Are the general public accurate at predicting probability?
- No- Russo & Shoemaker (1989)
- P's given 10 items of questions they were very unlikely to possess accurate knowledge of, and asked to make a high and low estimate about their values in which they are 90% sure the answer falls in
- E.g. number of books in the old testament or MLK's age at death
- Found that p's usually showed overconfidence despite inaccurate predictions, regardless of training, intelligence or the way confidence is elicited (Lichtenstein, Fischhoff & Phillips, 1982)
- This has been interpreted as a tendency to be overoptimistic (optimism bias- Weinstein, 1980)
- Argued by some psychologists such as Juslin that this is an artefact and there were too many questions with which common sensical answers were garnered, leading to a high optimism as this overconfidence is not present when people make perceptual judgments