Essentials: The Science of Making & Breaking Habits

The episode frames habits as things the nervous system has learned, often without conscious awareness. Some habits go unnoticed until they become a problem; others serve us well. The host, who introduces himself as Andrew Huberman, a professor of neurobiology and ophthalmology at Stanford School of Medicine, argues that habits make up a large share of daily life.

In fact, it's estimated that up to 70% of our waking behavior is made up of habitual behavior.

If habits are learned, the question becomes what learning is. The answer given is neuroplasticity: the process by which the nervous system changes in response to experience, forming new neural circuits that make some habits more likely to occur and others less likely.

Two ideas from popular books and the psychological literature come first. Immediate goal-based habits produce a specific outcome each time, such as doing zone two cardio four times a week and checking off a box after every session. Identity-based habits attach a larger theme to the same behavior, such as trying to become "a fit person" or an athlete. In that case the immediate goal still exists, but it is linked to a broader picture of oneself.

The episode then tests the common claim that a habit takes a fixed number of days to form. Popular figures range from 18 to 21, 30 or 60 days. Peer-reviewed data tell a different story: a 2010 study with first author Lally found wide variation between individuals forming the same habit.

it can take anywhere from 18 days to as many as 254 days for different individuals to form that habit.

The takeaway drawn from this is that people are highly variable, and difficulty forming one habit does not mean a person cannot easily form others.

To explain why some people form certain habits more easily than others, the host introduces "limbic friction" and suggests the differences probably have something to do with how well people manage it. He is explicit that this is his own shorthand, which pulls together several strands of psychology and neuroscience, and not an established scientific term.

limbic friction is not a term that you're going to find in the formal neurobiological literature or even psychological literature.

Limbic friction describes the strain needed to overcome one of two bodily states. In the first, a person is too anxious to calm down, relax and engage in the activity or thought pattern they want. In the second, they feel too tired, lazy or unmotivated. Both states are tied to the autonomic nervous system, a set of neurons, hormones and chemicals in the brain and body that works like a seesaw between alertness and calm. The episode notes that "wired and tired" is a separate case: it describes what happens after long-term stress has led to exhaustion.

In practice, limbic friction stands for how much effort, or "activation energy," a behavior requires. The episode argues that much of habit formation depends on being in the right state of mind and being able to control one's state of body and mind. It offers the concept as a way to judge whether a given habit will be easy or very challenging to form, and promises a way to measure limbic friction for building new habits and for breaking unwanted ones. That measurement method does not appear in this part of the episode.