Habit book notes · Katy Milkman · 2021

How to Change — the big ideas

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A behavioural scientist’s guide that matches strategies to the obstacle in the way — starting, impulsivity, procrastination, forgetfulness, the pull of the easy option, confidence and conformity.

The big ideas

Diagnose the obstacle first

Different barriers need different tools; a one-size strategy fails because the obstacle differs.

Fresh starts and temptation bundling

Use meaningful new beginnings to start, and pair a hard habit with a treat you allow only during it.

Build in flexibility

Allowing a few emergency skips can help people stick with a plan rather than abandoning it.

Key concepts

• Fresh start effect
• Temptation bundling
• Commitment devices
• Flexibility
• Social influence

Limits

• Many studies are short-term field experiments; effects often fade when a programme ends.
• Megastudy results show experts struggle to predict what works — a reason to test ideas on yourself.

What the research says

• Dai, Milkman & Riis (2014) — Gym visits, goal-related searches and commitments rose after temporal landmarks — a new week, month or year, a birthday, a holiday — which the authors called the “fresh start effect”. Limits: Mostly observational data; a fresh start helps people begin, not necessarily continue.
• Milkman, Minson & Volpp (2014) — People who could listen to gripping audiobooks only while at the gym went more often at first than a comparison group — the “temptation bundling” effect — though the boost faded after a holiday break. Limits: One field experiment, and the effect decayed over time.
• Milkman, Gromet, Ho, Kay, Lee, Pandiloski and colleagues (2021) — Tested 54 different four-week programmes on more than 61,000 gym members at once. Many raised gym visits during the programme; among the strongest were small rewards for returning after a missed workout. Neither experts nor the public predicted well which would work. Limits: Most effects faded after the programme ended, and the incentives were small.

Apply this idea

Name the main obstacle to one habit, then pick one strategy that targets that obstacle specifically.

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