Characteristics and Correlates of Intraindividual Variability in Executive Control Processes

大多数科学研究关注的是平均表现(A组完成一项任务的速度比B组快多少)。不幸的是，这种对平均表现的关注在很大程度上盖过了对表现变异性的研究，例如给定个体在一系列试验中反应快或慢的波动。包括认知神经科学、神经心理学和数学建模在内的各个科学学科越来越多的共识表明，从理论上讲，认知功能的有趣方面并不能通过平均群体表现来捕捉。此外，还提出了强有力的主张，即依赖平均业绩估计可能反映了行为模式严重的过于简单化。执行功能的衡量标准，反映了我们注意重要信息或抑制无关细节的能力，特别适合于评估变异性。最近的研究结果表明，在反应潜伏期试验中，执行措施的表现波动明显，在更困难的任务条件下会增加，并与与高效执行过程有关的大脑结构有关。尽管人们对不同学科之间的可变性越来越感兴趣，但关键问题仍然存在。为了加深我们对表现变异性的本质、潜在机制和相关性的理解，本研究计划将考察三个关键的研究目标，包括：(1)直接比较认知(执行功能)、生理(步态)和大脑(取决于血氧水平或大胆反应)功能的变异性的相互竞争的定义；(2)检查各种变异性指数的变化(认知功能的波动是否与大脑激活模式的波动有关？)以及其他指标(压力、大脑结构和功能)的变化之间的联系，跨越短期(试验到试验)和长期(每年到一年)的跟踪间隔；以及(3)通过评估或操纵关键因素，如认知训练和认知负荷，确定导致变异性增加的潜在过程。

Most scientific research focuses on average performance (how much faster does group A perform a task relative to Group B). Unfortunately, this focus on mean performance has largely overshadowed research on variability in performance, such as the fluctuations in how fast or slow a given individual responds across a series of trials. Growing consensus from various scientific disciplines, including cognitive neuroscience, neuropsychology, and mathematical modeling, suggests that theoretically interesting aspects of cognitive function are not captured by mean group performance. Moreover, strong claims are made that reliance on mean performance estimates may reflect a critical oversimplification of behavior patterns. Measures of executive function, reflecting our ability to attend to important information or inhibit irrelevant detail, are particularly well suited for assessing variability. Recent findings have shown that performance fluctuations across response latency trials are pronounced for executive measures, increase under more difficult task conditions, and are associated with brain structures linked to efficient executive processes. Despite growing interest in variability across disciplines, key questions endure. To further our understanding of the nature, underlying mechanisms, and correlates of performance variability, this research program will examine three key research objectives including: (1) the direct comparison of competing definitions of variability for measures of cognitive (executive function), physiological (gait), and brain (blood oxygen level dependent or BOLD response) function; (2) the examination of associations among changes in the various indices of variability (are fluctuations in cognitive functioning linked to fluctuations in brain activation patterns?), as well as change in other indicators (stress, brain structure and function), across short-term (trial-to-trial) and long-term (year-to-year) follow-up intervals; and (3) the identification of potential processes underlying increased variability by assessing or manipulating key factors such as cognitive training and cognitive load.