Hunger increases delay discounting of food and non-food rewards

How do our valuation systems change to homeostatically correct undesirable psychological or physiological states, such as those caused by hunger? There is evidence that hunger increases discounting for food rewards, biasing choices towards smaller but sooner food reward over larger but later reward. However, it is not understood how hunger modulates delay discounting for non-food items. We outline and quantitatively evaluate six possible models of how our valuation systems modulate discounting of various commodities in the face of the undesirable state of being hungry. With a repeated-measures design, an experimental hunger manipulation, and quantitative modeling, we find strong evidence that hunger causes large increases in delay discounting for food, with an approximately 25% spillover effect to non-food commodities. The results provide evidence that in the face of hunger, our valuation systems increase discounting for commodities, which cannot achieve a desired state change as well as for those commodities that can. Given that strong delay discounting can cause negative outcomes in many non-food (consumer, investment, medical, or inter-personal) domains, the present findings suggest caution may be necessary when making decisions involving non-food outcomes while hungry.

我们的估值系统如何通过稳态调节机制纠正由饥饿等不良心理或生理状态所引起的不适宜状态？研究表明，饥饿会加剧对食物奖励的折现，使得个体倾向于选择较小但较快的食物奖励而非较大但较慢的奖励。然而，目前尚不清楚饥饿如何调节非食物物品的延迟折现。本文概述并定量评估了六种可能的模型，以阐释我们的估值系统如何在饥饿这一不良状态下调节各类商品的折现。通过重复测量设计、实验性饥饿操控以及定量建模，我们发现了强有力的证据表明，饥饿导致食物的延迟折现显著增加，且对非食物商品产生了约25%的溢出效应。这些结果证实，在饥饿状态下，我们的估值系统对无法实现预期状态改变的商品的折现增加，以及对能够实现预期状态改变的商品的折现增加。鉴于强烈的延迟折现可能在许多非食物（如消费、投资、医疗或人际）领域引发负面后果，本研究结果提示，在饥饿状态下做出涉及非食物结果的决策时，应持谨慎态度。