The influence of sequentially changing reward prospect on cognitive flexibility during (voluntary) task switching

同时处理两项（或更多）任务需要认知灵活性，与单一任务相比，这与表现下降有关。在认知心理学中，任务切换范式已经成为一种流行的工具，用于研究特定类型的多任务行为，即以顺序和随机顺序执行多个任务。在这种范式中，任务切换提供了认知灵活性，而任务重复则受益于认知稳定性。这使得任务切换范式成为研究两种对抗控制模式（即灵活性和稳定性）相互作用的理想工具。考虑到成功的多任务处理在现代社会中越来越重要，有必要确定不同的方法来激励灵活和稳定的行为。最近的证据（Shen & Chun, 2011; Fröber & Dreisbach，正在审查中）表明，预期奖励幅度的增加增加了灵活性，而不变的高奖励前景增加了稳定性：与不变的高奖励前景相比，预先确定的任务切换更容易，故意切换任务的意愿也更强。本研究的目的是进一步探讨在（自愿）任务转换过程中，奖励前景的顺序变化对稳定性和灵活性的影响。在第一个资助期的一部分，我们希望通过顺序改变奖励幅度来研究认知灵活性调节的边界条件。因此，我们将操纵全局上下文参数，如被迫与自愿任务切换的比例，给予参与者的具体指示（关于如何自由选择），绝对奖励与相对奖励的数量，以及不同的任务难度。在另一部分，我们将重点关注任务期望和奖励期望的相互作用。增强的认知灵活性应该有助于适应意外事件。因此，我们想要研究在违背预期和增加不确定性的情况下，使用不同的自愿和强制任务切换程序，顺序变化的奖励前景如何调节绩效。本研究计划的首要目标是加深我们对全球环境参数和动机如何调节认知灵活性过程的理解。因此，该项目为第二组优先项目（灵活性）做出了贡献。

Attending to two (or more) tasks at the same time requires cognitive flexibility and is associated with performance decrements as compared to single task performance. In cognitive psychology, the task switching paradigm has become a popular tool to investigate a specific kind of multitasking performance, namely performing more than one task in a sequential and random order. In this paradigm, task switches afford cognitive flexibility, whereas task repetitions benefit from cognitive stability. This makes the task switching paradigm an ideal tool to investigate the interplay of two antagonistic control modes, namely flexibility and stability. Considering the increasing importance of successful multitasking performance in modern society it is essential to identify ways to differentially motivate flexible and stable behavior. Recent evidence (Shen & Chun, 2011; Fröber & Dreisbach, under review) suggests that specifically increases in expected reward magnitude increase flexibility whereas the prospect of unchanged high reward increases stability: Predetermined task switches are facilitated and the willingness to deliberately switch the task is increased as compared to unchanged high reward prospect. Aim of the proposed research program is to further investigate how sequential changes in reward prospect differentially influence stability versus flexibility during (voluntary) task switching. In one part of the first funding period, we want to investigate the boundary conditions of the modulation of cognitive flexibility by sequentially changing reward magnitudes. Therefore, we will manipulate global context parameters like the ratio of forced to voluntary task switching, specific instructions given to the participant (on how to choose freely), the absolute vs. relative amount of reward prospect, and varying task difficulties. In the other part, we will focus on the interaction of task expectancies and reward expectancies. Increased cognitive flexibility should facilitate adaptation to unexpected events. Therefore, we want to investigate how sequentially changing reward prospect modulates performance under violations of expectation and increased uncertainty using different procedures of voluntary and forced task switching. The overarching goal of this research program is to deepen our understanding of how global context parameters and motivation modulate processes of cognitive flexibility. As such, the project contributes to the second cluster of the priority program (Flexibility).