【正文】 lieve, discard, or downgrade the corresponding weightings for data that appear to conflict with those expectations.[27] ? Falseconsensus effect the tendency of a person to overestimate how much other people agree with him or her. ? Functional fixedness limits a person to using an object only in the way it is traditionally used ? Focusing effect – the tendency to place too much importance on one aspect of an event。 期望效用理論 ? 卡尼曼和特沃斯基 (1986)認為，事實上兩種方法都是必需的： 期望效用理論描繪了理性行為的特征；而前景理論則描述了有限理性人的實際行為 。 ? 由確定性到不確定性的變化給人感覺的效力很大：比如，由 p=p= 10%的變化給人感覺的效力很大。 系數(shù) λ1表示損失區(qū)域比收益區(qū)域更陡的特征。 四、 框架效應 (Framing effects) ? “亞洲疾病問題”實驗 ：想象美國正準備對付一種罕見的亞洲疾病，預計該疾病的發(fā)作將導致 600人死亡。 ?現(xiàn)在，考慮下面只有一個階段的兩個博彩： ?博彩 C： 20%的機會得到 4000元； ?博彩 D： 25%的機會得到 3000元。 ? 在第一個實驗中 (A/B)，隱含的財富參考點是 0。 ?博彩 B： 50%可能性贏得 2023元， 50%可能性什么也得不到。 一、確定效果 (certainty effect) ? 1）在下面兩個博彩間進行選擇： ? 博彩 A： 33%的機會得到 2500元， 66%的機會得到2400元， 1%的機會什么也得不到； ? 博彩 B： 100%的機會得到 2400元。 ? 在確定的損失和“賭一把”之間，做一個抉擇，多數(shù)人會選擇“賭一把”。編輯階段之后，決策者對期望進行估值并進行選擇。 ? (5)允許決策權重隨得益的等級和跡象變化，這是對 SWU的進一步發(fā)展。那么，該隨機變量給他的效用便是： EU理論的質疑 ? EU理論及 SEU理論描述了 “理性人” 在風險條件下的決策行為。假設一個缸中有 100個球，其中 33個球為紅色，其余 67個為黑色或黃色，你若從中拿出一個球： ? 博彩 A：若球為紅色，你得到 1000元； ? 博彩 B：若球為黑色，你得到 1000元。 ? 第二組賭局： ? 賭局 C： 11％的機會得到 100萬元， 89％的機會什么也得不到。實驗中，被試者被要求在兩組彩票組合中分別進行選擇。（即人的效用函數(shù)往往低估一些只具有可能性的結果，而相對 高估 確定性的結果。 EU理論認為， 假如決策者選擇風險決策備擇方案的過程符合效用公理，那么他一定是選擇預期效用值最大的那項備擇方案。該類模型的特點是針對同結果效應和同比率效應等，放松期望效用函數(shù)的線性特征，或對公理化假設進行重新表述，模型將用概率三角形表示的期望效用函數(shù)線性特征的無差異曲線，擴展成體現(xiàn)局部線性近似的扇行展開。 前景理論 (Prospect Theory, PT) ( 0) 0 , ( 1 ) 1?? ??價值函數(shù) v(x) (value function) 決策權函數(shù) π(p) (decision weight function) 前景理論 (Prospect Theory, PT) ? Kahneman和 Tversky（ 1979）認為，個人風險條件下的決策過程分為兩個階段： ? 第一階段：編輯階段 。 確定效應 損失規(guī)避 參照依賴 反射效應 迷戀小概率事件 前景理論 PT理論的基本原理 PT理論的基本原理 ? 在《賭客信條》一書中，作者孫惟微將前景理論歸納為 5句話： ? “二鳥在林，不如一鳥在手”，在確定的收益和“賭一把”之間，多數(shù)人會選擇確定的好處。稱之為 “迷戀小概率事件” 。根據(jù)期望效用理論有： U(C) U(D)。這說明人是風險偏好的，理由如下： U(C)U(D)，可得： U(1000) (0)+(2023) ?當行動結果是受益時，行為人是風險規(guī)避者；而當行動結果是損失時，行為人是風險偏好者，這個稱為反射效果。 ? 博彩 D： 50%可能性損失 2023元， 50%可能性什么也不損失。 ? 好心人開始很納悶，后來突然醒悟，就沖著快要下沉的吝嗇鬼大喊“我把手給你，你快抓住我！”，這吝嗇鬼一下就抓住了這個好心人的手。 （ 28%） ? 情景二：對第二組被試（ N=155）敘述同樣的情景，同時將解決方案改為 C和 D： ? 如果采用 C方案， 400人將死去。 A B C D 決策權函數(shù) (Decision Weight Function) ( 0) 0 , ( 1 ) 1?? ???1. ()1p p pp ??????當 接 近 0 時 ,當 接 近 時 , (p)p(p)+ (1p) 1?2. ????? 1)]1([ iiiipppp???）（?Kahneman和 Tversky(1979)給出的決策權函數(shù)的形式如下： 決策權函數(shù) π(p) 具有“確定性效應 (certainty effect) ? 期望效用理論 (EU) 認為 ：某一事件的概率 1個百分點的增量，應該對結果的權重具有同樣的影響，無論最初的概率是 0%，41%還是 99%。 ? 決策權重函數(shù)具有以下特點： ? （ 1）決策權重不是概率，它并不符合概率公理。s choices as better than they actually were.[13] ? Clustering illusion – the tendency to overexpect small runs, streaks or clusters in large samples of random data ? Confirmation bias – the tendency to search for or interpret information or memories in a way that confirms one39。s own strong partisan views. ? Hothand fallacy The hothand fallacy (also known as the hot hand phenomenon or hot hand) is the fallacious belief that a person who has experienced success has a greater chance of further success in additional attempts ? Hyperbolic discounting – the tendency for people to have a stronger preference for more immediate payoffs relative to later payoffs, where the tendency increases the closer to the present both payoffs are.[34] Also known as current moment bias, presentbias, and related to Dynamic inconsistency. ? Illusion of control – the tendency to overestimate one39。t because of their lack of visibility. ? Texas sharpshooter fallacy pieces of information that have no relationship to one another are called out for their similarities, and that similarity is used for claiming the existence of a pattern. ? Timesaving bias – underestimations of the time that could be saved (or lost) when increasing (or decreasing) from a relatively low speed and overestimations of the time that could be saved (or lost) when increasing (or decreasing) from a relatively high speed. ? Unit bias – the tendency to want to finish a given unit of a task or an item. Strong effects on the consumption of food in particular.[58] ? Well travelled road effect – underestimation of the duration taken to traverse ofttraveled routes and overestimation of the duration taken to traverse less familiar routes. ? Zerorisk bias – preference for reducing a small risk to zero over a greater reduction in a larger risk. ? Zerosum heuristic – Intuitively judging a situation to be zerosum (., that gains and losses are correlated). Derives from the zerosum game in game theory, where wins and losses sum to zero.[59][60] The frequency with which this bias occurs may be related to the social dominance orientation personality factor. Social biases (1/3) ? Actorobserver bias – the tendency for explanations of other individuals39。s future selves) share one39。s own behaviors to do the opposite (that is, to overemphasize the influence of our situation and underemphasize the influence of our own personality). ? Defensive attribution hypothesis – defensive attributions are made when individuals witness or learn of a mishap happening to another person. In these situations, attributions of responsibility to the victim or harmdoer for the mishap will depend upon the severity of the outes of the mishap and the level of personal and situational similarity between the individual and victim. More responsibility will be attributed to the harmdoer as the oute bees more severe, and as personal or situational similarity decreases. ? Dunning–Kruger effect an effect in which inpetent people fail to realise they are inpetent because they lack the skill to distinguish be