According to researcher Gregory Berns, the meaning of life is found in the design of the brain. Behavior is controlled by the brain's pleasure system and reward system.

Happiness = pleasure + reward

Most people seek pleasure, but this is hard to find: it comes mostly from genes and luck. It's easier to find reward.

Reward = new + challenge

Reward comes from mastering something new. When working with something unexpected, the brain releases the chemical dopamine, which gives us motivation and purpose. Challenge or good stress releases the chemical cortisol, which excites us. It's easy to find reward:

• Try different kinds of exercise and food.
• Work puzzles.
• Try, learn, and do new things.