Science! Basal Ganglia Take the Wheel: The Neuroscience of Habits

Science! Basal Ganglia Take the Wheel: The Neuroscience of Habits

So, we know, intuitively, without a degree in psychology or biology or neuroscience, that something changes when a habit is formed. You know because for whatever reason, one day you just started waking up and DOING THE THING, without needing to plan for it, without needing to reward yourself, even doing it when there is no obvious or immediate reward. One day, you just started doing it. And when that happened, it became easier to do it than to not do it. It just became part of your life.


People who have been going to the gym before or after work for years and years can speak to this. I work out at my home gym now, but when I was using a commercial gym I would sometimes accidentally drive to the gym instead of home on days I was skipping my workout because I was under the weather. It was so built into my life to go to the gym after work, that I started heading there despite knowing I had no plans to go.


Why is this? When I started going to the gym I had to pat myself on the back and give myself a gold star in my habit chart every damn day, set up reminders on my phone and give myself pep talks and sometimes even then wound up on the couch watching Netflix and kicking myself for not going. When did it become easier to go than to not go, and why?


The brain, obviously.


As it turns out, completely different parts of the brain are responsible for “goal-directed behavior” and habits. Goal-directed means that you have to actively and consciously plan to do it. It’s where every intentional habit starts. Habits are automatic and subconscious, meaning you do them without thinking and even in the absence of any goal. When I drove to the gym without my gym bag, there was no goal and no reward – honestly it was a little punishing because it delayed my commute home to make a useless pit stop in the gym parking lot. But I still did this, more than once. That’s because going to the gym was a habit.


In today’s science post I’m going to review the neuroscience behind this in super basic terms. Because this stuff gets extra nerdy. Stay with me though, because understanding this will help you gain so much insight into your behavior and help you kick start your habit growth more efficiently.


Ironically, most of the habits we feel compelled to track are not habits at all.


They are aspiring to become habits, sometimes, but they still require planning and persistence. To understand habit formation, researchers in one study (Packard & McGaugh, 1996) took some mice and taught them to turn right in a maze to get some grub. They turned right many times, getting a yummy reward every time. This is a process called overtraining – when you do something over and over and over until you know the process by heart and exactly what you need to do to get rewarded. Then they put the mice on the other side of the maze.


At first, the mice would use their noggins and figure out that they needed to turn LEFT because they were on the opposite side of the maze. But after overtraining on the first side of the maze, they started automatically turning right even if that was no longer the correct way to turn. Turning right became a habit.


Okay, this is the part where I have to remind you that researchers do weird stuff to mice, like alter their brains. Don’t shoot me, I’m just the messenger.


If the neuroscience researchers made a lesion (a cut) in the hippocampus (which is part of the limbic system in the brain), the mice would always turn right after being trained to do so. If the researchers made a lesion in the dorsal striatum (a part of the basal ganglia), the mice would always think things through and switch course as needed. So, they were incapable of developing a habit of turning right.


Okay, so what have we learned so far?


A part of the brain called the limbic system is responsible for learning and memory. It’s the part of the brain we use to think things through and change course as needed. It’s how we learn new things.


A part of the brain called the basal ganglia is responsible for habitual responses. It’s the part of the brain that allows us to go on auto pilot. When this part of the brain starts to take the wheel, we respond automatically based on environmental cues, rather than having to think through the consequences and plan our actions out in advance.


What does this mean?


Knowing that we have two parts of the brain that hold totally different functions helps us understand a few things. One, it helps us understand how we get stuck in habit ruts we did not want to be in and why it is so hard to override these habits. Those poor rats with their hippocampus lesions just kept turning right. They had no ability to stop and think, “Man, 200 times now no food after turning right, maybe that means I need to change course.” They were quite literally stuck in their ways. Fortunately, no one has gone into your head and lobotomized your limbic system. You can, with effort, stop and think through things, and start intentionally forming a new habit path in your brain by doing something different, again, and again, and again.


It also means that we do need to use our conscious planning mind to develop a habit. We have to over-train our brains before that habit forming part of the brain kicks online. It’s not enough to go to the gym after work a few times on an inconsistent basis and expect it to come easily for us. We have to go again and again and again and again. But when we do, if we really stick with it, we can trust that this other part of our brain WILL turn on the green light and take the wheel.


So if you are working hard right now to develop a new habit, stick with it. It feels like swimming against the current at first, but it is a necessary part of the process.


What areas of your life are you working to over-train right now? How can you apply what you’ve learned today to help you identify ways to improve your habit growth?


As always, primary sources listed below if you want to go nerd out on neuroscience:

Packard, M. G. & McGaugh, J. L. Inactivation of hippocampus or caudate nucleus with lidocaine differentially affects expression of place and response learning. Neurobiological Learning and Memory, 65, 65-72.

Yin, H. H. & Knowlton, B. J. (2006). The role of the basal ganglia in habit formation. Nature, 7, 464-476.

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