7 Deadly Sins – Overconfidence

Massimo Piatelli-Palmarini writes in his deliciously written book “Inevitable Illusions” about the 7 deadly sins of our cognitive illusions.

His first sin is overconfidence. This is where we feel certain about our knowledge of something, but our knowledge does not really warrant such confidence.

He describes experiments where subjects are asked to answer questions and then rate how confident they are about each answer.  Experiments show that our confidence leads our knowledge.

We think we know something more than we really know.

The results of the experiments also bring about something sobering: we are most overconfident in areas we are more knowledgeable about.  That is, the difference between the level of our overconfidence and knowledge in these areas is bigger than the difference between our level of overconfidence and knowledge in other areas - hence we tend to make mistakes of overconfidence in our areas of expertise.