Many people make plans to change their behavior, but plans often . The psychologist Peter Gollwitzer studied a simple called an implementation intention. Instead of ‘I will exercise more’, a person decides when and where: ‘When I lunch on Monday, I will walk for twenty .’ A large review of found that such if-then plans people much more to reach their .

People often admire those who seem to have great self-control, assuming that they constantly resist temptation through willpower. Research by the psychologist Wendy Wood and her colleagues suggests a different picture.

In studies that asked people to report their thoughts and actions throughout the day, Wood found that about 43 percent of daily behavior was performed almost automatically, usually in the same setting each day. Other research has found that people who score high on self-control do not spend more time resisting temptations. Instead, they tend to have routines that make good behavior automatic, so they face fewer temptations in the first place.

These findings shift the focus from willpower to environment. Someone who wants to study more might keep the phone in another room, leave the textbook open on the desk, and study at the same time each day. Someone who wants to eat more healthily might avoid keeping snacks at home.

Willpower still matters, especially at the beginning. But once a habit forms, the behavior requires much less effort, and it can continue even on days when motivation is low.