science

Miller's law

Miller's law 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 Miller's law rather than just read about it. In short: Miller's law can refer to four unrelated principles. In communication The Miller's law used in communication was formulated by George Armitage Miller (1920–2012), a professor of psychology at Princeton University, as part of his theory of communication.

Key takeaways

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

Reference excerpt

Miller's law can refer to four unrelated principles.

In communication The Miller's law used in communication was formulated by George Armitage Miller (1920–2012), a professor of psychology at Princeton University, as part of his theory of communication. According to it, one should suspend judgment about what someone else is saying to first understand them without imbuing their message with personal interpretations.

...that in order to understand what someone is telling you, it is necessary for you to assume the person is being truthful, then imagine what could be true about it.

In linguistics

The Miller's law used in linguistics is a sound law of postnasal deaspiration in ancient Greek.

In psychology The Miller's law used in psychology is the observation, also by George Armitage Miller, that the number of objects the average person can hold in working memory is about seven. It was put forward in a 1956 edition of Psychological Review in a paper titled "The Magical Number Seven, Plus or Minus Two".

In software development The Miller's law used in software development was formulated by Mike Beltzner and is named in respect of Dave Miller, long-standing owner of the Bugzilla product:

All discussions of incremental updates to Bugzilla will eventually trend towards proposals for large scale redesigns or feature additions or replacements for Bugzilla.

Worked examples

Example 1 — a first encounter with Miller's law

Start with the simplest possible case. Write down what Miller's law 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 Miller's law 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 Miller's law 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 Miller's law

In research: Miller's law 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 Miller's law 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: Miller's law is common in secondary-school and first-year university syllabi. It links to neighbouring topics Adages, Communication theory, Set index articles, so understanding it makes those chapters shorter.
In everyday life: Look for Miller's law 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 Miller's law in 20 minutes

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

Frequently asked questions

What is Miller's law in simple terms?

Miller's law can refer to four unrelated principles. In communication The Miller's law used in communication was formulated by George Armitage Miller (1920–2012), a professor of psychology at Princeton University, as part of his theory of communication.

Why does Miller's law 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 Miller's law?

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 Miller's law.