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Cognitive Biases Yan Bulgak Mar 550 December 04. What Are They A Cognitive Bias is the result of observation by a given person or persons that creates.

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Presentation on theme: "Cognitive Biases Yan Bulgak Mar 550 December 04. What Are They A Cognitive Bias is the result of observation by a given person or persons that creates."— Presentation transcript:

1 Cognitive Biases Yan Bulgak Mar 550 December 04

2 What Are They A Cognitive Bias is the result of observation by a given person or persons that creates a skewed perception of “reality”

3 Confirmation Bias Tendency to accept evidence confirming a held opinion while rejecting contradicting evidence – Underlies the fallacy of seeking scientific proof while not seeking disproval of alternative hypotheses – “You see what you expect to see” The Murano™ Drivers Murano™ is a Registered Trademark of Nissan Corporation. Rules and restrictions apply. No substitutes. Only one per customer. Pre-approved credit available to select customer check store for details.

4 Selection Bias Non-random selection of samples for experiment, thereby biasing the results – Rejection of “bad” data – Early trial termination – Medical trails – excluded data for patients who died or left. See above Murano Drivers example Evans proposed the ``Positivity Bias’’ – people confirm because they can’t think of how to falsify

5 Need For Closure… …and the 2 am drunken phone call to the girl/boy friend you’ve not seen in 3 years. People tend to avoid ambiguity on certain matters

6 Hyperbolic Discounting Tendency to perceive immediate lesser gain as being more attractive than longer-term greater gain (even if greater gain is actually better for them)

7 Outcome Bias …or the “I told you so” effect Judging of past decisions on outcomes, though at decision time outcomes were uncertain – “Good researcher” is one who selected a topic that “worked”

8 Planning Fallacy …or Cheops’s Law “Nothing is ever built on time or within budget” Tendency to underestimate completion times

9 Self-Fulfilling Prophecy Situation which initially false, becomes true through actions on the part of the actor. – Expectations of failure leads to failure

10 Notational Bias A bias toward a particular range of expression that is circumscribed by the notation available – Western music: based on 12 tone equal temperament (TET) – ratio of – Ancient Chinese music used 7 (TET) – Arabic music uses 24 TET

11 Notational Bias (cont) In Computer Science, a language that offers easy access to certain structures can define a pre-disposition toward a particular solution method that will carry over even into other languages – Examples: PERL Lisp and functional languages

12 Causes of Cognitive Bias Attribution Cognitive Dissonance Heuristics (recall Troy’s presentation) – Representativeness – Availability – Anchoring

13 Attribution Relies on Internal/External distinction in attributing blame/responsibility Positivity Effect – Observer will attribute positive actions of a person they dislike to External factors, and negative actions to their internal disposition – Inverse for Negativity Effect In general, people underestimate External effects

14 Attribution (Cont) Other examples: – “Everything is easy to the man who doesn’t have to do it himself” – Backseat drivers – The “I told you so” effect

15 Cognitive Dissonance Simultaneous expression of two contradictory beliefs – E.g. “I believe in the US Constitution” and “I am against free speech” Holding such beliefs creates tension, which is reduced by changing the attitude toward one of the beliefs – the one that is least resistant to change.

16 Examples George Orwell’s 1984 and “Doublethink” – MiniPax, MiniLuv, MiniTruth and MiniPlenty Post-Purchase Rationalization

17 Effort Justification Experimental evidence shows that subjects will rate initially undesirable objects higher if forced to suffer adversity to attain them. – Dissonance between: – Avoiding unpleasant effort – Mediocre outcome – Takes least effort to adjust evaluation of outcome. Job Interviews Military Bootcamp

18 Logical Fallacies Post-hoc ergo propter hoc – Mean global temperatures are higher today than in 1800. The number of pirates today is smaller than in 1800. Therefore pirates and global temperatures are inversely correlated Gambling expectation – Next ball will surely be red… Murphy’s Law

19 The Texas “Sharpshooter” Sharpshooter Story Logical fallacy of adjusting hypothesis to outcome – Disconfirmation as strengthening cultist belief Shakespearean Sonnets and…

20 The Torah/Bible Code Creates a space of letters by choosing every n th letter of the text Look for “patterns” Claim of future prophecies in the Pentateuch of the Torah – Rabin Assassination – 32 Famous Rabbis Experiment

21 The Famous “Prophesy” גיקךןםפףמךםפךי נ ' נבסבהכשגדגגס חצך ' רשאחצזךגעע עהחלוןמנהעראית נקצהממאיטררוןב נךהדמצמדאורןךג נבכעוןםרינקבלע ס ' גיבגשגגגדבהצ ינכמטןךכ 'ר'ר ' עבנמ סבסנולךסרקסרננ Yitzhak RabinAssassin

22 Example LoremipsumdolorsitametconsectetueradipiscingelitPhasellusunelitSedligul alacusportaveldignissimeususcipitsedfelisPhasellusetnibhutaugueconsequ atvehiculaCrasfelissapiensemperafacilisissollicitudincondimentumeuismod orciNamauctorlobortiselitCraseliterosrhoncusacauctorvit N = 5 LoremipsumdolorsitametconsectetueradipiscingelitPhasellusunelitSedligul alacusportaveldig LidsestdclauldlutdsuieissbuouhafsneciluoeeoiultisehsciasaainifietsenauvI minuutn

23 Concerns and Refutations On the non-statistical side: – Clear example of Confirmation and Selection bias Statistical side: – McKay et al showed that Rabbi experiment highly sensitive to minor changes – Liberties and choice of Rabbi names – Other linguistic features, when altered, reduce statistical likelihoods by many orders of magnitude – Replicated experiment with War And Piece can be made to yield significance results of 1 in a million!


25 Bibliography Brock, T. C. and M.C. Green (Eds). Persuasion: Psychological Insights And Perspectives 2 nd Ed. Thousand Oakes, CA: SAGE Publications, 2005 Drosnin, M. The Bible Code. New York, NY: Simon & Shuster, 1997 Evans, Jonathan St. B.T. (Ed). Bias In Human Reasoning: Causes And Consequences. Hove, UK: Lawrence Erlbaum Assoc, 1989 Kahneman, D., Slovic, P. and A. Tversky (Eds). Judgment under Uncertainty: Heuristics and Biases. Cambridge, UK: Cambridge University Press, 1982. McKay B., Bar-Natan D., Bar-Hillel M., and G. Kalai. Solving The Bible Code Puzzle. Statistical Science Vol.14 150-170, 1999 Witztum D, Rips E. and Y. Rosenberg. Equidistant Letter Sequences in the Book of Genesis. Statistical Science Vol.9 429-438, 1994

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