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Rational ignorance

Rational ignorance is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Rational ignorance rather than just read about it. In short: Rational ignorance is refraining from acquiring knowledge when the supposed cost of educating oneself on an issue exceeds the expected 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…

Key takeaways

  • Rational ignorance belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Rational ignorance to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Rational ignorance from memory before moving on to harder problems.

Reference excerpt

Rational ignorance is refraining from acquiring knowledge when the supposed cost of educating oneself on an issue exceeds the expected 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 spend time doing so. This has consequences for the quality of decisions made by large numbers of people, such as in 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 in An Economic Theory of Democracy.

Example Consider an employer attempting to choose between two candidates offering to complete a task at the cost of $10/hour. The length of time needed to complete the task may be longer or shorter depending on the skill of the person performing the task, so it is in the employer's best interests to find the fastest worker possible. Assume that the cost of another day of interviewing the candidates is $100. If the employer had deduced from the interviews so far that both candidates would complete the task in somewhere between 195 and 205 hours, it would be in the employer's best interests to choose one or the other by some easily applied metric (for example, flipping a coin) rather than spend the $100 on determining the better candidate, saving at most $100 in labor. In many cases, the decision may be made on the basis of heuristics; a simple decision model which may not be completely accurate. For example, in deciding which brand of prepared food is most nutritious, a shopper might simply choose the one with (for example) the lowest amount of sugar, rather than conducting a research study of all the positive and negative factors in nutrition.

Applications

In marketing Marketers can take advantage of rational ignorance by increasing the complexity of a decision. If the difference in value between a quality product and a poor product is less than the cost to perform the research necessary to differentiate between them, then it is more rational for a consumer to just take his chances on whichever of the two is more convenient and available. Thus, it is in the interest of the producer of a lower value product to proliferate features, options, and package combinations which will tend to increase the number of shoppers who decide it's too much trouble to make an informed decision.

In politics Politics and elections especially display the same dynamic. By increasing the number of issues that a person needs to consider to make a rational decision about candidates or policies, politicians and pundits encourage single-issue voting, party-line voting, jingoism, selling votes, or dart-throwing all of which may tip the playing field in favor of politicians who do not actually represent the electorate. This does not mean that voters make poor and biased decisions: rather that in carrying out their everyday responsibilities (like working and taking care of a family), many people do not have the time to devote to researching every aspect of a candidate's policies. So many people find themselves making rational decisions meaning they let others who are more versed in the subject do the research and they form their opinion based on the evidence provided. They are being rationally ignorant not because they do not care but because they simply do not have the time. Because the cost/benefit ratio increases with increasing costs or decreasing the benefit, the same effect can occur when politicians protect their policy decisions from the preferences of the public. To the degree that the electorate perceives their individual votes to count for less, they will have less incentive to spend any time actually learning any details about the candidate(s). A more nuanced example occurs when a voter identifies with a particular political party, akin to the adoption of a favorite movie critic. Based on prior experience a responsible voter will seek politicians or a political party that draws conclusions about social policy that are similar to what their own conclusions would have been had they done a complete analysis. But when voters find themselves agreeing with the same party or politician across a number of election cycles, many voters simply trust that the same will continue to be true and "vote the ticket", also referred to as straight-ticket voting, instead of wasting time on a complete investigation.

Criticisms Much of the empirical support for the idea of rational ignorance was drawn from studies of voter apathy, which reached particularly strong conclusions in the 1950s. However, apathy appeared to decline sharply in the 1960s as concern about issues such as the Vietnam War mounted, and political polarization increased. This is consistent with expectations from Public Choice Theory; as voters' interest in the results of policy decisions increase, the perceived benefit of the analysis (or the trip to the ballot box) increases, so more people will consider it rational to repair their ignorance. There also may be situations when "the individual may perceive the situation as one that has carry over benefits to other situations, and treat the learning as a capital investment with payoff beyond the specific situation in which it is presented", and not a waste of time even though the time invested in the learning my not have immediate payoff. (Denzou and North, 1994). Additionally, rational ignorance is scrutinized for its broadening effect on the decisions that individuals make in different matters. The investment of time and energy on learning about the specified subject has ramifications on other decision areas. Individuals sometimes ignore this when unconsciously assessing the investment cost versus payout. The external benefits of acquiring knowledge in one area—those benefits occurring in other decision areas—are therefore subject to being overlooked.

See also

Agency (sociology) Argument from authority Bounded rationality Mooers's law Rational irrationality Satisficing Sociology of scientific ignorance

References

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Rational ignorance

Start with the simplest possible case. Write down what Rational ignorance claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Rational ignorance before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Rational ignorance ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Rational ignorance

In research
Rational ignorance appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Rational ignorance in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Rational ignorance is common in secondary-school and first-year university syllabi. It links to neighbouring topics Concepts in epistemology, Game theory, Public choice theory, so understanding it makes those chapters shorter.
In everyday life
Look for Rational ignorance outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Rational ignorance in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Rational ignorance means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Rational ignorance out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Rational ignorance in simple terms?

Rational ignorance is refraining from acquiring knowledge when the supposed cost of educating oneself on an issue exceeds the expected 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 sufficientl…

Why does Rational ignorance matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Rational ignorance?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Rational ignorance.

Tags

  • Concepts in epistemology
  • Game theory
  • Public choice theory

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