Investment decisions in grey squirrels: the role of future discounting and executive control (Ref: 4264)

投资行为必然包含对未来的规划。它可以在不同的物种中采取多种形式，并需要一定程度的执行控制：投资者需要禁止立即使用一项资产，以便为不可避免地不确定的未来储存资产。投资决策为了解动物对未来的预期提供了一个窗口，并且可以预期其会随着生命史参数的变化而变化。灰松鼠是研究投资的理想模型物种，因为它们是天生多产的投资者，在食物充足的时候储存坚果，在食物匮乏的时候提供可靠的食物来源。松鼠不仅要决定是藏起来还是吃掉食物，而且藏起来本身就涉及到一系列捕食和偷窃的风险权衡，这与食物的价值是共同变化的。因此，投资决策直接反映了未来的贴现，应该与执行控制权紧密联系在一起。项目目标和方法这个博士项目将调查未来贴现和执行控制在野生灰松鼠投资决策中的作用，作为对生活在埃克塞特大学校园里的松鼠进行长期实地研究的一部分。有两个关键目标：开发可靠的松鼠执行控制分析方法，记录它们的投资决策和成功食物回收的结果，作为延迟满足的成本和收益的现实衡量标准；从综合模型中生成和测试缓存行为的预测，这些模型既考虑了最佳觅食（来自行为生态学传统），也考虑了折扣和执行控制的认知机制（来自实验/认知心理学）。通过设计实地实验来验证执行控制的抽象实验室测试，学生将在自由生活的松鼠中产生可靠的执行控制措施，并测量它们自然投资决策的结果。学生将建立基于执行控制和未来贴现的适应性投资行为的数学模型，以生成预测，并通过收集野外野生松鼠的实验数据进行测试。

Investment behaviour necessarily entails planning for the future. It can take many forms across species, and requires some degree of executive control: investors need to inhibit immediate use of an asset to store it away for a future which is, inevitably, uncertain. Investment decisions provide a window into an animal's expectations about the future and can be expected to vary with life-history parameters. Grey squirrels are an ideal model species for studying investment because they are natural and prolific investors, storing nuts during times of plenty to provide a reliable source of food when it is scarce. Squirrels not only decide whether to cache or eat a food item, but caching itself involves a series of predation and pilferage risk trade-offs, which co-vary with food value. As such, investment decisions directly reflect future discounting and ought to be tightly linked to executive control.Project Aims and MethodsThis PhD project will investigate the role of future discounting and executive control in investment decisions made by wild grey squirrels, as part of a long-term field study of squirrels living on the University of Exeter campus. There are two key aims: develop reliable assays of executive control in squirrels and record their investment decisions and outcomes in terms of successful food recovery, as a real-life measure of the costs and benefits of delaying gratification;generate and test predictions of caching behaviour from integrative models that consider both optimal foraging (from the behavioural ecology tradition) and the cognitive mechanisms of discounting and executive control (from experimental/cognitive psychology).By devising field experiments to verify abstract laboratory tests of executive control, the student will generate reliable measures of executive control in free-living squirrels and measure the outcomes of their natural investment decisions. The student will construct mathematical models of adaptive investment behaviour based on executive control and future discounting, to generate predictions that he/she will test by collecting experimental data on wild squirrels in the field.