The Science of Making & Breaking Habits

KEYPOINTS

• 01

  There is no fixed number of days to form a habit

  Huberman cites a 2010 study (first author Lally) on the habit of walking after dinner. People took anywhere from 18 to 254 days to form it, judged by doing it about 85% of the time with little mental effort. Being slow to form one habit does not mean you will be slow with others.

• 02

  'Limbic friction' is the activation energy a habit requires

  Huberman coined the term for the conscious, top-down effort needed to override an autonomic state that blocks a behavior. That state can be too tired or unmotivated for an energetic habit like cardio, or too anxious and wired for a calming one like meditation. It is more concrete than 'motivation' because it points to specific circuits and a state you can assess.

• 03

  Habit strength depends on context-independence and low limbic friction

  Drawing on Wendy Wood and Dennis Rünger's review 'Psychology of Habit' (Annual Review of Psychology), a strong habit happens the same way whether you are at home or traveling, and takes little activation energy. The goal is automaticity. Brushing your teeth is the model: most people do it even after a terrible night.

• 04

  Linchpin habits are enjoyable ones that make other habits easier

  For Huberman, cardio and resistance training three to four times a week each, typically early in the day, make sleep, alertness, hydration and better food choices easier. Linchpin habits are always ones you enjoy.

• 05

  Walking through a habit's steps once makes it markedly more likely

  Procedural memory holds the sequence of steps needed for an outcome, like a recipe. Mentally rehearsing every step of a new habit (walk into the kitchen, turn on the espresso machine, pull the shot) even once shifts the likelihood of doing it from unlikely to very likely over time, according to the psychology literature. Mechanistically this is Hebbian learning: NMDA receptors respond to strong input by recruiting more receptors, lowering the firing threshold of the neurons the habit will use.

• 06

  Task bracketing in the dorsolateral striatum anchors habits

  The basal ganglia contain go and no-go circuits for doing and not doing things. Recordings in animals and humans show that the dorsolateral striatum is active at the start and end of a habitual behavior rather than during it, bracketing the task. Strong bracketing is what makes a habit happen even when you are tired, distracted or overwhelmed.

• 07

  Anchor habits to brain-body states, not clock times

  Huberman says a fixed time helps in the short term, but over the long term the nervous system generates behavior based on state: activation, focus and fatigue. So he divides the day into phases tied to their neurochemistry, rather than rigid times.

• 08

  Reward prediction error can be extended around a habit

  Dopamine rises in anticipation, rises most for unexpected rewards, and falls below baseline when an expected reward is withdrawn, for example checking your phone at minute 50 of a 60-minute writing block. Huberman's 'dopamine spotlighting' means honestly anticipating the hard start and the good feeling afterward, so the whole time window, including the brackets, gets associated with reward. He stresses that you cannot lie to yourself about enjoying the hard parts.

• 09

  Breaking a habit requires weakening its circuits (long-term depression)

  Huberman says reminders and sticky notes work only in the short term. Shocks and monetary penalties work when people are monitored but fail when people police themselves. Because the neurons for a bad habit fire together reflexively, the practical lever is the moment right after you catch yourself doing it.