Poverty, Stress, and Discounting: A potential micro-mechanism for behavior change

项目摘要 受各种疾病影响的人，如注意力缺陷多动障碍、强迫性赌博行为、尼古丁 上瘾和酗酒有一个共同的特征：反常的高冲动。特别是，他们倾向于立即行动，而不是 延迟的奖励。这种主观价值随着时间的推移而减少的情况被称为临时贴现。陡峭的时间 折扣已被证明与负面结果相关，而减少折扣的干预措施 显示出积极的福利效应。 然而，令人惊讶的是，几乎没有证据表明时间偏好是如何产生的，以及哪些环境因素塑造了这种偏好 他们。这一建议检验了一个简单的假设，即短视的时间偏好是如何内生的。 具体地说，我们假设贫困导致压力，压力导致短视的时间偏好，以及 目光短浅的偏好反过来会加剧贫困。因此，我们的提案试图确定一个潜在的微观机制 来改变行为。为了建立这种机制的通用性，我们将在两个开发环境中进行实验 和发达国家，无论是在实验室还是在实地；我们的目标是在所有研究中建立因果关系，并使用 新的福利措施(皮质醇和细胞因子)。 首先，在一项实验室实验中，我们问压力是否对时间折现有因果影响；我们在 并随后衡量其对时间贴现的影响。这项实验将揭示压力是否会导致 短视的决策。 在第二项研究中，我们询问贫困是否会导致压力和短视的选择。我们开发了一个新的实验室 模仿贫困的一些特征的范式，然后问a)这种操纵是否增加了压力水平 标记物皮质醇和α-淀粉酶，以及b)是否“贫穷”的人比其他人表现出更高的时间折扣率。这 结果表明，贫困可能会导致压力和短视的选择。 第三项研究是在实地和发展中国家进行的，询问贫困增加对 行为。我们利用了肯尼亚南部马赛人的一项独特的自然实验：使用降雨数据作为 工具变量，我们可以确定外源性贫困增加对压力和时间的因果影响 打折。 最后，第四项研究检验了相反的问题，即外生贫困减少的影响。 压力会导致更有远见的决策。这项研究将包括在肯尼亚的一项随机对照试验， 随机选择的贫困户获得无条件现金转移、免费医疗保险或不干预。 通过这些外生干预，我们可以识别脱贫对行为的因果效应。加在一起，这些 研究将回答上述短视决策的候选机制是否经得起因果关系 审查，从而确定一个潜在的微观机制的行为改变。(29行)

Project Summary Persons affected by conditions as diverse as Attention Deficit Hyperactivity Disorder, compulsive gambling behavior, nicotine addiction, and alcoholism share a common trait: abnormally high impulsivity. In particular, they tend to prefer immediate to delayed rewards. This decrease of subjective value over time is referred to as temporal discounting. Steep temporal discounting has been shown to be associated with negative outcomes, and interventions that reduce discounting have shown positive welfare effects. Surprisingly, however, very little evidence exists of how temporal preferences arise and which environmental forces shape them. This proposal tests a simple hypothesis of how short-sighted temporal preferences could arise endogenously. Specifically, we hypothesize that poverty leads to stress, stress leads to short-sighted temporal preferences, and short-sighted preferences in turn reinforce poverty. Thus, our proposal seeks to identify a potential micro-mechanism for behavioral change. To establish the generality of this mechanism, we will conduct experiments in both developing and developed countries, both in the laboratory and in the field; we aim to establish causality in all studies, and employ novel measures of welfare (cortisol and cytokines). First, in a laboratory experiment, we ask whether stress has a causal effect on temporal discounting; we induce stress in participants and subsequently measure its effect on temporal discounting. This experiment will reveal whether stress leads to short-sighted decision-making. In the second study, we ask whether poverty causes stress and short-sighted choices. We develop a novel laboratory paradigm that mimics some features of poverty, and then ask a) whether this manipulation increases levels of the stress markers cortisol and alpha-amylase, and b) whether "poorer" people show higher temporal discounting than others. This result would suggest that poverty may cause stress and short-sighted choices. The third study takes place in the field, and in a developing country, and asks for the causal effect of a poverty increase on behavior. We take advantage of a unique natural experiment among the Maasai of Southern Kenya: using rainfall data as an instrumental variable, we can identify the causal effect of an exogenous increase in poverty on stress and temporal discounting. Finally, the fourth study tests the converse question, namely the effects of an exogenous decrease in poverty decreases stress and leads to more far-sighted decision-making. This study will consist of a randomized controlled trial in Kenya, in which randomly selected poor households receive an unconditional cash transfer, free health insurance, or no intervention. Through these exogenous interventions, we can identify the causal effect of poverty alleviation on behavior. Together, these studies will answer whether the candidate mechanism for short-sighted decision-making outlined above withstands causal scrutiny, and thus identify a potential micro-level mechanism for behavioral change. (29 lines)