Exploring the effects of learning and motivation on visual cognition

为了保持健康的生活方式，人们需要能够选择健康的选择，即使周围有诱人的选择。例如，某人可能计划减肥，但当突然注意到披萨的广告时，他或她吃东西的动机可能会急剧上升，压倒了先前优先考虑的饮食。这是因为驱使一个人做出某些选择的精神状态可以突然出现，并且仅仅通过接触物体和信息就可以启动。这些刺激被称为激励线索，它们通过学习获得自发激发行为的能力。这些刺激也能有效地吸引我们的眼球，填充我们的思想，有时会让我们难以集中精力完成手头的任务。我们项目的目的是研究激励线索如何影响感知和认知，因为这些关键过程是行为选择的前驱。对刺激线索做出的不恰当选择被认为是暴食/酗酒的主要原因，是戒毒后戒断复发的主要原因，也是一些人，尤其是青少年，从事冲动、冒险行为的主要原因。另一方面，在多任务的情况下，激励线索可能是有帮助的，因为它们允许人们以最佳方式对新场景快速做出反应。这个项目将有助于确定激励线索如何以及何时帮助和损害视觉认知任务的表现。我们对这个话题的兴趣源于我们最近的研究表明，激励线索可以非常有效地获得大脑视觉认知网络的瞬间专属访问。视觉认知网络的能力有限，需要一种选择机制来处理最相关的信息。视觉选择似乎是通过一个竞争的过程起作用的，大脑提供偏向于处理一种刺激而不是另一种刺激。我们假设激励线索激活了两种不同类型的加工偏差，一种基于主观价值，另一种基于唤醒。我们认为这些偏见有助于激励线索在不同阶段控制视觉认知。该项目将通过三个系列的健康年轻人实验和第四个系列的青少年实验（博士项目）来验证我们的假设。我们还将测试这样一种观点，即那些特别容易被激励线索分散注意力和不恰当地激励的人，在学习过程中会表现出异常强烈的视觉倾向。如果是这样，学习过程中的行为可以作为控制动机（如冲动）问题的风险指标。在我们的实验中，参与者将学会将适度的金钱奖励和惩罚与不同的视觉对象联系起来，这样这些对象就可以作为激励（或抑制）线索。然后，参与者将执行涉及这些线索的简单视觉任务。我们预测，不同任务的表现将取决于线索的唤醒值是高还是低，或者是主观价值是高还是低。我们还将监测学习过程中的视觉定向（眼球运动），以探索个体差异，并记录参与视觉任务时的脑电图（EEG），以便我们可以测试我们的预测，即偏见在视觉处理过程中以不同的方式在不同的时间起作用。在这个项目中进行的工作将加深对学习和动机如何影响视觉注意和视觉短期记忆的理解。重要的是，该项目是在一个发达的神经生物学框架内设置的，因此这些发现将与大脑机制如何与注意力和记忆相互作用的理论相关。这一理解上的进步将为理解动机障碍（如成瘾、暴饮暴食）是如何发生的提供关键的一块拼图，并为如何治疗提供洞见。

To maintain a healthy lifestyle, people need to be able to choose healthy options even when surrounded by tempting alternatives. For example, someone may plan to lose weight, but when an advertisement for pizza is suddenly noticed, his or her motivation to eat may rise sharply, overriding a previous priority to diet. This is because the state of mind that drives a person to make certain choices can arise suddenly and be initiated simply by exposure to objects and information. These stimuli are called incentive cues and they acquire their power to spontaneously motivate behaviour through learning. Such stimuli are also effective at catching our eye and filling our thoughts, sometimes making it difficult to concentrate on the task at hand. The aim of our project is to investigate how incentive cues affect perception and cognition because these critical processes are precursors to behavioural choice. Inappropriate choice in response to incentive cues is thought to be a leading cause of binge eating/drinking, relapse from abstinence in recovering drug addicts, and why some people, especially adolescents, engage in impulsive, risky behaviour. On the other hand, in multi-tasking situations, incentive cues can be helpful because they allow people to rapidly respond in optimal ways to new scenarios. This project will help identify how and when incentive cues help and hurt performance in visual cognition tasks.Our interest in this topic stems from our recent work showing that incentive cues can be highly effective at gaining momentary, exclusive access to the brain's visual cognition network. It is well established that the visual cognition network is severely limited in capacity and requires a selection mechanism so that only the most relevant information is processed. Visual selection appear to work by a process of competition, with the brain supplying biases favouring the processing of one stimulus over another. We hypothesise that incentive cues activate two different types of processing bias, one based on subjective value and the other based on arousal. We think these biases help incentive cues gain control over visual cognition at different stages. The project will test our hypotheses in three series of experiments on healthy young adults and a fourth series involving teenagers (a PhD project). We will also test the idea that people who are especially likely to be distracted and motivated inappropriately by incentive cues will show an unusually strong propensity to visually orient to cues during learning. If so, behaviour during learning could be used as an indicator of risk for problems in controlling motivation (as in impulsivity). In our experiments participants will learn to associate modest monetary rewards and punishers with different visual objects so that those objects can later act as incentive (or disincentive) cues. Then, participants will perform simple visual tasks involving these cues. We predict that performance on different tasks will be depend on whether cues are high versus low in arousal value or are high versus low in subjective value. We will also monitor visual orienting (eye movements) during learning to explore individual differences and also record the electroencephalogram (EEG) during engagement with visual tasks so that we can test our predictions that biases act at different times and in different ways during visual processing. The work conducted in this project will develop understanding of how learning and motivation influence visual attention and visual short-term memory. Importantly, the project is set within a well-developed neurobiological framework, so that findings will be relevant to theories of how brain mechanisms underlying reward learning interact with attention and memory. This advance in understanding will provide a crucial piece of the puzzle concerning how motivational disorders (e.g., addiction, overeating) occur and provide insight into how they might be treated.