Limbic friction quantifies the activation energy needed to engage in a particular behavior, and managing one's state of body and mind is crucial for habit formation.

“So, as we march forward, what you're going to find is that this phrase or this term limbic friction is going to be a useful metric or way for you to touch in with yourself and address whether or not you are likely to be able to form a certain habit easily or whether or not it's going to be very challenging. And I'm going to teach you a way to measure your degree of limbic friction. That is, how much activation energy it will take in order for you to execute a new habit. And I'm going to teach you how to measure your limbic friction and activation energy for how likely it is that you're going to be able to break a habit that you don't want to have.”

“Now limbic friction is not a term that you're going to find in the formal neurobiological literature or even psychological literature. It's frankly a term that I coined to encompass a number of different pieces of the psychology and neuroscience literature. Limbic friction is a shorthand way that I use to describe the strain that's required in order to overcome one of two states within your body. One state is one of anxiousness where you're really anxious and therefore you can't calm down. You can't relax and therefore you can't engage in some particular activity or thought pattern that you would like. The other state is one in which you're feeling too tired or lazy or not motivated. Both of those states, feeling too alert and too calm, if you will, relate to the function of the so-called autonomic nervous system, a set of neurons and hormones and chemicals in your brain and body that act as sort of a seessaw. You're either alert or calm. You're either asleep or stressed. Those two states are not compatible with one another.”