Judgment: Drawing Conclusions from Evidence

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Judgment Drawing Conclusions from Evidence

• Psychology 375
• Brigham Young University
• Craig Rich

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What is Judgement?

• Judgement is the process through which we think a
  bout evidence, draw conclusions, and make
  inferences.
• Deduction rules given, and thus arrive at
  conclusion.
• Induction the end state given/experienced, which
  leads you to find the rules.

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Activity

• Lets Make a Deal
• Suppose you're on a game show, and you're given
  the choice of three doors Behind one door is a
  car behind the others, goats. You pick a door,
  say No. 1, and the host, who knows what's behind
  the doors, opens another door, say No. 3, which
  has a goat. He then says to you, "Do you want to
  pick door No. 2?" Is it to your advantage to
  switch your choice?

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Activity cont.

• Most people believe there is no difference
  between the original choice and changing it after
  a door is removed. This reasoning is called a
  heuristic.
• Heuristic Strategy that risks some error in
  order to gain efficiency.

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Availability

• Judgement based on frequency estimate, which is
  based on how often an event occurs in our life.
• We use what is most available in our memory to
  judge frequency.
• Availability Heuristic estimate of frequency
  based on how easily you think of example of
  relevant category or event.

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Frequency

• Frequency estimate is strongly influenced by
  media exposure
• Which do you fear more
• Mad Cow Disease or heart disease?
• Mad Cow disease has yet to kill one person in the
  US, while heart disease the leading cause of
  death.
• Avian flu or regular flu?
• Avian flu 0 deaths in the US
• Regular flu 36,000 deaths per year

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Anchoring

• Even when you know when the available information
  is wrong, it still affects your answers
• If told 1776 was when George Washington was
  elected President, you will choose an answer
  based on 1776. If told he was elected in 1820,
  the answer changes to be closer to 1820.

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Representativeness

• Representative Heuristic Assumption that the
  category members has all the traits we associate
  with that category.
• Stereotypes
• Gambling fallacy-law of averages fallacy, as if
  the dice were alive. Assumes homogeneity of odds
  despite sample size.

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Illusion of covariation

• Confirmation bias pay attention to evidence that
  supports preexisting beliefs and ignores evidence
  that challenges it.
• To make accurate prediction, you need accurate
  memory, which doesnt always happen. Early
  expectations bias your data gathering, as does
  confirmation bias. Thus scientific method is
  used.

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Data driven covariation

• Algorithms step-by-step problem solving
  procedure
• When people divorce themselves from biases and
  take a scientific approach to judging events,
  they are more likely to come to the correct
  conclusion.