利他偏好的内生模型及其经济学解释

利他行为对自利人性假设的挑战，要求经济学必须把偏好进行内生化处理。笔者首先构建了一个利他偏好内生模型，使得人类行为统一于效用最大化模式并具有了内在一致的规律性和可预测性；然后对利他偏好内生模型的合理性进行了解释。笔者认为，与利己行为不同，行为主体不是从利他行为后果而是从利他行为本身获得效用；通过整体间的生存适应性补偿机制，利他者不仅可以战胜利己者得以存在和持续，而且利他惩罚行为还为人类走出囚徒困境提供了有力的保证。     

辛普森悖论与利他行为的进化

利他行为是自然界和人类社会中广泛存在的现象。但长期以来人们无法解释对行为者本身不利的利他行为如何能避免在自然选择中被淘汰。群体选择理论对此提出了一个解释,即尽管由于利他者相对于利己者处于不利的位置,利他者在每一个群体中的频率都会下降,但利他者在总体中的频率却有可能上升。这种看似不可能的现象被称为辛普森悖论。通过对辛普森悖论的阐述,建立了一个群体选择模型,运用模型的结果对正处于社会转型期的我国片面注重个体利益,忽视集体利益的现状进行了分析。     

利他行为的“道德人”分析

人们普遍认为，利他主义有三种表现形式：即亲缘利他、互惠利他和纯粹利他；而人的行为动机有两种：利己和利他。单纯从利己动机来各种解释利他行为存在着贫困性，引入“道德人”概念则可以对动机上无论是利己还是利他的利他行为有一个统一的解释。     

"经济人"利他行为的经济分析

对于利他行为,许多学者往往将它与利己行为分割开来进行分析,而且很少引入成本收益分析.事实上,利他行为和利己行为都是内部动机的一种偏好体现.本文通过引入利他主义参数和成本收益,提出了一个关于理性经济人的利他行为经济模型,并借助该模型对利他行为进行了符合理性的经济分析.     

作为内生偏好的利他行为及其经济学意义

现代经济学与现代生物学对人性的看法相当一致,都把自利看作人类行为的基本前提。但来自桑塔费学派的最新研究证明,在人类进化的早期阶段,利他行为作为社会规范内部化的产物,在维持个人之间的合作劳动、有效提高族群生存竞争能力方面,具有不可替代的重要作用。我们在ESS(即“进化稳定策略”)基础上提出一个演化均衡模型,进一步解释了利他行为的进化优势以及合作剩余导致利他偏好内生的机制。     

家庭财富的转移效用

家庭财富转移是非常重要的经济现象，是我国农村养老保障的主要形式。本文采用贝克尔(Gary S．Becker)式经济分析方法，建立了家庭利他模型，探讨了家庭财富转移的效用。结果表明，在家庭中，愿意将自身财富转移给他人的利他行为比只考虑自身财富增加而不考虑对他人转移的利己行为更能增加自身效用。     

利他行为及其经济学意义——兼与叶航等探讨

本文指出了叶航(2005)和叶航、汪丁丁、罗卫东(2005)建立的“利他行为演化均衡”模型的错误,重新梳理了利他行为与经济学的关系。现代经济学的分析框架并不排斥利他偏好,利他行为难以进入经济学实证分析,主要是由于利他行为难以量化。人类利他行为是生物进化和社会发展的综合产物,道德情感和道德规范在其中起了关键性的作用,但这并不妨碍经济学把利他偏好当作人性的一部分。经济学可以通过解释道德情感的进化根源、道德规范的形成机制以及道德规范对个人行为方式的影响,来解释人为什么有利他行为。     

利他行为的经济学研究新进展

人们的利他行为是存在且普遍的,对提高效用具有显著作用。研究利他行为不仅具有一定的学术价值,还对政策制定有指导意义。梳理近年来与利他行为动机、理论和实证相关的研究发现：动机上,行为经济学者直接利用被试在现实生活中的社交网络来探讨人们利他行为的动机,区分了普遍利他动机、针对特定人群的定向利他动机和未来互惠动机。理论上,基于复杂社会网络的研究打破了简单模型的局限,加深了对利他行为的理解。实证上,学者们在慈善捐赠、公共品提供、社会规范、利他行为人等方面对利他行为做了大量分析。综合而言,后续研究可从利他行为与社会网络动态变化的关系、实证与理论结合、中国情景下的探讨、解释现实问题等方面拓展。     

产权信念及其对公平偏好与自利偏好的挤出

传统经济理论将产权作为经济绩效的外生变量,但是人类社会的演化路径表明产权是内生于人类族群的共同信念,它与内置于人类心智的公平偏好交互作用影响个体的决策行为。文章运用比较制度实验方法针对不同来源的产权考察其认同信念及其对公平偏好的影响。实验发现,产权不仅导致提议者对回应者和接受者有产权认同信念,也导致提议者的自利偏好和回应者的公平偏好被挤出;通过对利他偏好、策略行为和第三方评价的分离,测度了产权信念;提议者没有强烈的公平偏好动机,而是通过策略行为来最大化自身利益。     

经济学理性的层次与界阈

传统的经济学理性是点理性,容易陷入非此即彼的极端——要么是理性的,要么是非理性的。如此,便丝毫不能容纳利他行为,除非将利他行为纳入利己框架中,而用利己统一利他又备受垢病。本文的分析表明,经济学理性是层次理性,是区间理性。传统经济学理性假定是初级层次的,其内涵必须随社会进步予以拓宽;中级层次的理性行为的下限是利己不损人,上限取决于一个社会公认的道德境界。利他行为并非如传统经济学所认为的不理性,它是高级层次的理性。     

An economic theory of altruism based on rankings in a stable social hierarchy

In order to fully understand the interaction between selfish and non-selfish actors, social scientists need rigorous formal models of other-regarding preferences. While the current models clearly present progress relative to the self-interest approach, the evidence also makes it clear that further theoretical progress is warranted. There is ample opportunity for improving our understanding of other-regarding behavior. This paper develops a theory of economic altruism entirely compatible with self-interest utility maximization by rational individuals. Sympathy arises when someone is interested in improving somebody else’s condition, and this will also enhance the utility of the one who acts. Construed in that way, sympathetic behavior is essentially self-interested behavior. A question addressed in this paper is whether a sympathetic population of individuals will exert their income-producing labor differently than a population of egoistic individuals. Two parameters suffice to characterize the altruistic conduct of an individual: a parameter governing the individual’s ranking in a social hierarchy and a parameter determining the sensitivity of an individual’s sympathy for others at different social ranks. The main testable implication of the theory is that in a large population, where each individual has a concave utility function embodying sympathy, the altruistic behavior of any specific individual is determined by his rank in the social hierarchy. A second implication is that in a horizontal social hierarchy, the most altruistic people in the population are those in the middle of it.     

Altruism and Spite in a Selfish Gene Model of Endogenous Preferences

Economists and biologists have long grappled with the apparent contradiction of altruism in a naturally-selected world. Standard economic models are built upon an assumption of material self-interest where agents maximize individual outcomes without regard for the effects on others. This paper begins with a brief discussion of the evidence that human behavior deviates from the economic assumption. With the goal of more accurately describing human nature, the interpersonal components of preferences are derived in a genetic model. This model predicts a variety of behaviors that are considered paradoxical within the standard economic framework. The optimal attitude towards others is parameterized by the genetic relationship between individuals and by the population size. For interactions between ‘average’ individuals, the standard economic assumption is the limiting case of the genetic model as the population becomes arbitrarily large. This revised version was published online in August 2006 with corrections to the Cover Date.     

Socialization and altruism

An important problem in theoretical biology is to explain how altruism can have positive selection value. We model socialization as a costly public good that raises altruism and we study evolution equations for altruistic preferences. Stable cultural (social) equilibria exist in which socialization is supplied privately and property rights exist without civil government. In equilibrium, agents are altruistic in ways not explained by traditional biological theories. The theory essentially formalizes the story in Adam Smith'sTheory of Moral Sentiments.     

Economic growth and endogenous intergenerational altruism

The recent literature on the endogenous formation of preferences has emphasized that while some preferences are more conducive to growth than others, economic growth also contributes to the formation of particular tastes [Becker, Gary S. (1996): Accounting for Tastes, Cambridge, Ma.: Harvard University Press]. In this paper, we construct a neoclassical growth model where intergenerational altruism can be endogenously reinforced and entails costly sacrifices on the part of parents to acquire such trait. While the incentives to acquire altruistic traits depend on the economic conditions, in turn altruism determines the level of intergenerational bequests and ultimately the pace of capital accumulation and economic growth. It is shown that intergenerational transfers are driven by a natural degree of altruism at earlier stages of economic growth. Once individuals have satisfied their own physiological constraint in the course of economic development, they devote resources to shaping their altruistic preferences, increasing their social degree of altruism above its natural level. This in turn increases the share of intergenerational transfers and speeds up economic growth.     

In search of the good samaritan: estimating the impact of ‘altruism’ on voters' preferences

This paper continues the development of a theoretical foundation for measuring ‘altruistic’ behaviour with respect to tax versus expenditure preferences in three specific spheres: health, education and welfare payments. Particular emphasis is placed on analysing the choice theoretic calculus that underlies individual preferences. Using this theoretical foundation, econometric techniques allow progress to be made in measuring the characteristics of the underlying utility function. The empirical work relates to the UK and confirms that both self-interest and public interest (with a slight emphasis on the latter) determine overall preferences. The implications of this for the public choice school are then examined.     

What motivates common pool resource users? Experimental evidence from the field

This paper develops and tests several models of pure Nash strategies of individuals who extract from a common pool resource when they are motivated by a combination of self-interest and preferences for altruism, reciprocity, inequity aversion, or conformity. Using data from experiments conducted in three regions of Colombia that depend critically on a local fishery, we test whether an econometric summary of the subjects’ pure Nash strategies is consistent with one or more of these models. We find that a model that balances self-interest with a strong preference for conformity best describes average strategies.     

Measuring altruism in a public goods experiment: a comparison of U.S. and Czech subjects

This paper compares contributions to an experimental public good across the United States and Czech Republic, using a design that allows us to distinguish between altruism and decision error. Czech subjects contribute significantly more than American subjects, and further analysis reveals that this result cannot be attributed to the confounding effects of gender or decision error. Instead, preferences for altruism appear to differ across groups: Czechs are more altruistic than Americans and men are more altruistic than women.     

Optimal contracting with altruism and reciprocity

Motivated by the recent experimental evidence on altruistic behavior, we study a simple principal–agent model where each player cares about other players' utility, and may reciprocate their attitude towards him. We show that, relative to the selfish benchmark, efficiency improves when players are altruistic. Nevertheless, in contrast to what may be expected, an increase in the degree of the agent's altruism as well as a more reciprocal behavior by players has ambiguous effects on efficiency. We also consider the effects of the presence of spiteful players and discuss how monetary transfers between players depend on their degrees of altruism and spitefulness.     

Are benevolent dictators altruistic in groups? A within-subject design

We use a within-subject experimental design to investigate whether systematic relationships exist across distinct features of individual preferences: altruism in a two-person context, risk aversion in monetary outcomes, and social preferences in a group context. We find that altruism is related to demographic variables, including years of education, gender, and age. Perhaps most importantly, self allocation in a two-person dictator game is related to social preferences in a group context. Participants who are more generous in a dictator game are more likely to vote against their self-interest in a group tax redistribution game which we interpret to be an expression of social preferences.