实验条件,探讨了源问题与靶问题呈现时间间隔与间隔期间活动任务(即不同的认知资源耗费程度)对关键启发信息激活的影响.结果表明:认知资源的耗费是影响顿悟问题解决的重要因素,认知资源耗费越多,关键启发信息越难激活;如果没有其他信息的干扰,源靶问题之间的时间问隔越长,有助于被试对源问题中的关键启发信息的思考与归纳,进而在解答靶问题过程中就越容易提取出关键启发信息.     

Role of outcome conflict in dual-task interference

The traditional explanation for dual-task interference is that tasks compete for scarce processing resources. Another possible explanation is that the outcome of the processing required for one task conflicts with the processing required for the other task (e.g., cross talk). To explore the contribution of outcome conflict to task interference, we manipulated the relatedness of the tasks. In Experiment 1, subjects searched concurrently for names of boys in one channel and names of cities in another channel. Responses were significantly delayed when a nontarget on one channel belonged to, or was even just related to, the category designated as the target for the other channel. No comparable effects were found when the tasks were performed in isolation. Thus, the difficulty of the individual tasks is not the only determinant of how much they will interfere when combined, and there must be substantial interactions between processes carrying out the two tasks. In Experiment 2 subjects searched one channel for specific target letters and another channel for specific target digits. The nontargets in a channel were either from the same alphanumeric category as the targets for that channel or from the opposite category (i.e., the category of the targets for the other channel). It was found that although between-category search was more efficient than within-category search in single tasks, it was less efficient in dual tasks. Thus, there appear to be significant task interactions due to the confusability emerging when the nontargets of one task belong to the same category as the targets of the concurrent task. In addition, the congruence of target presence or absence on the two channels was found to have a sizeable effect. We suggest four potential sources of outcome conflict that may contribute to dual-task interference, and we conjecture that a great deal of the residual interference might result from other sorts of outcome conflict.     

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.     

Mental effort and task interference in auditory attention

Dual-task performance was examined in three experiments. The primary task was to repeat or to add one to four digits presented auditorily at a rate of 1 digit/second. This primary task was combined with three different secondary tasks in which subjects listened to a list of words either for later recognition of some of the words (Experiment 1) or for detection and a later report of a target word (Experiments 2 and 3). Different patterns of task interference were obtained. Recognition performance was sensitive to between-task variations in capacity demands but did not reflect momentary attentional demands within the primary task. Detection performance reflected both between-task and within-task variation in capacity demands of the primary task. The interference between the primary and the secondary task was mutual, with more interference when the selection-cue in the detection task was a category name than when it was the target word itself. These findings are discussed in terms of effort theory of attention and the role of attentional strategies in dual-task performance.     

Selective impairment of masked priming in dual-task performance

This study investigated the impact of divided attention on masked priming. In a dual-task setting, two tasks had to be carried out in close temporal succession: a tone discrimination task and a masked priming task. The order of the tasks was varied between experiments, and attention was always allocated to the first task—that is, the first task was prioritized. The priming task was the second (nonprioritized) task in Experiment 1 and the first (prioritized) task in Experiment 2. In both experiments, “novel” prime stimuli associated with semantic processing were essentially ineffective. However, there was intact priming by another type of prime stimuli associated with response priming. Experiment 3 showed that all these prime stimuli can reveal significant priming effects during a task-switching paradigm in which both tasks were performed consecutively. We conclude that dual-task specific interference processes (e.g., the simultaneous coordination of multiple stimulus–response rules) selectively impair priming that is assumed to rely on semantic processing.     

Electrodermal responses to sources of dual-task interference

There is a response selection bottleneck that is responsible for dual-task interference. How the response selection bottleneck operates was addressed in three dual-task experiments. The overlap between two tasks (as indexed by the stimulus onset asynchrony [SOA]) was systematically manipulated, and both reaction time and electrodermal activity were measured. In addition, each experiment also manipulated some aspect of the difficulty of either task. Both increasing task overlap by reducing SOA and increasing the difficulty of either task lengthened reaction times. Electrodermal response was strongly affected by task difficulty but was only weakly affected by SOA, and in a different manner from reaction time. A fourth experiment found that the subjectively perceived difficulty of a dual-task trial was affected both by task difficulty and by SOA, but in different ways than electrodermal activity. Overall, the results were not consistent with a response selection bottleneck that involves processes of voluntary, executive attention. Instead, the results converge with findings from neural network modeling to suggest that the delay of one task while another is being processed reflects the operation of a routing mechanism that can process only one stream of information for action at a time and of a passive, structural store that temporarily holds information for the delayed task. The results suggest that conventional blocked or event-related neuroimaging designs may be inadequate to identify the mechanism of operation of the response selection bottleneck.     

Texture-based tasks are little affected by second tasks requiring peripheral or central attentive fixation.

Experiments are described in which observers attempted to perform concurrently two separate visual tasks. Two types of tasks were used: the identification of a T-shaped or L-shaped letter target, and the detection or localization of a texture element of unique orientation (texture target) within a dense texture. Combining these tasks to form various task pairs, performance as a function of stimulus onset asynchrony (SOA) was established separately for each task in a pair. In addition, performance was measured when each task was carried out by itself. When paired, two identification tasks (T or L) on (two) letter targets required a significantly larger SOA than either identification task by itself. This outcome suggests the involvement of serial performance and competition for a limited resource, confirming that letter identification requires attentive fixation. However, when the identification of a central letter target was paired with the localization (upper or lower hemifield) of an eccentric texture target, performance in the pair was comparable to performance of each task by itself. This suggests parallel performance and a lack of conflict over resources. The outcome was similar when the identification of an eccentric letter target was paired with the detection (present or absent) of an eccentric texture target. These results are consistent with the possibility that localization and detection of a textural singularity do not require attentive fixation.     

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.