Cognitive
Illusions
some errors of reasoning
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
• Cognitive Illusions: ‘Informal Fallacies’ and other
errors of judgment
– Denying the evidence
– Confirmation bias
– The Rule of Typical Things (‘Representativeness Heuristic’)
– Conjunction fallacy
– The Paradox of Choice
– Implicit bias
• How conditionals are falsified
• ‘Strength’ of a proposition: in weakness there is strength
Real Life
Consequences!
Libertarian Paternalism
Denying the Evidence
Angels of Mons
Crop Circles
More crop circles
Availability Error
Anchoring
• In 5 seconds, please estimate the product of
9 x 8 x…x 1
• 9! = 362,880
• Virtually everyone gives an estimate that’s
much too low
• But subjects asked to estimate 1 x 2…x 9 on
the average give even lower answers than
those asked to estimate 9 x 8 x…x 1
Anchoring
Confirmation Bias
We look for evidence that confirms a hypothesis--and
tend to ignore data that would falsify it
A
D
4
7
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
D
4
7
This is the Wason Selection Task: 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
D
2
Good move!
But most
subjects made
the right move
for the wrong
reasons…
4
7
Hypothesis: If a card has a vowel on one side then it has
an even number on the other.
A
2
D
4
E
7
Wasted
move
Hypothesis: If a card has a vowel on one side then it has
an even number on the other.
A
2
D
6
4
7
E
Right. The
hypothesis is
about vowel
cards—says
nothing
other cards.
Hypothesis: If a card has a vowel on one side then it
has an even number on the other.
A
D
4
7
2
6
E
I
Hypothesis: If a card has a vowel on one side then it has
an even number on the other.
A
D
4
7
An odd
number
would
falsify
Turning this
card is
completely
pointless!
A vowel
is consistent
with the
hypothesis
but wasted
move
A vowel
falsifies the
hypothesis
conclusively
Conditionals
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.
Which is more probable?
–Linda is a bank teller
–Linda is a bank teller and is active
in the feminist movement
Where’s Linda?
Bank
tellers
who are
feminist
activists
Bank Tellers
Feminist Activists
A and B can’t be more likely than A!
Things
that are
both A
and B
A’s
B’s
• Predicting A leaves it open whether it is or isn’t a B too.
• Predicting that it’s an A and B is riskier!
The Conjunction Fallacy
• The fallacy of judging a conjunction (‘and statement’ to be more
probable than one of its conjuncts.
• Why is this a fallacy?
– The conjunction is as ‘strong’ as each of its conjuncts i.e. it
conveys at least as much information (and typically more)
than either of its conjuncts.
– The more information we convey the more risk we take!
• Moral: in weakness there is strength
The Paradox of Choice
Maximization Scale
SPRING 2016 STUDENT SCORES
Maximization Scale Student Scores
Possible high/low: 91/13
Schwartz’s results
Fall 2015
Spring 2016
High: 75
High: 86
High: 73
Low: 25
Low: 35
Low: 35
Average: 50
Average: 59
Average: 57
My score: 27
Is maximizing a good strategy?
• Typically (i.e. not always) satisficers maximize while
maximizers fail
• Suppose we want to maximize our utility (happiness, desiresatisfaction)
• + benefit of outcome achieved, e.g. great shoes
• - costs of search and deliberation, e.g. searching Zappos
local malls looking for the perfect pair of shoes.
• Does the difference between satisfactory and great shoes
outweigh the costs of search?
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
résumés to 1,250 employers who had help-wanted
ads…Some applicants were given stereotypically whitesounding names such as Greg; others were given blacksounding names such as Tyrone…Every employer got four
résumés: 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
• Résumés with white-sounding names triggered 50 percent
more callbacks than résumés with black-sounding names.
• High-quality black résumés drew no more calls than the
average black résumés.
• 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.
More results
• The resume sting operation has been repeatedly with similar
results.
• Recently in France employers were sent identical resumes
with applicants identified by either “Franco-French” or
“Arab-sounding” names.
– 30% of the Franco-French applicants got interviews.
– Only 5% of the Arabs got interviews.
• In response, a number of firms are now ‘blind-reviewing’
resume, avoiding names and pictures
• When symphony orchestras began auditioning blind women
instantly went from just the harpist to 1/3 of the orchestra and
has been climbing since
Remedies
• Blind review
– not always possible
– doesn’t eliminate pre-market discrimination
• Equal opportunity regulations
– how can we prove discrimination when the criteria are
soft?
• Affirmative action
– what constitutes a reasonable goal?
• Taking philosophy and learning how to go with your head
instead of your gut!
"Mind bugs operate without us being conscious of them.
They are not special things that happen in our heart because
we are evil."
The Moral
• The following is a false dichotomy:
– Either people (primarily wicked white western males) are
consciously discriminating against women, minorities,
etc.
– Or women, minorities, etc. get more or less equal
treatment.
• We can avoid acting on our implicit biases if we
– recognize that we have them (like recognizing
peculiarities of of minds that produce optical illusions)
and
– Going with our heads rather than our guts!
Philosophy kills mind-bugs!
Don’t go
with your gut!
If we understand the “pecularities of our minds at work” we can
factor them out and make correct judgments.