Thinking Critically About Psychological Science

A Questionnaire

• Instructions: Below are a number of factual questions, each of which has two possible answers. We are interested in studying the perceived difficulty of these items.

• In each case, one answer has a blank beside it which may or may not be the correct answer.

• In the blank, assign a probability that it is in fact the right answer.

A Questionnaire• Here is a sample question:

Absinthe is a. a precious stone____% b. a liqueur

• Your task on this would be to indicate what probability (from 1 to 100%) you believe that absinthe is indeed a liqueur. For example, if you are pretty sure that absinthe is a liqueur, you might mark, say, 85%. If you felt equally sure that absinthe is not a liqueur, you might put 15%. If you felt it 50--50 (you have no idea), you might put 50%. In summary, your task is simply to estimate what odds you would give that the answer next to the blank is the correct answer.

Let’s Make a Deal!

Let’s Make a Deal (Old Days!)

Monty Hall

Monty Hall Problem

• Example of OVERCONFIDENCE

• Truth of the matter is… We tend to be more confident than correct!

• Another example:– WREAT WATER– ETRYN ENTRY RESAI– GRABE BARGE

Remember That Questionnaire?

• Now respond to these questions.• Instructions:• Below are a number of factual questions, each of

which has two possible answers. We are interested in studying the perceived difficulty of these items. The correct answer has a blank beside it.

• Pretend you hadn't been told the right answer. What probability would you have assigned to the answer with the blank beside it?

Remember That Questionnaire?

Absinthe is

a. a precious stone____% b. a liqueur

Remember That Questionnaire?

Hindsight Bias

• “I-knew-it-all-along” phenomenon• The tendency to believe, after learning an

outcome, that one would have foreseen it.

• Other examples:– 9/11– Virginia Tech Massacre

Bottom Line

• Hindsight bias and overconfidence often lead us to overestimate our intuition.

• These errors show why we need rigorous psychological research.