Habits emerge because the brain is constantly looking for ways to save effort. Left to its own devices, the brain will try to make almost any routine into a habit, because habits allow our minds to ramp down more often.
This effort-saving instinct is a huge advantage. An efficient brain requires less room.
An efficient brain also allows us to stop thinking constantly about basic behaviors, such as walking and choosing what to eat, so we can devote mental energy to inventing spears, irrigation systems, and, eventually, airplanes and video games.
When a habit emerges, the brain stops fully participating in decision making. It stops working so hard, or diverts focus to other tasks. So unless you deliberately fight a habit—unless you find new routines—the pattern will unfold automatically.
Problem is that your brain can’t tell the difference between bad and good habits, and so if you have a bad one, it’s always lurking there, waiting for the right cues and rewards.
Without habit loops our habits will be overwhelmed in daily life. We have hundreds of habits we rely on every day.
Habits often occur without our permission but can be reshaped.
In case of delicate habits even small shifts can end the pattern.
Every McDonald’s, for instance, looks the same—the company deliberately tries to standardize stores’ architecture and what employees say to customers, so everything is a consistent cue to trigger eating routines. The foods at some chains are specifically engineered to deliver immediate rewards—the fries, for instance, are designed to begin disintegrating the moment they hit your tongue, in order to deliver a hit of salt and grease as fast as possible, causing your pleasure centers to light up and your brain to lock in the pattern. All the better for tightening the habit loop.
Certain kind of cue and reward that fueled a particular habit is a very powerful alchemy.
Cue — tooth film, reward — beautiful teeth — that had persuaded millions to start a daily ritual.