Paglieri Fabio, Addessi Elsa, Sbaffi Agnese, Tasselli Maria Isabella, Delfino Alexia
Istituto di Scienze e Tecnologie della Cognizione, CNR, Roma.
J Exp Anal Behav. 2015 Jan;103(1):196-217. doi: 10.1002/jeab.118. Epub 2014 Dec 25.
Intertemporal choices create a tension between amount maximization, which would favor the larger and later option (LL), and delay minimization, which would promote the smaller and sooner reward (SS). Two common interpretations of intertemporal choice behavior are discussed: looking at LL responses as indicative of self-control, and using intertemporal choices to assess delay aversion. We argue that both interpretations need to take into account motivational confounds, in order to be warranted by data. In intertemporal choices with prepotent, salient stimuli (e.g., food amounts, typically used with nonhuman primates), LL responses could also be indicative of failed inhibition of a "go for more" impulsive response-the opposite of self-control. Similarly, intertemporal choices can be used to measure delay aversion only with respect to the subject's baseline motivation to maximize the reinforcer in question, and this baseline is not always assessed in current experimental protocols. This concern is especially crucial in comparing intertemporal choices across different groups or manipulation. We focus in particular on the effects of reward types on intertemporal choices, presenting two experimental studies where the difference in behavior with monetary versus food rewards is the product of different baseline motivation, rather than variations in delay aversion. We conclude discussing the implications of these and other similar recent findings, which are far-reaching.
跨期选择在数量最大化（倾向于更大且更晚的选项，即LL）和延迟最小化（促进更小且更早的奖励，即SS）之间产生了一种张力。本文讨论了跨期选择行为的两种常见解释：将LL反应视为自我控制的指标，以及利用跨期选择来评估延迟厌恶。我们认为，为了得到数据支持，这两种解释都需要考虑动机混淆因素。在具有优势、显著刺激的跨期选择中（例如，通常用于非人类灵长类动物的食物量），LL反应也可能表明对“追求更多”冲动反应的抑制失败——这与自我控制相反。同样，只有相对于主体最大化相关强化物的基线动机，跨期选择才能用于测量延迟厌恶，而当前的实验方案并不总是评估这种基线。在比较不同组或操作的跨期选择时，这种担忧尤为关键。我们特别关注奖励类型对跨期选择的影响，呈现了两项实验研究，其中货币奖励与食物奖励的行为差异是不同基线动机的产物，而非延迟厌恶的变化。我们在结论中讨论了这些以及其他类似近期发现的影响，这些影响意义深远。
