Atomic Habits: An Easy and Proven Way to Build Good Habits and Break Bad Ones

by James Clear

By implanting electrodes in the brains of rats, the researchers blocked the release of dopamine. To the surprise of the scientists, the rats lost all will to live.10 They wouldn’t eat. They wouldn’t have sex. They didn’t crave anything. Within a few days, the animals died of thirst. In follow-up studies, other scientists also inhibited the dopamine-releasing parts of the brain, but this time, they squirted little droplets of sugar into the mouths of the dopamine-depleted rats. Their little rat faces lit up with pleasurable grins from the tasty substance. Even though dopamine was blocked, they liked the sugar just as much as before; they just didn’t want it anymore. The ability to experience pleasure remained, but without dopamine, desire died. And without desire, action stopped.11 When other researchers reversed this process and flooded the reward system of the brain with dopamine, animals performed habits at breakneck speed. In one study, mice received a powerful hit of dopamine each time they poked their nose in a box. Within minutes, the mice developed a craving so strong they began poking their nose into the box eight hundred times per hour.