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:
What Are They A Cognitive Bias is the result of observation by a given person or persons that creates a skewed perception of “reality”
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.
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
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
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)
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”
Planning Fallacy …or Cheops’s Law “Nothing is ever built on time or within budget” Tendency to underestimate completion times
Self-Fulfilling Prophecy Situation which initially false, becomes true through actions on the part of the actor. – Expectations of failure leads to failure
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
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
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
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
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.
Examples George Orwell’s 1984 and “Doublethink” – MiniPax, MiniLuv, MiniTruth and MiniPlenty Post-Purchase Rationalization
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
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
The Texas “Sharpshooter” Sharpshooter Story Logical fallacy of adjusting hypothesis to outcome – Disconfirmation as strengthening cultist belief Shakespearean Sonnets and…
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
Example LoremipsumdolorsitametconsectetueradipiscingelitPhasellusunelitSedligul alacusportaveldignissimeususcipitsedfelisPhasellusetnibhutaugueconsequ atvehiculaCrasfelissapiensemperafacilisissollicitudincondimentumeuismod orciNamauctorlobortiselitCraseliterosrhoncusacauctorvit N = 5 LoremipsumdolorsitametconsectetueradipiscingelitPhasellusunelitSedligul alacusportaveldig LidsestdclauldlutdsuieissbuouhafsneciluoeeoiultisehsciasaainifietsenauvI minuutn
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!
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 http://en.wikipedia.org/wiki/List_of_cognitive_biases Witztum D, Rips E. and Y. Rosenberg. Equidistant Letter Sequences in the Book of Genesis. Statistical Science Vol.9 429-438, 1994