Habit book notes · Charles Duhigg · 2012

The Power of Habit — the big ideas

A journalist’s popular account of the habit loop — cue, routine, reward — told through stories from people, companies and research.

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A journalist’s bestselling account of habits in individuals, organisations and society, built around the “habit loop” of cue, routine and reward, told through vivid stories.

The big ideas

The habit loop

A cue triggers a routine that delivers a reward; over time the loop becomes automatic.

Keep the cue and reward, change the routine

To change a habit, identify its cue and the reward it delivers, then insert a new routine that delivers a similar reward.

Keystone habits

Some habits seem to spill over and reshape others.

Key concepts

• Habit loop
• Cravings
• Routine substitution
• Keystone habits
• Organisational habits

Limits

• The loop is a helpful simplification; researchers describe habits as broader context–response links, and rewards matter mostly while a habit forms.
• Stories are memorable but are not evidence that a method works in general; “keystone habits” are an appealing idea with limited research.

What the research says

• Wood & Rünger (2016) — Summarised habit research: habits form through repetition in stable contexts, are cued directly by those contexts, and are not easily changed by information or good intentions alone. Limits: A review; the field is still working out how habits and goals interact in everyday life.
• Graybiel (2008) — Reviewed how circuits in the basal ganglia help “chunk” repeated sequences of action into units that can run with little attention. Limits: Largely animal research; brain findings explain mechanisms, not how any one person should build a habit.
• Azrin & Nunn (1973) — Introduced “habit reversal”: becoming aware of the early signs of an unwanted habit and practising a competing response that makes the habit physically hard to do at that moment. Limits: Developed for nervous habits and tics and refined in later clinical research; for compulsive or distressing habits it is used with a professional.

Apply this idea

Map one unwanted habit as cue → routine → reward, then plan a new routine that meets the same reward.

Described in our own words with the source named — not a summary of the whole book.