Running Head

Hindsight Bias 1 of 10 Running Head: HINDSIGHT BIAS: EFFECT OF KNOWING THE OUTCOME BEFOREHAND ON THE PERCEIVED PREDICTABILITY OF EVENT

Hindsight Bias: Effect of Knowing the Outcome Beforehand on the Perceived Predictability of Event Christine Mae G. Olivar University of the Philippines-Diliman

December 10, 2007

Hindsight Bias 6 of 10 Abstract Knowing that an event occurred beforehand increases the perception that the event really is inevitable or more likely to happen. The change in perception happens unconsciously within the individual. This study demonstrated this phenomenon by showing that giving two opposite claims on different individuals would make them accept the claim as if it was predictable.

Hindsight Bias 7 of 10 Hindsight Bias: Effect of Knowing the Outcome Beforehand on the Perceived Predictability of Event Many people blame others or regret their decisions after coming across its consequences. Once they experience the effect of their judgment, they cannot help to think that they might have already seen things coming; they simply should have been better in reading the signs. They think that if only they were more careful or if only they were not pulled in by the other “wrong alternative choices”, they might have done the right thing. They think that they already knew what would happen all along. The I-knew-it-all-along phenomenon usually is observed when people see the result of their choice, whether the result is good or bad. After learning the outcome, they feel that the event was very predictable, even though they were not able to predict it beforehand (Ashcraft, 1989). The event seems less surprising to them than to people asked to guess the outcome (Myers, 1992). This phenomenon has been studied several times and is technically called hindsight bias. Baruch Fischhoff (1975, 1977), the psychologist who started and made a number of studies on hindsight bias, proved that (a) reporting an outcome’s occurrence increases its perceived probability of occurrence; (b) people who have received the outcome knowledge are largely unaware of the change it has done on their perceptions. This study would like to demonstrate this. Myers (1992) said that this could easily be done by giving half the members of a group some purported psychological finding and the other half opposite the result. He also added that people given these opposite results could

Hindsight Bias 6 of 10 easily explain it and would not find the result surprising; however, thinking of it, when opposite statements seems like common sense, there is a problem. That “problem” would be proven in this study in order to show the cognitive bias. Method Participants Sixty undergraduate students from the University of the PhilippinesDiliman who have not taken General Psychology course were randomly selected as participants. Their consent was asked before they underwent the experiment. Design Thirty of the participants were given a questionnaire that claims a certain finding supported psychological study. The participants were asked to rate their surprise in the psychological claim from a 6-point scale (from 0 to 5, 5 being the highest). Their rating of being surprised by the psychological finding would measure the way the perceived the predictability of the said finding. Beyth and Fischhoff said: “The ‘surprisingness’ of a set of events might be defined as the extent to which unlikely events are perceived to occur and likely events not to occur. For a judge evaluating his performance, the “surprisingness” of a set of events is an indicator of his degree of understanding.” Same procedure was done to the other thirty participants except that the claim in their questionnaire is the opposite of the claim in the first group.

Hindsight Bias 7 of 10 One of the questionnaires read: “Recent research in psychology has shown that when selecting mates, people are more likely to prefer those who are similar to them. It appears there is some truth in the saying that birds of a feather flock together.” While the other questionnaire read: “Recent research in psychology has shown that when selecting mates, people are more likely to prefer those who are different from them. It appears there is some truth in the saying that opposites attract.” The means of the perceived level of being surprised would then undergo independent groups t-test to find if their relationship is significant to this study. Procedure Thirty experimenters facilitated the study in an open public area. Each experimenter was assigned to survey two participants that would receive different questionnaires. The distribution of questionnaire on the two participants did not require to be facilitated at the same time. The participant was not informed about the real aim of the study at the start. The experimenters simply introduced themselves and told the participants that they will be participating in a psychological study. But upon getting the data needed from the participant, the experimenter then explain the motive of the study and the process of experiment. The experimenter also cleared that the only real

Hindsight Bias 6 of 10 psychological claim is the one regarding the attraction of similar people. Results With an alpha level of .01, the closeness of values between the mean of the claim on “similar attracts” (M = 1.83, SD = 1.29) and the mean on “opposite attracts” (M = 1.70, SD = 1.24) is statistically significant. As shown in the frequency graph below, very few answered 4 and 5 as the level of their surprise with the said psychological finding. Participants who were surprised by level of 3 on the finding that “similar attracts” is high (mode = 3). Though this may seem to contradict the concept of hindsight bias, result still showed a low mean and 57% of the sample is below the level of 3. It is also observable in the graph that the distribution is concentrated on the left side of the graph.

Level of Surprise 12

Scale

10 8

Similar

6

Opposite

4 2 0 0

1

2

3

Surprise

4

5

Hindsight Bias 7 of 10 Discussion The low value of the “surprisingness” on the two different claims indicates that the sample perceived the event as likely to occur (Beyth & Fischhoff, 1975). If a person looks backward, the person “remembers” attributing a greater likelihood to the event before its occurrence than he actually did attribute to it (Beyth & Fischhoff, 1975). He overestimates both how much he knew (memory) and would have known (hypothetical) without told the answers to general-knowledge questions (Fischhoff, 1977). Thus, overconfidence bias is also connected with hindsight bias. Overconfidence bias is said to exist when individuals are inappropriately confident in their ability to estimate an uncertain quantity (Bazerman, 1990). Consequently, availability, another cognitive bias is said to cause the overconfidence of an individual that he knew the event all along (Restle, 1961). Availability refers to the ease with which an item can be brought to mind as a label for experience (Horrowitz, Noman & Day, 1966: A. Tversky & Kahneman, 1974). Familiar information showed by the event can lead to enormous judgments (Tversky and Kahneman, 1973). The person who had undergone the whole process of change in perception is unaware of it (Fischhoff, 1975). The significant similarity and low values of means on the degree of surprise on the participants show the unconscious change in perception. Beyth and Fischhoff (1975) said that a person may find himself so “anchored” in his present (after) state of mind that his previous state is beyond retrieval. Moreover, the ability to access our previous knowledge state would require significant storage space and would lead to a

Hindsight Bias 6 of 10 memory overload; forgetting may be necessary for memory to maintain its function (Hertwig & Hoffrage, 1999). Forgetting also prevents a person from using old information that may be outdated because of changes in environment (Bjork & Bjork, 1988). Hindsight bias lulls people into believing that our opinions are more accurate than they really are (Judgment and Decision, 1988). This causes them to overlook their misjudgments and mistakes. However, though this bias seems uncontrollable, people can always think if they really knew what would happen all along whenever they say that they knew it all along. References Ashcraft, M. A. (1989). Human memory and cognition. Glenview, Ill. : Scott, Foresman. Beyth, R., & Fischhoff B. (1975). I knew it would happen. Organizational Behavior and Human Performance, 13, 1-16. Bjork, E. L., & Bjork, R. A. (1988). On the adaptive aspects of retrieval failure in autobiographical memory. In M.M. Gruneberg, P. E. Morris, & R. N. Sykes (Eds.), Practical aspects of memory: Current research and issues (Vol II-1, pp.283-286). Chichester, England: John Wiley. Fischhoff, B. (1975). Hindsight ≠ Foresight: The effect of outcome knowledge on judgment under uncertainty. Journal of Experimental Psychology, 1, 288-299. Fischhoff, B. (1977). Perceived informativeness of facts. Journal of Experimental Psychology, 3, 349-358.

Hindsight Bias 7 of 10 Hertwig, R., & Hoffrage, U. (1999). Hindsight bias: A price paying for fast and frugal memory. In G. Gigerenzer, P. M. & the ABC Research Group. Simple heuristics that make us smart (pp. 191-208). New York: Oxford University Press. Myers, D. G. (1992). Psychology. New York : Worth Publishers. Payne, J. W. (1993). The adaptive decision maker. Cambridge: Cambridge University Press. Restle, F. (1961). Psychology of judgment and choice: a theoretical essay. New York: Wiley. Reflection Haay. Field trip no’ng Sabado ‘tsaka Linggo. Tapos tinapos ko lang ‘yong isa pang exercise dito sa 115 no’ng Wednesday. Tapos may tower making challenge kami sa ES no’ng Thursday. Tapos kinabukasan naman, Friday, may exam sa Chem 31. E, kamote na ‘ko do’n, napaaral tuloy ako. E, anak ng tokwa, no’ng nag-exam kami, bagsak pa rin ako. Tsk. Sa madaling salita, naubusan talaga ‘ko ng oras sa paggawa ng paper na ‘to. Hehehe. Alibi mode. Pero di nga, gahol talaga ‘ko sa oras. Kaya no’ng Sabado-Linggong nando’n ako sa required field trip, puro 115 lang ang nakikita ko. Mga taong 115, mga plate number na PSY 115, mga punong hugis 115, mga ibong humuhuni ng 115, pagkaing 115, tubig na 155, hanging 115, lahat 115. Hehehe. Internalized ko na talaga ‘yong 115,

e.

Pero,

kahit

ganito,

natuwa

naman

ako

sa

proseso

nitong

pagsusulat ko dito. Kakaiba ‘yong pakiramdam na makahagilap ng isang gintong journal article. ‘Yong tipong ‘yong original na promotor ng isang sikat na study, e, nahukay mo sa baul ng library. Uubo-ubo ka pa habang nag-iingat na baka biglang madurog at maging alikabok ‘yong

Hindsight Bias 6 of 10 libro dahil sa kalumaan. Saya talaga. Kaso, namroblema ako nang ang dami-dami ko nang sources. Di ko alam kung pa’no i-organize ‘yong ideya,

e.

kailangan

Tapos

no’ng

kinokompyut

kong

baligtarin

‘yong

ko

‘yong

alpha

significance

level,

pa’no

sa

SPSS,

ang

null

hypothesis, e, dapat hindi pareho ‘yong means, kaya dapat .95 ‘yong alpha

level.

Hindi

ko

alam

kung

pa’no

gawin

‘yon

sa

SPSS,

e.

Napavisual basic pa ‘ko sa loob ng SPSS. Anak ng tokwa. Kaya tagal ko nagsearch

kung

pa’no

mapapabilis

‘yong

pagkokompyut.

Kulang

naman

‘yong data ng book ko sa 110 para sa mga critical t ‘tsaka ‘yong values ng non-directional kung sakaling manu-mano. Buti na lang may applet sa internet na nakakakompyut. At ayun, with an alpha level of .01 the study is significant. Yey. Bale ngayon, late ako magpapasa. Sakto alas singko. Di ‘ko pa napiprint. Sarado na ang department. Hehe. Parang alibi lang talaga.