George Dvorsky inteviews Keith E. Stanovich in io9:
Cognitive biases are an essential part of the modern definition of rationality in cognitive science.
To think rationally means taking the appropriate action given one’s goals and beliefs — what we call instrumental rationality — and holding beliefs that are in synch with available evidence, or epistemic rationality. Collectively, the many tasks of the heuristics and biases program — and the even wider literature in decision science — comprise the operational definition of rationality in modern cognitive science (see my book Rationality and the Reflective Mind, 2011).
Let me give you some examples of instrumental rationality and irrationality:
- The ability to display disjunctive reasoning in decision making [e.g. Either the Sun orbits the Earth, or the Earth orbits the Sun. The Sun does not orbit the Earth. Therefore, the Earth orbits the Sun.]
- The tendency to show inconsistent preferences because of framing effects [e.g. saying a ‘glass is half empty’ can often be more persuasive than suggesting the inverse; this is somewhat related to the negativity bias]
- The tendency to show a default bias [a.k.a. the status quo bias in which we hold a preference for the way things currently are]
- The tendency to substitute affect for difficult evaluations [sometimes when we have to answer a difficult question we actually answer a related but different question without realizing a substitution has taken place]
- The tendency to over-weight short-term rewards at the expense of long-term well-being [which is also referred to as the current moment bias]
- The tendency to have choices affected by vivid stimuli [e.g. men have been shown to make poor decisions in the presence of an attractive female]
- The tendency for decisions to be affected by irrelevant context