Ageing and distraction: The effect of central and peripheral cognitive and sensory systems

衰老涉及到感觉和认知过程的变化。随着年龄的增长，这两种情况都可能会增加忽视分心问题的难度。然而，感觉过程对克服分心的影响很少被控制或评估，大多数研究混淆了年龄和感觉丧失。至关重要的是，充分理解衰老过程中的分心现象，需要将外围、感觉和认知过程与更核心的认知变化分开。此外，理论模型主要关注来自同一感官通道的分心，而在现实生活中，我们面临着来自多个感官的分心。因此，博士项目的目的是扩展当前基于相同意义上的分心的理论模型，以包括来自其他感觉形式的分心，以及分离认知和感觉过程的作用。该项目还有可能在维持老年人的日常运作和独立方面产生社会影响，老年人有时可能会因复杂和分散注意力的情况而感到不知所措。为了更详细地研究分心，需要一种方法来消除这些不同处理阶段的歧义。分心的干扰可能来自大脑对刺激输入的表达之间的干扰，或者来自对这些刺激的反应之间的干扰。在我们之前的研究中，我们使用了一种改进的颜色词Stroop任务，其中将反应选项配对，以便分心可以提示对所关注的特征的不同反应(反应/认知干扰)，或者分心和参与特征在感觉输入上不同，但共享相同的反应(刺激/感觉干扰)。我们的发现表明，老年人在感觉加工的早期阶段保持了抑制跨通道分心的能力，从而保持了避免跨通道分心的能力。以前工作的另一个限制是，听觉和视觉分心没有在对称设计中进行测试，在这种设计中，每种通道的分心都以相同的实验和方式进行了测试。因此，博士项目的第一阶段将使用一种新的完全对称的任务设计来比较健康的老年人和年轻人在忽略单峰和跨模式分心时感觉和认知过程之间的相互作用。参与者被要求对音调或灯光的位置做出反应，而忽略书写或说话的位置(上/下/左/右)。这样做的好处是，两种感觉的表现都是使用相同的测量方法来评估的，其中信号的强度在心理测量学上是匹配的。这项工作的一个可能的扩展是评估感觉质量对跨模式分心的影响。这可以通过a)系统地改变向具有良好感觉能力的人显示的刺激的质量和/或通过测量通过白内障摘除和助听器的使用来改善感觉丧失的效果来实现。第二种可能的探索途径是将基于实验室的发现扩展到更现实的任务和情况，基于之前的参与/共同创造工作，强调老年人发现(图书)商店特别分散注意力。这代表着应用认知脑研究的重大变革，具有潜在的现实应用。

Aging involves changes in both sensory and cognitive processes. Both of these are likely to contribute to increased difficulty ignoring distractions with age. However, the influence of sensory processes on overcoming distractions has rarely been controlled for or assessed, with the majority of studies confounding age and sensory loss. Critically, fully understanding distraction in ageing requires separating peripheral, sensory, processes from more central, cognitive change. Moreover, theoretical models have largely focused on distractions from within the same sensory modality, yet in real life, we are faced with distractions from multiple senses. The aim of the PhD project is therefore to extend current theoretical models based on distractions within the same sense to include distractions from other sensory modalities, as well as to isolate the role of cognitive and sensory processes. The project also has the potential for societal impact in terms of maintained daily functioning and independence of older citizens, who might sometimes feel overwhelmed by complex and distracting situations. In order to investigate distraction in more detail, an approach that can disambiguate these different stages of processing is needed. Interference from distraction can arise from interference between the brain's representations of stimulus inputs or from interference between the responses to those stimuli. In our previous research we used a modified colour-word Stroop task where response choices were paired so that the distraction could either cue a different response to the attended feature ('response/cognitive interference') or the distraction and attended feature differed in sensory input but share the same response ('stimulus/sensory interference'). Our findings suggested that older people maintain the ability to inhibit cross-modal distractors at early, sensory processing, stages and, thus maintain the ability to avoid cross-modal distraction.A further limitation of previous work is that auditory and visual distractions have not been tested in a symmetric design, where distractions in each modality have been tested in the same experiment and in the same way. The first stage of the PhD project will therefore use a new fully symmetric task design to compare the interactions between sensory and cognitive processes in ignoring unimodal and cross-modal distraction in healthy older and younger adults. Participants are asked to respond to the location of a tone or light while ignoring written or spoken locations (up/down/left/right). This has the advantage that performance in both senses is evaluated using identical measures where the strength of the signal is psychometrically matched. One possible extension of this work is to assess the impact of sensory quality on cross-modal distraction. This can be done by a) systematically varying the quality of the stimuli shown to people with good sensory abilities and/or by measuring the effects of ameliorating sensory loss via cataract removal and the use of hearing aids. A second possible avenue of exploration is to extend the lab-based findings to more real-life tasks and situations, based on previous engagement/co-creation work highlighting that older people find (book) shops particularly distracting. This represents a significant step-change of applied cognitive brain research with potential real-world applications.