How to Change Your Mind

by Michael Pollan

  One way to think about this blooming of mental states is that it temporarily boosts the sheer amount of diversity in our mental life. If problem solving is anything like evolutionary adaptation, the more possibilities the mind has at its disposal, the more creative its solutions will be. In this sense, entropy in the brain is a bit like variation in evolution: it supplies the diversity of raw materials on which selection can then operate to solve problems and bring novelty into the world. If, as so many artists and scientists have testified, the psychedelic experience is an aid to creativity—to thinking “outside the box”—this model might help explain why that is the case. Maybe the problem with “the box” is that it is singular.

  A key question that the science of psychedelics has not even begun to answer is whether the new neural connections that psychedelics make possible endure in any way, or if the brain’s wiring returns to the status quo ante once the drug wears off. The finding by Roland Griffiths’s lab that the psychedelic experience leads to long-term changes in the personality trait of openness raises the possibility that some kind of learning takes place while the brain is rewired and that it might in some way persist. Learning entails the establishment of new neural circuits; these get stronger the more exercise they get. The long-term fate of the novel connections formed during the psychedelic experience—whether they prove durable or evanescent—might depend on whether we recall and, in effect, exercise them after the experience ends. (This could be as simple as recollecting what we experienced, reinforcing it during the integration process, or using meditation to reenact the altered state of consciousness.) Franz Vollenweider has suggested that the psychedelic experience may facilitate “neuroplasticity”: it opens a window in which patterns of thought and behavior become more plastic and so easier to change. His model sounds like a chemically mediated form of cognitive behavioral therapy. But so far this is all highly speculative; as yet there has been little mapping of the brain before and after psychedelics to determine what, if anything, the experience changes in a lasting way.

  Carhart-Harris argues in the entropy paper that even a temporary rewiring of the brain is potentially valuable, especially for people suffering from disorders characterized by mental rigidity. A high-dose psychedelic experience has the power to “shake the snow globe,” he says, disrupting unhealthy patterns of thought and creating a space of flexibility—entropy—in which more salubrious patterns and narratives have an opportunity to coalesce as the snow slowly resettles.

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  THE IDEA that increasing the amount of entropy in the human brain might actually be good for us is surely counterintuitive. Most of us bring a negative connotation to the term: entropy suggests the gradual deterioration of a hard-won order, the disintegration of a system over time. Certainly getting older feels like an entropic process—a gradual running down and disordering of the mind and body. But maybe that’s the wrong way to think about it. Robin Carhart-Harris’s paper got me wondering if, at least for the mind, aging is really a process of declining entropy, the fading over time of what we should regard as a positive attribute of mental life.

  Certainly by middle age, the sway of habitual thinking over the operations of the mind is nearly absolute. By now, I can count on past experience to propose quick and usually serviceable answers to just about any question reality poses, whether it’s about how to soothe a child or mollify a spouse, repair a sentence, accept a compliment, answer the next question, or make sense of whatever’s happening in the world. With experience and time, it gets easier to cut to the chase and leap to conclusions—clichés that imply a kind of agility but that in fact may signify precisely the opposite: a petrifaction of thought. Think of it as predictive coding on the scale of life; the priors—and by now I’ve got millions of them—usually have my back, can be relied on to give me a decent enough answer, even if it isn’t a particularly fresh or imaginative one. A flattering term for this regime of good enough predictions is “wisdom.”

  Reading Robin’s paper helped me better understand what I was looking for when I decided to explore psychedelics: to give my own snow globe a vigorous shaking, see if I could renovate my everyday mental life by introducing a greater measure of entropy, and uncertainty, into it. Getting older might render the world more predictable (in every sense), yet it also lightens the burden of responsibility, creating a new space for experiment. Mine had been to see if it wasn’t too late to skip out of some of the deeper grooves of habit that the been-theres and done-thats of long experience had inscribed on my mind.

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  IN BOTH PHYSICS and information theory, entropy is often associated with expansion—as in the expansion of a gas when it is heated or freed from the constraints of a container. As the gas’s molecules diffuse in space, it becomes harder to predict the location of any given one; the uncertainty of the system thus increases. In a throwaway line at the end of his entropy paper, Carhart-Harris reminds us that in the 1960s the psychedelic experience was usually described as “consciousness-expansion”; knowingly or not, Timothy Leary and his colleagues had hit on exactly the right metaphor for the entropic brain. This expansion metaphor also chimes with Huxley’s reducing valve, implying as it does that consciousness exists in a state of opening or contraction.

  As a matter of experience, a quality as abstract as entropy is almost impossible for us to perceive, but expansion, perhaps, is not. Judson Brewer, the neuroscientist who studies meditation, has found that a felt sense of expansion in consciousness correlates with a drop in activity in one particular node of the default mode network—the posterior cingulate cortex (PCC), which is associated with self-referential processing. One of the most interesting things about a psychedelic experience is that it sharpens one’s sensitivity to one’s own mental states, especially in the days immediately following. The usual seamlessness of consciousness is disturbed in such a way as to make any given state—mind wandering, focused attention, rumination—both more salient and somewhat easier to manipulate. In the wake of my psychedelic experiences (and, perhaps, in the wake of interviewing Judson Brewer), I found that when I put my mind to it, I could locate my own state of consciousness on a spectrum ranging from contraction to expansion.

  When, for example, I’m feeling especially generous or grateful, open to feelings and people and nature, I register a sense of expansion. This feeling is often accompanied by a diminution of ego, as well as a falloff in the attention paid to past and future on which the ego feasts. (And depends.) By the same token, there is a pronounced sense of contraction when I’m obsessing about things or feeling fearful, defensive, rushed, worried, and regretful. (These last two feelings don’t exist without time travel.) At such times, I feel altogether more me, and not in a good way. If the neuroscientists are right, what I’m observing in my mind has a physical correlate in the brain: the default mode network is either online or off; entropy is either high or low. What exactly to do with this information I’m not yet sure.

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  BY NOW, it may be lost to memory, but all of us, even the psychedelically naive, have had direct personal experience of an entropic brain and the novel type of consciousness it sponsors—as a young child. Baby consciousness is so different from adult consciousness as to constitute a mental country of its own, one from which we are expelled sometime early in adolescence. Is there a way back in? The closest we can come to visiting that foreign land as adults may be during the psychedelic journey. This at least is the startling hypothesis of Alison Gopnik, a developmental psychologist and philosopher who happens to be a colleague of mine at Berkeley.

  Alison Gopnik and Robin Carhart-Harris come at the problem of consciousness from what seem like completely different directions and disciplines, but soon after they learned of each other’s work (I had e-mailed a PDF of Robin’s entropy paper to Alison and told him about her superb book, The Philosophical Baby), th
ey struck up a conversation that has proven to be remarkably illuminating, at least for me. In April 2016, their conversation wound up on a stage at a conference on consciousness in Tucson, Arizona, where the two met for the first time and shared a panel.*

  In much the same way psychedelics have given Carhart-Harris an oblique angle from which to approach the phenomena of normal consciousness by exploring an altered state of it, Gopnik proposes we regard the mind of the young child as another kind of “altered state,” and in a number of respects it is a strikingly similar one. She cautions that our thinking about the subject is usually constrained by our own restricted experience of consciousness, which we naturally take to be the whole of it. In this case, most of the theories and generalizations about consciousness have been made by people who share a fairly limited subtype of it she calls “professor consciousness,” which she defines as “the phenomenology of your average middle-aged professor.”

  “As academics, either we’re incredibly focused on a particular problem,” Gopnik told the audience of philosophers and neuroscientists in Tucson, “or we’re sitting there saying to ourselves, ‘Why can’t I focus on this problem I’m supposed to be focused on, and why instead am I daydreaming?’” Gopnik herself looks the part of a Berkeley professor in her early sixties, with her colorful scarves, flowing skirts, and sensible shoes. A child of the 1960s who is now a grandmother, she has a speaking style that is at once lighthearted and learned, studded with references indicating a mind as much at home in the humanities as the sciences.

  “If you thought, as people often have thought, that this was all there was to consciousness . . . you might very well find yourself thinking that young children were actually less conscious than we were,” because both focused attention and self-reflection are absent in young children. Gopnik asks us to think about child consciousness in terms of not what’s missing from it or undeveloped but rather what is uniquely and wonderfully present—qualities that she believes psychedelics can help us to better appreciate and, possibly, reexperience.

  In The Philosophical Baby, Gopnik draws a useful distinction between the “spotlight consciousness” of adults and the “lantern consciousness” of young children. The first mode gives adults the ability to narrowly focus attention on a goal. (In his own remarks, Carhart-Harris called this “ego consciousness” or “consciousness with a point.”) In the second mode—lantern consciousness—attention is more widely diffused, allowing the child to take in information from virtually anywhere in her field of awareness, which is quite wide, wider than that of most adults. (By this measure, children are more conscious than adults, rather than less.) While children seldom exhibit sustained periods of spotlight consciousness, adults occasionally experience that “vivid panoramic illumination of the everyday” that lantern consciousness affords us. To borrow Judson Brewer’s terms, lantern consciousness is expansive, spotlight consciousness narrow, or contracted.

  The adult brain directs the spotlight of its attention where it will and then relies on predictive coding to make sense of what it perceives. This is not at all the child’s approach, Gopnik has discovered. Being inexperienced in the way of the world, the mind of the young child has comparatively few priors, or preconceptions, to guide her perceptions down the predictable tracks. Instead, the child approaches reality with the astonishment of an adult on psychedelics.

  What this means for cognition and learning can be best understood by looking at machine learning, or artificial intelligence, Gopnik suggests. In teaching computers how to learn and solve problems, AI designers speak in terms of “high temperature” and “low temperature” searches for the answers to questions. A low-temperature search (so-called because it requires less energy) involves reaching for the most probable or nearest-to-hand answer, like the one that worked for a similar problem in the past. Low-temperature searches succeed more often than not. A high-temperature search requires more energy because it involves reaching for less likely but possibly more ingenious and creative answers—those found outside the box of preconception. Drawing on its wealth of experience, the adult mind performs low-temperature searches most of the time.

  Gopnik believes that both the young child (five and under) and the adult on a psychedelic have a stronger predilection for the high-temperature search; in their quest to make sense of things, their minds explore not just the nearby and most likely but “the entire space of possibilities.” These high-temperature searches might be inefficient, incurring a higher rate of error and requiring more time and mental energy to perform. High-temperature searches can yield answers that are more magical than realistic. Yet there are times when hot searches are the only way to solve a problem, and occasionally they return answers of surpassing beauty and originality. E=mc2 was the product of a high-temperature search.

  Gopnik has tested this hypothesis on children in her lab and has found that there are learning problems that four-year-olds are better at solving than adults. These are precisely the kinds of problems that require thinking outside the box, those times when experience hobbles rather than greases the gears of problem solving, often because the problem is so novel. In one experiment, she presented children with a toy box that lights up and plays music when a certain kind of block is placed on top of it. Normally, this “blicket detector” is set to respond to a single block of a certain color or shape, but when the experimenter reprograms the machine so that it responds only when two blocks are placed on it, four-year-olds figure it out much faster than adults do.

  “Their thinking is less constrained by experience, so they will try even the most unlikely possibilities”; that is, they’ll conduct lots of high-temperature searches, testing the most far-out hypotheses. “Children are better learners than adults in many cases when the solutions are nonobvious” or, as she puts it, “further out in the space of possibilities,” a realm where they are more at home than we are. Far out, indeed.

  “We have the longest childhood of any species,” Gopnik says. “This extended period of learning and exploration is what’s distinctive about us. I think of childhood as the R&D stage of the species, concerned exclusively with learning and exploring. We adults are production and marketing.” Later I asked her if she meant to say that children perform R&D for the individual, not the species, but in fact she meant exactly what she said.

  “Each generation of children confronts a new environment,” she explained, “and their brains are particularly good at learning and thriving in that environment. Think of the children of immigrants, or four-year-olds confronted with an iPhone. Children don’t invent these new tools, they don’t create the new environment, but in every generation they build the kind of brain that can best thrive in it. Childhood is the species’ ways of injecting noise into the system of cultural evolution.” “Noise,” of course, is in this context another word for “entropy.”

  “The child’s brain is extremely plastic, good for learning, not accomplishing”—better for “exploring rather than exploiting.” It also has a great many more neural connections than the adult brain. (During the panel, Carhart-Harris showed his map of the mind on psilocybin, with its dense forest of lines connecting every region to every other.) But as we reach adolescence, most of those connections get pruned, so that the “human brain becomes a lean, mean acting machine.” A key element of that developmental process is the suppression of entropy, with all of its implications, both good and bad. The system cools, and hot searches become the exception rather than the rule. The default mode network comes online.

  “Consciousness narrows as we get older,” Gopnik says. “Adults have congealed in their beliefs and are hard to shift,” she has written, whereas “children are more fluid and consequently more willing to entertain new ideas.

  “If you want to understand what an expanded consciousness looks like, all you have to do is have tea with a four-year-old.”

  Or drop a tab of LSD. Gopnik told me she has been struck by the similariti
es between the phenomenology of the LSD experience and her understanding of the consciousness of children: hotter searches, diffused attention, more mental noise (or entropy), magical thinking, and little sense of a self that is continuous over time.

  “The short summary is, babies and children are basically tripping all the time.”

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  SURELY THIS INSIGHT is interesting, but is it useful? Both Gopnik and Carhart-Harris believe it is, believe that the psychedelic experience, as they conceptualize it, has the potential to help people who are sick and people who are not. For the well, psychedelics, by introducing more noise or entropy into the brain, might shake people out of their usual patterns of thought—“lubricate cognition,” in Carhart-Harris’s words—in ways that might enhance well-being, make us more open and boost creativity. In Gopnik’s terms, the drugs could help adults achieve the kind of fluid thinking that is second nature to kids, expanding the space of creative possibility. If, as Gopnik hypothesizes, “childhood is a way of injecting noise—and novelty—into the system of cultural evolution,” psychedelics might do the same thing for the system of the adult mind.