Habits are simple cue-routine-reward loops that save effort.
In the 1990s, a group of researchers at MIT were studying mice to learn more about how habits are formed in the brain. The mice had to find their way to a piece of chocolate that’d been placed at the end of a T-shaped maze. Using special equipment, the researchers could monitor the brain activity of the mice as they sniffed their way to the chocolate. When the mice were first put in the maze, their brain activity spiked. They could smell the chocolate and they began searching for it. When the researchers repeated the experiment, however, they noticed something interesting. As the mice gradually learned where the chocolate was and memorized how to get there – go straight, then turn left – their brain activity decreased. This process of turning a sequence of actions into an automatic routine is known as “chunking,” and it forms the basis of all habit formation. Its evolutionary role is clear and crucial: it allows the brain to save energy and perform common tasks efficiently....