Behavioural Science Institute, Radboud University Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, the Netherlands.
University of Amsterdam, Amsterdam School of Economics (CREED) and Tinbergen Institute, Amsterdam, the Netherlands.
Neuroimage. 2019 Jan 15;185:236-244. doi: 10.1016/j.neuroimage.2018.10.008. Epub 2018 Oct 5.
We are often presented with choices that differ in their more immediate versus future consequences. Interestingly, in everyday-life, ambiguity about the exact timing of such consequences frequently occurs, yet it remains unknown whether and how time-ambiguity influences decisions and their underlying neural correlates. We developed a novel intertemporal fMRI choice task in which participants make choices between sooner-smaller (SS) versus later-larger (LL) monetary rewards with systematically varying levels of time-ambiguity. Across trials, delay information of the SS, the LL, or both rewards was either exact (e.g., in 5 weeks), of low ambiguity (4 week range: e.g., in 3-7 weeks), or of high ambiguity (8 week range: e.g., in 1-9 weeks). Choice behavior showed that the majority of participants preferred options with exact delays over those with ambiguous delays, indicating time-ambiguity aversion. Consistent with these results, the ventromedial prefrontal cortex showed decreased activation during ambiguous versus exact trials. In contrast, intraparietal sulcus activation increased during ambiguous versus exact trials. Furthermore, exploratory analyses suggest that more time-ambiguity averse participants show more insula and dorsolateral prefrontal cortex activation during subjective value (SV)-coding of ambiguous versus exact trials. Lastly, the best-fitting computational choice models indicate that ambiguity impacts the SV of options via time perception or via an additive ambiguity-related penalty term. Together, these results provide the first behavioral and neural signatures of time-ambiguity, pointing towards a unique profile that is distinct from impatience. Since time-ambiguity is ubiquitous in real-life, it likely contributes to shortsighted decisions above and beyond delay-discounting.
我们经常面临着即时后果和未来后果不同的选择。有趣的是，在日常生活中，这种后果的确切时间往往存在模糊性，但目前尚不清楚时间模糊性是否以及如何影响决策及其潜在的神经相关性。我们开发了一种新的跨时 fMRI 选择任务，参与者在具有系统变化的时间模糊性水平的情况下，在更快更小（SS）与更晚更大（LL）的货币奖励之间做出选择。在整个试验中，SS 和 LL 的延迟信息要么是精确的（例如，在 5 周内），要么是低模糊的（4 周范围：例如，在 3-7 周内），要么是高模糊的（8 周范围：例如，在 1-9 周内）。选择行为表明，大多数参与者更喜欢具有精确延迟的选项，而不是具有模糊延迟的选项，这表明了对时间模糊性的厌恶。与这些结果一致的是，腹内侧前额叶皮层在模糊与精确试验中表现出的激活减少。相比之下，顶内沟在模糊与精确试验中表现出的激活增加。此外，探索性分析表明，在对模糊与精确试验的主观价值（SV）编码中，对时间模糊性更厌恶的参与者表现出更多的岛叶和背外侧前额叶皮层的激活。最后，最佳拟合的计算选择模型表明，模糊性通过时间感知或通过附加的模糊相关惩罚项影响选项的 SV。总之，这些结果提供了时间模糊性的第一个行为和神经特征，表明了一种独特的模式，与不耐烦不同。由于时间模糊性在现实生活中无处不在，它可能会导致在考虑到时间折扣之外的短视决策。
