Optimistic Bias

Some quotes on optimistic bias, taken from David A. Armor and Shelley E. Taylor (2002) “When Predictions Fail: The Dilemma of Unrealistic Optimism” in Thomas Gilovich (et al.) (Eds.) Heuristics and Biases: The Psychology of Intuitive Judgement:

  • “Students expect to receive higher scores on exams, at least when those exams are still some time away, then they actually receive.” (Shepperd, Ouellette and Fernandez (1996))
  • “Most people expect they have a better-then-average chance of living long, healthy lives; being successfully employed and happily married; and avoiding a variety of unwanted experiences such as being robbed and assaulted, injured in an automobile accident, or experiencing health problems.” (Weinstein (1980))
  • Professional financial analysts “were reasonably able to anticipate periods of growth and decline in corporate earnings, but consistently overestimated earnings realised.” (Calderon (1993))
  • Newlyweds “almost uniformly expect that their marriages will endure a lifetime” despite the large proportion of marriages that end in divorce. (Baker and Emery (1993))
  • Vacationers “anticipate greater enjoyment during upcoming trips than they actually expressed during their trips.” (Mitchell, Thompson, Peterson and Cronk (1997))
  • “People expect to complete personal projects in less time than it actually takes to complete them” (Buehler, Griffin & Ross (1994)) (“Planning Fallacy” / “Hofstadter’s Law”)
  • “Second-year MBA students were found to overestimate the number of job offers they would receive, the magnitude of their starting salary, and how early they would receive their first offer.” (Hoch (1985))
  • Students “consistently reported that they would behave in more socially desirable ways – for example, that they would be more resistant to unwanted social influence, or more likely to donate time to a worthy charity – than did people who have not first been asked to make predictions about their behaviour”. (Sherman (1980))
  • “Between 85% and 90% of respondents claim that their future will be better – more pleasant and less painful – than the future of an average peer” (Armor, 2000, unpublished raw data)
  • Most smokers believe they are less at risk of developing smoking-related diseases than others who smoke. (Weinstein, 1998, unpublished manuscript)
  • “False belief about personal invulnerability to a variety of health threats may lead people to forgo necessary preventative actions.” (See earlier post “Irrational optimism ruins your health, work and life“). However, Armor and Taylor note that it has been difficult to establish that optimistic bias does lead to more risky behaviour.

Armor and Taylor ask, given that such optimistic predictions must come up against unforgiving reality again and again, how are they maintained? They give a variety of possible answers:

  • Perceptual biases affect our experience of the actual outcome, so by an Optimistic Reinterpretation effect, we tell ourselves that our predictions came true (Klaaren, Hodges and Wilson(1994)), or we find an excuse for the worse outcome that preserves our self-esteem (e.g. blaming it on other people). Common sense says that the higher your expectations, the more disappointment you can suffer, but this line of research says that the higher your expectations, the happier you’ll be with the eventual outcome.
  • Memory biases can also affect people’s judgments of whether their predictions were inaccurate.
  • A prediction can be partially self-fulfilling, because having made the optimistic prediction, people work harder to achieve it. Optimistic biases are strongest once a decision on a course of action has been made, rather than while multiple options are open.
  • Optimistic bias thrives on uncertainty: in conditions of near certainty about the future, or readily available evidence, it diminishes.

For full references, see the main Bias and Belief site.

  1. #1 by craigprice on August 23, 2007 - 2:47 pm

    Another great resource is the book “Never Saw it Coming” http://www.press.uchicago.edu/cgi-bin/hfs.cgi/00/190763.ctl by Karen A. Cerulo, show how an epidemic of optimism exists in American culture.

  1. Distorted Reality | 7bloggers

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