作者:Ah sa 发表时间:2001年7月26日 20:57
为什么某些人愿意捐钱给某类慈善事业?
作者:DNKM 发表时间:2001年7月27日 11:26
如果说人性使然等于什么也没有说。但如果不这样说，题目太宽泛，Ah sa能否细化，给个场景？
作者:光头 发表时间:2001年7月27日 11:32
经济学的范围是什么？有没有范围？
据说经济学要实行经济霸权主义，用经济学来解释一切。有这个必要吗？我用哲学、心理学也可以解释一切。
作者:DNKM 发表时间:2001年7月27日 13:46
如果经济学能够解释一切，至少不是件坏事。
奈特有言：经济学就是经济学家研究的东西
作者:光头 发表时间:2001年7月27日 18:32
经济学就是经济学家研究的东西——奈特是不是中国的一个老和尚的说？呵呵。
作者:DNKM 发表时间:2001年7月27日 19:07
虽然奈特说的话是一种同义反复，但从经济学不断扩大的疆域、尤其是由著名经济学家扩展的领域看，这句话意味深长。
作者:phoenixsoar 发表时间:2001年7月27日 21:08
别跑题了。一个经济学帝国主义的解释是：捐献产生的满足被纳入个人效用函数之中。更宽泛的说，这是效用理论对利他行为的一般解释模式。
作者:DNKM 发表时间:2001年7月27日 21:15
:phoenixsoar：
但是我不得不说，你什么也没有解释。我们还是回到了假设，我们能够给假设一个解释吗？
作者:Ah sa 发表时间:2001年7月27日 22:01
经济分析基于某种偏好假设是可以的(例如我们假设人爱吃苹果多于石头),但解释的现象不应单只是偏好假设的直接含义(immediate implication),否则是explanation by assumption。如将"捐献"纳入个人效用函数之中,用来解释"捐献现象"就是explanation by assumption。比较好的假设是将别人的效用纳入我个人的效用函数之中(即"利他" altruism),因为"捐献现象"不是这偏好假设的直接含义。
"捐献问题"的有趣处是:
即使假设我关心他人的幸福,但是我的预算有限,如果别人愿意捐钱,我的最好策略是free-riding.
作者:oscarwong 发表时间:2001年7月29日 01:29
我想到有三个原因.
1.可以扣税.以此来作解释,可以进一步说出较富有的人为什么比较穷困的人更乐于做善事.在可扣税的情况下,富人捐钱的机会成本大大减低.甚至是没有成本的.捐钱是特定税收制度下的极大化行为.
2.另一个原因比较适合用来解释教徒捐钱的行为.就是如果教徒不作出一定的捐献的话.教徒是会受到上主一定的惩罚的.惩罚可能来自个人心理上的不安,也有的是来自其它教徒的歧视.即便是有较爱心的教会,也会在一定情况下排拆那些不愿付出的教徒.以防止free-riding.的情况过份在教会出现.基于这些原因,教徒还是会损钱来支持慈善事业.如果细心观察,则会发现教徒的捐钱也会出现某类形的偏好.比如会只捐钱给自己所参与的教会中.而对其它教会则很少理会.如很少基督教徒会对佛教进行捐钱.因此类捐钱不会对教徒做成任何有效用的满足.甚至,被其它教徒知道后,还会出现一定的负效用.
3.捐钱其实不是慈善性质的.只是交易的其中一种方式.政治捐献皆属此类.
总括来说,捐钱其实大致上是一种理性行为.然现实总是千奇百怪的.且确实也有些捐钱行为是无法用理性行为的假设来解释的.果尔,亦有不少人开始用非理性的行为来解释此类现象.行为经济学便是其中之一.
作者:Ah sa 发表时间:2001年7月30日 07:43
但现实中,好像仍有许多人不为税务,信仰,政治上的目的,十元百元的捐给慈善,这十元百元对整个慈善事业微不足道,即使我关心他人的幸福,但如果别人愿意捐钱,我大可free-ride一下,坐享其成
作者:DNKM 发表时间:2001年7月30日 08:55
Ah sa,如果我不把捐献行为放入效用函数，并且除了把他人的效用放入外，再放入一个声誉如何？
作者:Ah sa 发表时间:2001年7月30日 11:01
是的,"沽名钓誉"模型能解释捐钱开办"XXX纪念学校"等行为,但我比较感兴趣的是那些匿名捐钱,或在街上捐十元八块给"红十字会"等(没明显回报的)行为
作者:Ah sa 发表时间:2001年7月30日 11:17
I.Lo 刚刚告诉了我一个好例子:捐血
作者:oscarwong 发表时间:2001年7月30日 13:19
是的,"沽名钓誉"模型能解释捐钱开办"XXX纪念学校"等行为,但我比较感兴趣的是那些匿名捐钱,或在街上捐十元八块给"红十字会"等(没明显回报的)行为
re:用free-riding实确可解释这种行为.不过,要了解,free-rider并不是白痴或没脑筋的人
free-rider的行为模式可用下面的情形来描述.
1.free-rider一般其实很关心或留意其它人的付出行为,因其它人的行为或付出与否,直接影响自己的利益.或可先假定free-rider是会关心某境环中所出现的总福利水平.(我的想法是free-rider也有好几个不同的类别.而现在我所假定的一种是会试图去影响其它人作出更多付出的一种free-rider)
2..当free-rider知觉到在所处身的环境中其它大部份人均会捐钱的时候,最优的行为策略不是坐享其成,然后「侧侧膀,唔多觉」,任由其它人努力.用捐钱来做例子,free-rider一般的最优策略不是不作捐钱,而是自己捐献了一元或很少的数目,然后大加宣传,再叫其它人齐齐努力捐钱.每人做好捐上数百数千元.这种行为模式可称为「沽名钓誉」模式.free-rider从这种模式中得到的好处不是从中得到有多少名声.而是可以用较少的努力来影响其它人为自己的福利做更多的付出.正是人出饭菜,我出鼓油.
3.若情况有异,free-rider知觉到所处身的环增中,其它大部份人都不付出的时候.则会用随机的方式作出一二十元的小捐献的.因其它大部份人皆不付出的情况下,最优的策略是不知道的.因我捐钱时无法得其它其它人会不会是和我是同一类的free-rider.但比较起前一种情况,这时free-rider会更有动机去影响其它人捐钱.
若上述的分析是可以接受的话,则我们可用此来解释人们为什么在没有明显回补的情况下也会用金钱或行动支接慈善事业.我的看法是,若free-rider是关心其它人的付出与否,则free-rder一般不会对其它人的付出行为坐视不理的.并且会试图去影响其它人的提供更多的付出.如此,我会把日常生活中出现的小捐献解释为free-rider影响其它人进一步付出的策略行为.
作者:Ah sa 发表时间:2001年8月1日 15:19
oscarwong 的建议和我心中想法接近: 捐小小钱来显示我这"有心人"的存在,在动态模型中,这小小信号对慈善事业长期发展影响可以非常巨大.
但这模型需要某些技术假定(e.g. uncertainty of people's type and dicrete charity fund),详情以后再谈.
作者:bear 发表时间:2001年8月1日 21:09
做任何事怎么可能没有回报呢？有人喜欢被打，他被打时的快乐就是回报。捐钱者的动机为何对解释他的行为不重要，oscarwong 指出的第一第三点才是正路。第二点若能指出歧视的行为或可以观察的结果就更对路了。现在要想想，什么情况下，捐钱的行为有变，例如，捐的次数多了，每次捐的数目大了，捐的对象多了，捐钱的对象变了，等等。这些情况，就是局限了。例如：当一个每月收到请求帮助非洲灾民的信件多了，他每月捐钱的数目就增加了，诸如此类的。
捐钱什么时候会是不理性的？这是在说，在同样的环境下，这个人或者捐钱或者不捐，或者捐多或者捐少，或者捐给A或者捐给B。真是这样，经济学无能为力。GARY BECKER不信人一时理性一时不理性，我也不信。给我一个实例看看。谁的行为完全随机？ALCHAIN说，一开始人人都随机都不要紧，结果生存下来的那些随机的幸运者，其行为也是符合经济学中理性的假设。
作者:phoenixsoar 发表时间:2001年8月15日 19:28
oscarwong,Ah sa,bear三位说的有道理，一个关于搭便车者的沽名钓誉模型能较好的解释小数额捐赠。但是，对于数额较大的捐赠行为，沽名模型便难以解释了。如bill gates声称要将其遗产全部捐赠，在这里假设不存在欺骗行为（空头承诺），他这样做是因为收益驱动吗？但是不管如何，声誉（他人对捐赠者的支付），受捐赠者从捐赠中得到的效用，都应纳入捐赠者的个人效用函数中。集体行动的逻辑也相当重要。请各位指教。
作者:VC 发表时间:2001年8月16日 17:23
我对街头买艺者产生了怜悯之心，给了一些钱。
这只能从宗教方面解释了。
作者:DNKM 发表时间:2002年3月29日 13:16
（转贴）
Deviations from the mean
Mar 21st 2002
From The Economist print edition
Biologists are helping economists to explain why humans are not always selfish
AT SOME point during their education, biology students are told about a conversation in a pub that took place over 50 years ago. J.B.S. Haldane, a British geneticist, was asked whether he would lay down his life for his country. After doing a quick calculation on the back of a napkin, he said he would do so for two brothers or eight cousins. In other words, he would die to protect the equivalent of his genetic contribution to the next generation.
The theory of kin selection—the idea that animals can pass on their genes by helping their close relatives—is biology's explanation for seemingly altruistic acts. An individual carrying genes that promote altruism might be expected to die younger than one with “selfish” genes, and thus to have a reduced contribution to the next generation's genetic pool. But if the same individual acts altruistically to protect its relatives, genes for altruistic behaviour might nevertheless propagate.
Acts of apparent altruism to non-relatives can also be explained away, in what has become a cottage industry within biology. An animal might care for the offspring of another that it is unrelated to because it hopes to obtain the same benefits for itself later on (a phenomenon known as reciprocal altruism). The hunter who generously shares his spoils with others may be doing so in order to signal his superior status to females, and ultimately boost his breeding success. These apparently selfless acts are therefore disguised acts of self-interest.
All of these examples fit economists' arguments that Homo sapiens is also Homo economicus—maximising something that economists call utility, and biologists fitness. But there is a residuum of human activity that defies such explanations: people contribute to charities for the homeless, return lost wallets, do voluntary work and tip waiters in restaurants to which they do not plan to return. Both economic rationalism and natural selection offer few explanations for such random acts of kindness. Nor can they easily explain the opposite: spiteful behaviour, when someone harms his own interest in order to damage that of another. But people are now trying to find answers.
Good for you, good for me
The favoured tools for exploring seemingly odd behaviours are called public-goods experiments and ultimatum games. In a public-goods experiment, each member of a group of subjects is given a financial stake and asked to use this money to contribute to a common pool. This pool is then expanded by the experimenters and redistributed to individuals in the group.
One recent public-goods experiment was conducted by Ernst Fehr from the University of Zurich and Simon G?chter at the University of St Gallen in Switzerland. Sets of four students were given around $20 to participate in a group project. They were told that they could keep any money they did not invest. The rules of the game were that every $1 invested would yield $1.60, but that these proceeds would be distributed to all group members—in other words everyone would get 40 cents. Thus if everyone invested, each would walk away with $32, and the public good would have been served. If, however, only one person invested, that sucker would take home a mere $8.
The experiment was run first as a series of six rounds in which the participants were anonymous, investment decisions were taken simultaneously, and no two participants interacted more than once. At the end of each round, each player was told how other members of the group had invested and what the individual pay-offs would be. In this version of the game, people quickly learned not to invest. By the sixth round, contributions to the pool had dwindled to nothing.
The second version of the experiment, though, gave the individuals the opportunity to punish each other financially at the end of each investment round. At a cost of $1, a group member could anonymously fine another $3. Of the 240 participants in the experiment, 84% punished at least once and around 9% punished more than ten times. Most punishment was imposed by above-average contributors (deemed co-operators) on below-average contributors (deemed defectors or free-riders). Punishment was related to notions of fairness; the amount of punishment given was directly related to how far a free-rider's contributions deviated from the group's average. And punishment had an effect. It substantially increased the amount that was invested in the public good: more than 90% of the participants contributed more money when punishment was a possibility.
These punishments might look spiteful. In fact, they were altruistic. This is because, at the end of each investment round, the participants were swapped between groups so they would never invest with the same people again. Participants were therefore paying to punish someone with whom they would not interact again. Altruism, in other words, emerged in the second form of the game, as punishment, but not in the first.
The idea that people sometimes value “fairness” over personal gain was also suggested by an ultimatum game run last year by Joseph Henrich, an anthropologist at the University of Michigan's business school, and his colleagues. In an ultimatum game, a participant is given what is for him the equivalent of a day's wages, and asked to contribute a portion of this to a second, anonymous person whom he will never meet again. The recipient can accept or reject this offer, but if he rejects it, neither party receives any money.
The logic behind an ultimatum game suggests that, if people wish to maximise their resources, as standard economics assumes, a recipient will accept any offer made by a donor. Conversely, the donor will always offer as little as possible. But that is not how things turn out. Offers are guided by notions of what is fair, as are rejections. The researchers found that offers ranged from 22% to 58%, and offers higher than 50% were sometimes rejected.
This evidence and the findings of public-goods experiments led the anthropologists to conclude that acceptance and rejection were strongly linked to feelings of fairness and reciprocity in addition to material benefits. People reward those who act in a co-operative manner and punish those who do not—even if such behaviour costs them something personally.
That is, of course, only a scientific confirmation of a human commonplace. And when a new phenomenon is recognised by science, a name always helps. In a forthcoming paper in Human Nature, Dr Fehr and his colleagues argue for a behavioural propensity they call “strong reciprocity”. This name is intended to distinguish it from reciprocal altruism. According to Dr Fehr, a person is a strong reciprocator if he is willing to sacrifice resources to be kind to those who are being kind, and to punish those who are being unkind. Significantly, strong reciprocators will behave this way even if doing so provides no prospect of material rewards in the future.
Turn and face the change
That does not, of course, explain how strong reciprocity evolved in the first place. The modern theory of natural selection sees the process working on individuals: if you are “selected out” (ie, killed), your genes cannot contribute to the next generation. Most selective pressures (predators, sexual competitors and so on) work at the individual level. Those that might wipe out whole groups at a time, such as infectious diseases, are not susceptible to collective action, so might as well be individual pressures. However, if what kills individuals frequently kills entire groups, but is something that collective action might successfully combat, the unit of selection might become the group. In the case of human beings, who (thanks to language) can collaborate in detail, a wide range of group-threatening risks—wars, famine, environmental catastrophes and so on—might be susceptible to such collective action. Groups containing strong reciprocators might be better adapted to survive, particularly since their behaviour coerces even the selfish into action that favours the common good. Genes for strong reciprocity would thus spread.
The idea of strong reciprocity explains both previously inexplicable altruistic acts and the existence of spite. That makes it theoretically attractive. Its boosters also think that it might have practical applications. A pair of economists, Samuel Bowles at the Santa Fe Institute in New Mexico and Herbert Gintis of the University of Massachusetts in Amherst, has suggested that if policymakers want to achieve certain public goods, such as the sharing of common resources, it might be useful to provide opportunities for the public-spirited to punish the free-riders in society. This kind of thing works in small fishing communities, where free-riders are punished by social exclusion. Extending these sorts of penalties to society at large could pit the better side of human nature against its other half, and make things better for everyone.
作者:piont 发表时间:2002年3月29日 15:16
比尔（或任意一个阔佬），发誓将其遗产悉数充公，有以下动机：
1，为其后代设下硬预算约束，以促其努力奋斗。这实际上是和其子孙博弈的结果。可以简单模型表述。
2，获得社会对其财富合法性的确认，有利于长远发展。
3，对其产业的推销。
参阅：http://bbs.efnchina.com/dispbbs.asp?boardID=92507&ID=28517
