Rational Ignorance

Rational ignorance occurs when the cost of educating oneself on an issue exceeds the potential benefit that the knowledge would provide.

Ignorance about an issue is said to be "rational" when the cost of educating oneself about the issue sufficiently to make an informed decision can outweigh any potential benefit one could reasonably expect to gain from that decision, and so it would be irrational to waste time doing so. This has consequences for the quality of decisions made by large numbers of people, such as general elections, where the probability of any one vote changing the outcome is very small.

The term is most often found in economics, particularly public choice theory, but also used in other disciplines which study rationality and choice, including philosophy (epistemology) and game theory.

The term was coined by Anthony Downs, An Economic Theory of Democracy (New York: Harper & Brothers, 1957)

Bryan Caplan has theorized that voters' anomalous beliefs cannot be attributed solely to rational ignorance; he states that irrational systemic bias is also at work, and he has developed a theory of rational irrationality to explain this. Although some scholars have argued that citizens use "shortcuts" to gain enough knowledge to participate in self-government, the evidence does not support the "shortcut" argument.