Cortisol is the root of anxiety

We prefer to hold on to old experiences. It helps us make sense of the world: It protects us from touching a fire or eating poison berries. But when the expectations cause anxiety, we can adjust them.

If you get what you expect, your brain releases a bit of dopamine and moves on. If it conflicts, cortisol is released, which motivates us to pay more attention, but it also fuels anxiety.