How Meditation Changes the Brain

Yes, and Davidson does not hedge on it. There is no question that meditation changes the brain, covering both the function of the brain and its structure, and the evidence for that is overwhelming.

The debate has never been whether. It is which part, by how much, and on what timescale.

The specific claim that short amounts of meditation increase gray matter in particular brain regions. Davidson says plainly that this evidence has really not held up.

He also flags a finding that runs opposite to intuition: some reported effects go the wrong way, with more practice associated with less structural change.

When he started meditating more than thirty years ago he had a genuine and severe phobia of public speaking. Now he not only lacks the anxiety, he enjoys it.

The part that makes it more than a self-report: his biometrics agree. Wearing a ring that tracks heart rate and heart rate variability, his physiology drops into a deeply relaxed state when he is in front of a crowd. That would have been unthinkable twenty or thirty years earlier.

It sets up the question the episode is really about. A change that deep is hard to imagine happening with no change in the brain at all. But wanting that to be true is exactly the pressure that produces overstated science.

Cort names the pattern directly. A study says mindfulness changes your brain, then a new study says it does not, and the headlines rarely explain what is even meant by change.

Functional change is a difference in how the brain is working, expressed as differences in activation patterns across regions. Structural change is a difference in the physical brain itself.

The relationship runs one way. You can change function without any change in structure. But if structure changes, it almost always implies a change in function too.

Gray matter is the cell bodies of neurons, which show up as gray on an MRI scan. White matter is the axons, the fibers that connect one region of the brain to another.

Both count as structural measures. But as the episode goes on, this distinction turns out to carry almost the entire argument.

From reports in the early 2000s. Beginners took a two month course in mindfulness based stress reduction, the program Jon Kabat-Zinn founded in the late 1970s. It runs once a week for two months, mostly awareness practices with some light yoga and prescribed home practice, totaling somewhere between twenty-four and thirty hours.

Those reports described increases in gray matter in places like the prefrontal cortex. The press wrote itself: grow your prefrontal cortex with meditation.

Because it is the primary site of the central executive network, the system responsible for goal-directed behavior. Davidson uses an ordinary example. You realize you need groceries, you plan to get in the car, you make a list, you drive there, you buy the things. All of that is navigated by the prefrontal cortex.

It also handles voluntary regulation of attention, deciding to attend to this and not that. Cort adds the piece most people care about: forming a good habit or dropping a bad one depends on the same network.

The same machinery that confers those capacities also causes an enormous amount of suffering. It is what allows you to be engaged in an activity while simultaneously worrying about the future or ruminating about the past.

Davidson borrows the answer from Robert Sapolsky, the Stanford neurobiologist whose book carries that title. Zebras have a very puny prefrontal cortex. They do not worry about the future or ruminate about the past because they lack the biological machinery to do it.

In some sense they live much more in the present moment, and they do not get ulcers because of it. Humans do.

Published in Scientific Reports, it summarized the evidence on mindfulness based stress reduction and concluded there were structural changes in the brain, largely in areas of the central executive network. It looked like the case was closed.

The editors of the journal retracted it in 2025, against the advice of the authors. Davidson calls this kind of extraordinary, and it is. Papers are usually retracted by their own authors in light of new evidence. Having the editors override the authors is rare.

The reason: the authors had omitted important data. Include that data in the meta-analysis and the effects disappear.

In 2022 his group published in Science Advances and reported no structural differences between mindfulness based stress reduction, an active control, and a waitlist control in a three arm randomized controlled trial. For gray matter growth from short amounts of meditation, the evidence has really not held up.

But read that carefully, because the same dataset is where they found white matter changes, in pathways important for self-regulation, after roughly twenty to thirty hours of practice. The volume did not move. The wiring did.

That distinction is the whole argument of the episode. A null result on gray matter is not a null result on meditation.

Some reports looked at the relationship between length of practice and the size of structural change, and found the opposite of what you would expect. The more meditation people did, the less the structural change.

Davidson's answer is blunt. If more practice always meant more gray matter in a region, it strains credulity, because that would be like phrenology. There would eventually be a bump protruding from your head.

Phrenology was the discredited nineteenth century idea that character could be read from the shape of the skull. Invoking it is not a compliment.

One comes from the study of expertise. Davidson and Dahl are co-authoring a paper with Leandro Chernikov, a founder of Atentamente in Mexico, on a skill based model of contemplative practice.

The argument is that expertise brings increased effortlessness. There may be a transient increase in certain brain areas early on, which then recedes as expertise develops. Early in practice more may help. With mastery it begins to fall away.

Because across the evidence, not just in meditation but in skill acquisition generally, white matter changes appear much more sensitive to environmental and behavioral factors than gray matter changes are.

The headlines measured the size of the parts. The thing that actually responds is the connection between them.

Faster than most people would guess. The example Davidson gives is juggling, a complex visual motor skill. There are data showing that one and a half hours of juggling lessons in beginning jugglers is associated with white matter changes in the brain.

The catch matters as much as the finding. It is very dynamic. If you stop juggling, those changes would likely recede.

White matter changes in pathways that are really important for self-regulation, after roughly twenty to thirty hours of practice. Crucially, this was in the same dataset that showed no gray matter change.

Same people, same scans. The volume did not move. The wiring did.

Davidson describes very new and not yet published data from the Healthy Minds program: approximately five minutes a day for thirty days is also associated with white matter changes in the brain.

He is careful to flag that it is unpublished. But the direction is consistent. These connectivity changes appear very early, and they are different in nature from the gray matter changes that were hyped in the early literature.

Cort's analogy is physical exercise. A beginner probably does gain some muscle mass, especially starting from a deficit. But it would certainly not be linear, you would not want it to be, and in some cases you might not want any increase at all.

Most of what you actually want from exercise has nothing to do with how big the muscle is. The same holds for the brain. Not only is the gray matter science mixed, it is not even clear that growth is the thing you should hope for.

Cort points to a U-shaped curve seen with attentional networks. The true experts expend very little energy. You might not see a dramatically different brain structure, but the efficiency with which their brain operates is very different.

His comparison is a marathon runner who can hop off the couch and jog a few miles as though it were nothing, relative to a typical person.

No. Cort notes they have had this same conversation about dopamine and about the amygdala. A simplistic story takes hold in which something is good or bad, when the reality is far more nuanced.

Inflammation. Many chronic illnesses are associated with it, including autoimmune and cardiovascular disease. Many forms of meditation have an anti-inflammatory effect in the body, and Davidson says this is likely the case in the brain as well. He is deliberately careful with his wording here.

Because it is a contributory cause of premature neurodegeneration and of various types of dementia. What makes this a live area rather than a settled one is that non-invasive ways of measuring neuroinflammation in humans with MRI are only just beginning to exist.

Davidson expects the next few years in that space to be exciting.

Many years ago, after the research on meditation had started producing brain findings, the Dalai Lama told Davidson that he reflects on this while meditating, on many days. He finds it remarkable that his brain is changing as a consequence of his meditation.

Davidson's response is that this is something we all can embrace. It did not have to be this way. It was not necessarily the case that it would turn out true.

On capacity. He goes so far as to say there is very good evidence that humans have the capability for transforming their brain in a way far greater than any other species. We are given this precious gift, and the invitation running through all of Dharma Lab is to harness that gift for the good.

Cort closes on the contrast. Decades ago the science suggested we were hardwired with little room for change. What the evidence now suggests is that our biology is built for transformation.