8/30/2019
Critical Thinking
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What About
Intuition &
Common Sense?
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The Monty Hall
Problem
Counterintuitive
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Limits of
Intuition and
Common
Sense
• Research shows that thinking, memory,
and attitudes operate on conscious and
unconscious levels.
• Most of an individual’s mental life
happens automatically, but
intuition can lead him/her astray.
• Flaws in intuitive thinking:
• Hindsight bias
• Overconfidence
• Perceiving patterns in random
events
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Hindsight Bias is the “I-knew-itall-along” phenomenon.
Hindsight Bias
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Hindsight bias
• I knew that was going to
happen!
• If you knew your marriage
would end in divorce, why
did you get married?
Hindsight is 20/20
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Overconfidence
• Sometimes we think we know more than we
actually know.
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People perceive patterns to make sense of their
world.
Perceiving
Order in
Random
Events
Even in random, unrelated data people find order.
Random sequences often do not look random.
People trust their intuition more than they should.
Intuitive thinking is flawed.
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Law of large numbers
Given large numbers of
random outcomes, a few are
likely to express order.
• Angelo and Maria Gallina
won two California lottery
games on the same day.
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Crowd wisdom
• Applying the law of large numbers to realworld problems
• The larger the number of guesses, the closer
to the correct solution
• This is why research that is conducted on
only a few people is practically worthless,
research conducted on a few thousand is
surprisingly accurate.
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Critical Thinking
• Critical thinking does not accept arguments and
conclusions blindly.
• It examines assumptions, discerns hidden values, evaluates
evidence and assesses conclusions.
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Conspiracy Theories
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More Conspiracy
Theories
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It is raining and I see a bright flash of
light through my curtains
a) A UFO is flying by my house
Parsimony
(Occam’s
Razor)
b) It was lightning
I put a roast in the oven, and only an
hour later it was burnt
a) Someone broke into my house
unnoticed and turned up the
temperature on the stove, then
broke in an hour later and put it back
to normal
b) My stove isn’t working right – needs
a new temperature gauge
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Examine Assumptions
• Look for hidden agenda – what’s in it for
them?
• Evaluate evidence and assess
conclusions
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Q-Ray makers ordered to pay $16M in refunds to
consumers – CBC news Jan 07, 2008
The court said Q-Ray's claims about how the bracelets
worked through "enhancing the flow of bio-energy" were
nonsense.
"Defendants might as well have said: Beneficent creatures
from the 17th dimension use this bracelet as a beacon to
locate people who need pain relief and whisk them off to
their home world every night to provide help in ways
unknown to our science," he wrote in his decision.
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Read the Fine Print
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Vaccination scare
• Andrew Wakefield started it
• Small study – only 12 people
– case reports
• Later discovered he had
altered his data
• Lost his medical license
• Motive? $$$$
• Example of illusory
correlation
A porn star?
Really?
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The Scientific Attitude
• The scientific attitude is
composed of curiosity (passion
for exploration), skepticism
(doubting and questioning) and
humility (ability to accept
responsibility when wrong).
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Facts, opinions
and truth
• Facts – provable, observable,
measurable – true or false
• Opinions –based on emotion,
attitude or personal belief. Cannot
be proven or disproven
• Truth – being in accord with fact or
reality
• Everyone is entitled to their own
opinion not their own facts.
• Opinions are not inherently equal.
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• “People say that…” (Which
people? Who specifically?)
• “Everybody knows …” (Again,
can you be more specific?)
• “I’ve heard that…” (Where
did you hear it?)
• Do some research
• Check multiple sources
• Look for the facts
Critical thinking in the 21st
Century
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But remember to keep an
open mind!
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