Are We Prisoners of Habit or Are We Fundamentally Flexible?
The brain’s greatest trick is that it runs set programs and is also malleable.
Posted May 4, 2021 | Reviewed by Jessica Schrader
- The brain has powerful systems for generating habitual behavior.
- The pandemic has taught many people how to be more flexible.
- As powerful as habits are, we are also profoundly flexible beings.
Today is a big day for neuroscience in the publishing world with the release of three exciting new books about the brain.
One is Models of the Mind by Grace Lindsay of University College London, a book that takes a deep dive into the history of computational neuroscience and comes to innovative conclusions about where the study of the brain is headed. I will discuss this book in a future post.
The second book released today, and the one I want to discuss here, is Hard to Break by Russell Poldrack of Stanford University, which gives an up-to-the-minute tour of the neuroscience of habit-forming, and particularly how we acquire and keep bad habits. It’s a great counterpoint to the third neuroscience book released today, by me, An Internet in Your Head.
What strikes me most about this book is how different its vision of brain function is compared to the picture I present in An Internet in Your Head. Poldrack, an accomplished author, vividly demonstrates how much our lives are dominated by habit, starting with our morning routines. Habits are essential in our individual lives, and indeed for society: modern civilization would be unthinkable if we couldn't rely on other people sticking to basic habits. It’s not just assuming trains are running on time that links our habits and those of others around us: it’s almost all of our plans for the day, and even our own sense of self that rely on the predictable habits of others.
As Poldrack shows, the brain’s systems for generating habitual behavior are powerful and, to a degree, all-consuming. When we are engaged in a habitual behavior, it is because certain parts of the brain have commandeered many of the available neural resources and are running a set program that causes us to do the same thing we have done before. We are almost powerless to do anything other than carry out habitual behavior once it has been initiated. This is what makes habits so hard to break.
Yet if there is one thing that we have all learned from the pandemic, it is how to be flexible. For many, the changes wrought by the pandemic have been unwelcome and difficult. But aside from those tragically lost to the virus, most people will find a way to adapt to our new reality.
This is by no means to suggest that all is for the best in the best of all possible worlds. The point is that humans, by dint of inhabiting almost all terrestrial ecologies, have faced an incredible diversity of challenges in our past, and have withstood.
Our social skills are most responsible for this: we depend on each other to do the hardest and most essential work of life: food gathering and childcare. The ability to work together requires a wide array of flexible subskills including remembering past interactions with others and with the environment, empathizing, maintaining polite fictions when necessary, and imagining the future.
There are also the moment-to-moment adjustments we make during social interactions, which require yet more flexibility. For example, we blink our eyes more than twice as often during a conversation than we do when we are doing other cognitively-demanding activities like reading. The blinks seem to enhance our ability to extract visual information from the environment. And there is a lot to extract, much of which is unpredictable—a slightly upturned corner of the mouth, a tiny wrinkle of the nose, a wink. It is these small, unpredictable interactions that allow us to band together to accomplish demanding but essential tasks like finding food and taking care of kids. Habits can make these jobs easier to some extent but, as any parent can attest, raising kids requires almost heroic flexibility (especially when they and you are hungry).
As I argue in An Internet in Your Head, the brain has a flexible system for organizing neural activity. Flexibility is crucial for exchanging information among different parts of the brain that perform different tasks. This "routing system" supports the goal of dealing with an ever-changing world. The main proposal in the book is that the brain's routing system resembles that of the internet, since both must solve similar kinds of problems. The internet is replete with strategies and mechanisms that super-charge flexibility on vast networks, and that perform flexible functions. The internet metaphor for the brain highlights these solutions and the book draws linkages between engineered strategies and candidate neural mechanisms.
Flexibility is the brain's natural state. Brains arrive from the factory in a highly malleable state: if one could magically rewire a brain in utero such that the eyes fed the auditory regions of the brain, the creature could yet see, albeit imperfectly. This is in fact what MIT researcher Mriganka Sur has demonstrated in newborn ferrets—without magic. Flexibility is reduced once the brain has substantial contact with the outside world, and throughout childhood and adolescence. But flexibility persists well into old age. It is normal to change our behaviors, thoughts, actions, and even our habits at almost any stage of life. The outside world demands this: it too is always changing, but not necessarily in predictable or rationally comprehensible ways.
Even our taste in art changes from week to week. And contrary to popular belief, these tastes are less, not more, stable as we get older.
The main way flexibility in brains is reduced is when we learn a task. Out of the many patterns of behavior achievable with our limbs or vocal apparatus, and across the range of experiences we can derive from our senses, learning involves fixing in place a small subset of actions, experiences, and knowledge for recurring use. A habit is simply the linking of several learned tasks.
How do we reconcile the brain's flexibility and its fixity?
As powerful as habits are—and Poldrack’s book makes a compelling and enjoyable case for this—we are also profoundly flexible beings. I think this ultimately reflects the deepest laws in our biology, which have to do with genetics. Our genes fix certain traits in families, across species, and in related groups of species. But there is always the possibility for change through mutation, which, over longer time periods, allows living beings to adapt to a changing world. The forces of fixity and change are in dynamic balance. Brains perform a similar balancing act in real time.
Though other species employ habit and flexibility, there is for us a heightened interplay between the two. Perhaps the way we balance habit and flexibility is what makes us human.
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