Chapter 4: Testimonials

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Chapter 4 Testimonials Case StudyEvidence

• Keith E. Stanovich

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Placebo Effects and the Amazing Randi

• Nature of the evidence cant be subjective
• Case studies and testimonials are worthless as
  evidence.

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The Place of the Case Study

• Case studies do not prove anything, rather they
  provide a topic of further investigation
• Case studies and testimonials stand as isolated
  phenomena. They lack the comparative information
  necessary to prove that a particular theory or
  therapy is superior.
• (Stanovich, p. 56)

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Why Testimonials are WorthlessPlacebo Effects

• Placebo Effect tendency for people to report the
  treatment helped them regardless if it was a real
  therapeutic element. (Example Wizard of Oz)
• The placebo is controlled
• Why are testimonials worthless?
• Testimonials are too easy to generate
• Thomas Gilvovich (1991) states, "with the body so
  effective in healing itself, many who seek
  medical assistance will experience a positive
  outcome even if the doctor does nothing
  special."
• What works for one person, might not work for
  someone else (infomercials, diet pills, etc.)

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The Vividness Problem

• Vividness Effect When faced with a problem,
  people retrieve from memory the information that
  seems relevant to the situation at hand.
• Example Purchasing a car we buy items based on
  recommendations
• Example Car crashes vs. jumbo jet crash- we
  remember the larger injured and we take more
  action
• The vividness effect merely misleads our own
  personal judgment, largely due to media.

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The Overwhelming Impact of the Single Case

• Picture vs. Numbers
• Case Studies
• Rhea Sullins
• Vividness

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The Amazing Randi

• Fighting Fire with Fire!
• Sighting Evidence
• Exposing Falsehoods

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Testimonials Open the Door to Pseudoscience

• Oprah showing a surgical procedure in 1995
• Choosing a vehicle to purchase

Scientific or Friendly Advice?
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Take Home Point

• Case studies and testimonials should not be used
  for evidence, but as a stepping stone into
  further investigation in a particular topic.
• People overweight evidence that is more vivid
  and, hence, more retrievable from memory.
  vividness effect
• (Stanovich, p. 71)