Text of Conceptual and Perceptual S&V Ch 5: Looking for Truth in Personal Experience Illusions
Conceptual and Perceptual S&V Ch 5: Looking for Truth in Personal Experience Illusions
The Argument Perception, memory and reason are reliable but not infallible. There are errors of reasoning and sensory illusions to which all people are prone. But if we know about them we can avoid being fooled.
Concepts Veridical and non-veridical experience Perception and memory as constructive Judgment: we can avoid being fooled! Conceptual Illusions: Informal Fallacies and other errors of judgment Denying the evidence Confirmation bias Representativeness heuristic (stereotyping) and implicit bias Conjunction fallacy How conditionals are falsified Strength of a proposition
Some Errors of Judgment Denying the evidence Confirmation bias Representativeness heuristic (stereotyping) and implicit bias Conjunction fallacy
Angels of Mons Denying the Evidence
More crop circles
Confirmation Bias AD47 We look for evidence that confirms a hypothesis--and tend to ignore data that would falsify it Hypothesis: If a card has a vowel on one side then it has an even number on the other
How do you determine the most effective means for deciding whether the hypothesis is correct or incorrect? A A D D 4 4 7 7 Most subjects thought that only the A and 4 cards needed to be turned over.
Hypothesis: If a card has a vowel on one side then it has an even number on the other. A A D D 4 4 7 7 2 2
A A D D 4 4 7 7 2 2 E E
A A D D 4 4 7 7 2 2 6 6 E E
A A D D 4 4 7 7 2 2 6 6 E E I I
AD47 An even number supports the hypothesis Turning this card is completely pointless! A vowel is consistent with the hypothesis A vowel falsifies the hypothesis conclusively
For future reference... The hypothesis we were testing was a CONDITIONAL-- an if-then statement. In a conditional the if clause is called the antecedent and the then clause is called the consequent, e.g. If a card has a vowel on one side then it has an even number on the other. A conditional is conclusively shown to be false if its antecedent is true and its consequent is false!
Representativeness Heuristic (stereotyping) The Linda Problem: Linda is 31, single, outspoken and very bright. She majored in philosophy. As a student she was deeply concerned with issues of discrimination and social justice and also participated in antinuclear demonstrations. Rank the following in order of likelihood: Linda is an insurance salesperson Linda is a bank teller Linda is a bank teller and is active in the feminist movement
Bank TellersFeminist Activists Bank tellers who are feminist activists Wheres Linda?
A and B cant be more likely Predicting A leaves it open whether it is or isnt a B too. Predicting that its an A and B is riskier! AsBs Things that are both A and B
The Conjunction Fallacy 1.Linda is a bank teller and Linda is active in the feminist movement. 2.Linda is a bank teller (1) cant be more probable than (2) because it is stronger, i.e. conveys more information, than (2) A conjunction (and statement) can never be more probable than one of its conjuncts! Moral: In weakness there is strength!
Implicit Bias Many cognitive processes that affect behavior are unconscious in nature and are inaccessible to observation by the actor. These implicit processes affect perception, influence behavior, and color interpretation of past events.
The Implicit Association Test The IAT requires the rapid categorization of various stimulus objects, such that easier pairings (and faster responses) are interpreted as being more strongly associated in memory than more difficult pairings (slower responses).
The Implicit Association Test The IAT measures the thumbprint of culture on our minds. 88 percent of white people had a pro-white or anti-black implicit bias Nearly 83 percent of heterosexuals showed implicit biases for straight people over gays and lesbians More than two-thirds of non-Arab, non-Muslim volunteers displayed implicit biases against Arab Muslims.
The Implicit Association Test We all have the thumbprint of culture on our minds 48 percent of blacks showed a pro-white or anti- black bias 36 percent of Arab Muslims showed an anti- Muslim bias. 38 percent of gays and lesbians showed a bias for straight people over homosexuals.
Real World Consequences The results of the IAT are confirmed by real world tests of biased behavior Economists at the Massachusetts Institute of Technology and the University of Chicago recently sent out 5,000 rsums to 1,250 employers who had help-wanted adsSome applicants were given stereotypically white-sounding names such as Greg; others were given black-sounding names such as TyroneEvery employer got four rsums: an average white applicant, an average black applicant, a highly skilled white applicant and a highly skilled black applicant.
Employers wanted minorities! Interviews beforehand with human resources managers at many companies in Boston and Chicago had led the economists to believe that black applicants would be more likely to get interview calls. Employers said they were hungry for qualified minorities and were aggressively seeking diversity.
Results of the Experiment Rsums with white-sounding names triggered 50 percent more callbacks than rsums with black- sounding names. High-quality black rsums drew no more calls than the average black rsums. Highly skilled candidates with white names got more calls than average white candidates, but lower-skilled candidates with white names got many more callbacks than even highly skilled black applicants.
"Mind bugs operate without us being conscious of them. They are not special things that happen in our heart because we are evil."
Philosophy kills mind-bugs! If we understand the pecularities of our minds at work we can factor them out and make correct judgments. Dont go with your gut!
Perceptual Illusions Should we trust the evidence of the senses? Things are not always as they seem Trust me--Im a politician.
The morals to be drawn from the discussion that follows: Perception (and memory) are reliable but not infallible. Knowledge doesnt require certainty--but we should know when to be careful. If we know whats going on we can avoid being fooled.
Perception is constructive What we perceive is determined not only by the senses but by What we know What we expect What we believe What our psychological state is
When we should be careful Our conclusions are at odds with all known past experience Our experience is uncorroborated Peculiarities of our minds could be at work I never saw a purple cow
Theres is a first time for everything
Checks and more scintillating gridsscintillating grids
Parallel lines? The Caf Wall Illusion in motion
Poggendorff Interactive The Poggendorff Illusion
Whats the illusion here?
Heres some more of the same Maybe you dont believe me so
Munker-White Illusion Another color illusion
We see what we expect to see
We expect to see faces Face on Mars, Face in beans,...and more faces
How old is she?
Young Woman/Old Woman
Another young/old woman
So big size and size constancy
Look familiar? Mller-Lyer Illusion (interactive)
Im not paranoid Someone really is out to get me
Autokinetic effect: illusions of motion UFOs The Rotating Snake (nausea warning)The Rotating Snake (nausea warning) Stepping Feet