LANGUAGE AND THOUGHT

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LANGUAGE AND THOUGHT

• THE PSYCHOLOGY OF PREDICTION 2

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Overview

• Examine research on other biases in
  prediction/hypothesis testing.
• Ask which features of our cognitive apparatus
  give rise to the heuristics used. e.g., memory
  search similarity judgements

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Some Further Heuristics

• Illusory Correlation
• Availability
• Representativeness
• Anchoring and Adjustment

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Links between the heuristics

• Heuristics studied inter-relate.
• E.g. confirmation bias can cause overconfidence
• E.g. availability can cause illusory correlation
• Make sure you look for linkages in the material
  covered

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Illusory Correlation

• First studied by Chapman Chapman (1969)
• Finding subjects who believe that two
  events/properties etc. are correlated will
  bolster this belief when exposed to either
  neutral or mildly disconfirmatory, data

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Experiment on Illusory Correlation

• Clinical psychologists exposed to sets of stimuli
  from Draw a Person Test each labelled with
  diagnosis e.g. depression
• Clinicians asked to evaluate the relationship for
  that data set between features of drawing and
  diagnoses
• Example Is there a correlation between big eyes,
  and a diagnosis of paranoia?
• Results Clincians indicated strong positive
  relationship as present, if they had strong prior
  belief in relationship.
• Replicates even with weak negative correlation in
  data.

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What causes illusory correlation?

• MANY CANDIDATES
• Confirmation bias actively seek only confirming
  instances in retrospect
• Availability confirming instances may be more
  available in memory (either through storage or
  retrieval).
• ?Social factors unwillingness to admit to having
  been wrong.
• Laziness/cognitive miser account, Hypothesis
  error implies hypothesis revision, which is
  effortful,
• Kuhn (Theory of Scientific Revolutions) can only
  replace an existing theory with a new, better
  theory. (Says Popperian falsification is naive).
• How can illusory correlation be cured??

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Availability Heuristic

• One of Three Heuristics Proposed by Kahneman
  Tversky (1973). Others
• Representativeness
• Anchoring and adjustment
• Heuristic for estimating probability
• Relies on
• Structure of memory
• Meta-cognitive ability

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Availability Definition

• A person is said to employ the availability
  heuristic whenever he estimates frequency or
  probability by the ease with which instances or
  associations could be brought to mind

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Availability in Use

• Examples
• Do more English words have R as first or as
  third letter
• Famous name demonstration. Subjects believe that
  gender-balanced lists contain more women (men) if
  the women (men) are more famous.
• Ease of recall is often good clue to probability
  - but not always.

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Causes of death Study Slovic, Fischhoff
Lichtenstein (1976)

• Subjects asked to estimate frequency of various
  causes of death.
• Cause S. estimate Truth
• Tornado 564 90
• Fireworks 160 6
• Asthma 506 1886
• Drowning 1684 7380
• (rates per 200m US residents per year)

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Why do we use the availability heuristic?

• Availability also affects our perception of
  everyday lives Ross Sicoly's study of members
  of couple's perceived responsibility for
  activities
• Availability also related to overconfidence. Hard
  to cure, even if we are aware of it
• based on fundamental aspect of memory search
• generally fail to get necessary feedback.