Because of the similarity of the last names, we are using full names to identify interviewer and interviewee.

— Ed.


Cognitive psychologist and neuroscientist Daniel J. Levitin has spent almost three decades studying the power of the human brain — from how memory works to how we can make good decisions in an age of information overload. In his most recent book, Successful Aging, he discusses strategies for maintaining mental vitality in our old age. They include taking walks, getting better sleep, and trying new things. They don’t include constantly checking e-mail, Twitter, and Facebook, which he describes as a “neural addiction.”

Before earning his degrees in the science of the brain, Levitin worked as a musician and record producer in his hometown of San Francisco in the 1970s and 1980s, but he was interested in learning more about what lay beneath the creative process. He earned a PhD in cognitive psychology from the University of Oregon in 1996, and after completing his postdoctoral training in neuroimaging and perception at the University of California, Berkeley, and Stanford University School of Medicine, he pioneered the field of “neuroaesthetics” — the study of how the brain delivers aesthetic experiences. His first two books, This Is Your Brain on Music and The World in Six Songs, both became best sellers. He believes making musical sounds may have prepared our prehuman ancestors for using speech.

For many years Levitin ran the Laboratory for Music Perception, Cognition, and Expertise at McGill University in Montreal, Canada. He’s taught at Stanford and been a visiting professor at Dartmouth and UC Berkeley. In 2013 he became the founding dean of arts and humanities at the Minerva Schools at the Keck Graduate Institute in San Francisco (now Minerva University). He has performed with Sting, David Byrne, and Rosanne Cash, and worked on albums with Stevie Wonder, Steely Dan, and Carlos Santana.

Now in his midsixties, Levitin lives in Los Angeles with his wife, Heather, and maintains friendships with colleagues in both science and the arts, including Nobel Prize–winner David Baltimore and musician Joni Mitchell. We talked by video chat, bonding over our mutual love of music before moving on to discuss psychology, brain science, and cultural history.


A photograph of Daniel J. Levitin.


© Larry Moran

Mark Leviton: Let’s start with how the brain functions. Most laypeople think information reaches us through our senses, and then our brain sorts it and files it away as memory, but Roger Shepard, your teacher at Stanford, said a properly functioning brain is supposed to “distort the world we see and hear.” What did he mean? Are our senses untrustworthy?

Daniel Levitin: First let me say that all of us have what you might call folk theories about how things work, and in some cases those theories are borne out. My grandmother was always pushing chicken soup as a cure for any illness, and just in the last year experiments have shown that the combination of fats, salts, and liquid in chicken soup serves as a rehydration solution. So it’s often the case that scientists and doctors are playing catch-up.

The process of interpreting the information received by the senses is very complex. A lot of what used to be called psychology is now studied by neuroscience. Evolutionarily speaking, we need certain information in order to locate food and water and shelter and to find protection from predators, and we sort that information into categories to survive. But we also need to be aware that different objects can create nearly identical patterns of stimulation on our retinas, eardrums, or taste buds. The apple I saw on a tree yesterday may look like the one I’m holding in my hand today, but they are different apples. In addition, our brain must integrate seemingly disparate images: an elephant looks different from the side and from behind, but we recognize it as the same animal from both angles.

Seeing and hearing are selective. We register what is needed at the moment and unconsciously ignore other input. It may seem that our eyes are like a camera and our ears are like microphones, objectively recording everything, but we know from fifty years of experiments that our senses are not at all like those devices.

Not only that, if we examine how information makes its way from the world, to our sensory receptors, and then into our brain, we see that a lot gets lost, and there’s a lot of distortion. People don’t like to believe this, so psychologists show them demonstrations. Intro psych classes in college are pretty much devoted to demonstrating that you don’t know what you think you know!

We’ve all had the experience of reading and getting to the end of a sentence and realizing it doesn’t make sense. Then we go back and find the word we saw wrong. Misreading or mishearing is often the result of unconscious expectations. We thought the sentence would say something different before we even read it.

Here’s another example: Say I’m a radar operator, and when I take over the radar station, I’m told, “There’s nobody within five hundred miles of here, so you’ve got an easy night ahead of you.” If that’s my expectation, I’ll wait longer to press the alarm button, which can be very important to avoid unnecessarily placing everyone on the submarine into crisis mode when one doesn’t exist.

In daily life, if you’re driving on the freeway and you’re the only car there, you’re not going to be as vigilant. If, on the other hand, you’re expecting a lot of potholes, you might overreact, thinking that a shadow is a hazard.

What you experience over the course of a lifetime informs your expectations, and that’s where we get unconscious racial bias. If you’re a cop and you’ve had lots of confrontational experiences with people of color in the past, you’re going to behave differently than if you’ve had more benign interactions. You’re treating the person in front of you not as an individual but as kind of a number in a skewed statistical sample.

Mark Leviton: There’s a famous experiment where subjects are asked to watch a video of six people playing basketball and to keep a silent tally of how many times players wearing white shirts pass the ball. In the middle of the game someone in a gorilla suit enters the frame, faces the camera for nine seconds thumping his chest, and exits. When the video ends, about half of the subjects have no idea a gorilla appeared.

Daniel Levitin: Likewise you can show people a scene, remove something, and show it again, and they will report that what you removed is still there.

My favorite demonstration of this is called the “phoneme restoration effect.” It was reported in 1970 by Richard Warren of the University of Wisconsin–Milwaukee, who recorded a sentence — “The state governors met with their respective legislatures convening in the capital city” — and then took out the first s in legislatures and replaced it with the sound of a cough. Out of twenty subjects, nineteen didn’t hear the cough and reported nothing wrong with the way legislatures sounded. When the experiment is repeated, even people who hear the cough mostly misidentify where it occurs. The subjects’ brains fill in the missing s, providing what was needed for intelligibility rather than what actually happened aurally. Neuroscientists call this “top-down processing”: the brain supplies the ears with what it thinks they require.

Mark Leviton: You say the brain is an excellent “change detector”: it notices “novelty,” variations from the norm.

Daniel Levitin: Ultimately there are two forces at work. One is that the brain is a prediction device. All organisms need to prepare for what’s going to happen next, and they do that by trying to recognize patterns in the world, whether auditory, visual, tactile, or even — if you’re a migratory bird, for instance — magnetic.

When things are predictable, we take less notice of them. This is why, if you’ve lived for years with a noisy refrigerator, you don’t notice it anymore. Then your friends come over and say, “Boy, that’s a noisy fridge!” We habituate to things over time.

But the brain is always on the lookout for change, because a change could mean a new opportunity — a new food source maybe — or a danger: an unfamiliar sound could indicate an avalanche is coming.

As we experience more things in life, we come to consider some things that are actually different to be pretty much the same. If I’m a young child who’s focused on every little detail, this blanket is not just any blanket; this is my blanket. No other blanket will do. Or I might have a hundred dolls on my bed, but if I can’t find my favorite doll, I’m freaking out. As we age, unless we’re on the autism spectrum, we tend not to notice every little difference between this item and that item, as long as they serve the same purpose.

Mark Leviton: You write about different types of memory: semantic memory versus episodic memory, for example. Are these different ways of deciding what memories are real?

Daniel Levitin: Semantic memory holds your knowledge of facts and figures. Episodic memory is the remembering of a “specific event,” which I put in quotes, because we often misremember certain attributes of it. Memory is very complex.

When Paul McCartney and George Harrison of the Beatles got together to work on the Anthology project in the nineties, their memories of who’d played what and when were often completely incompatible. In many cases the logs of the recording sessions told a third story. If you care about pop music, like you and I do, this is important stuff!

An example of a semantic memory would be if you know Denver is the capital of Colorado. An episodic memory would be if you can recall when and where you learned that fact. You can see how this is related to the concept of “differences that make a difference and differences that don’t.” In most cases it doesn’t matter where I learned something like the capital of Colorado. But if somebody tells me that Trump really won the 2020 election, and then somebody else tells me Biden won, to sort out who’s telling the truth I might use episodic memory: Who told me what, when, and what biases might they hold? It’s complicated.

Mark Leviton: Our brains evolved to deal with a tribal, hunter-gatherer culture, not the supercomplex civilization we’ve constructed. Has there been enough time for our brains to catch up to modern life?

Daniel Levitin: You’re talking about “evolutionary lag,” the idea that it can take ten thousand years for our genes to catch up with present living conditions. My friend and colleague Robert Sapolsky at Stanford talks about this concept. The human genome is constantly changing. There’s the possibility of a random mutation with every birth. And random mutations can bring about sudden modifications, as predicted in the original Darwinian model.

Sapolsky also points out that genomes can change quickly in response to environmental conditions. During the height of the mid-nineteenth-century industrial revolution in England, for example, people noticed that previously common white moths were becoming rarer, while the population of black moths grew larger. A hundred years later, at Oxford University, Bernard Kettlewell showed how the increased pollution of the 1850s made white moths more vulnerable to predation by birds: they stood out against the newly blackened background. Black moths, being better camouflaged, survived better and thus had more progeny. This resulted in a rapid change in the moth genome. Sapolsky and others are searching for similar changes in the human genome that might have occurred more rapidly than we thought possible. So it might not take ten thousand years for the human genome to react to cell phones and computers.

Mark Leviton: Could alterations to the human genome be triggered by cataclysmic social events?

Daniel Levitin: Let’s look at the Holocaust. A third of all the Jews on the planet were killed. But some Jews got out of Europe before, during, and after World War II. My mother got out. Her sisters and her mother got out. The rest of their family didn’t.

Here’s a thought experiment: Suppose there was a personality difference that helped some Jews get out. Suppose they were just a little pushier or a little more paranoid or a little better at thinking ahead. Whatever that personality characteristic is, it might have given them an elevated chance to escape. They would then be more likely to pass on the genes for that characteristic. And the people who didn’t have that combination of genes would have been more likely to die. That’s a potential genetic change in the population of the Jewish people that could have taken place in fifty years, not ten thousand.

Memories aren’t actually stored in the hippocampus the way you might store a book on a shelf. In the library of the brain, I think the hippocampus is the card catalog that tells you what shelf the memory is on.

Mark Leviton: Let’s get back to talking about how human brains function. You make a distinction between two types of memory retrieval, one that involves place — Where did I leave my car keys? — and one that doesn’t: What’s my PIN number?

Daniel Levitin: Our memory is largely served by a brain structure called the hippocampus, which is shaped somewhat like a seahorse. It’s in both halves of the brain, deep down inside, and it arranges the storage of short- and long-term memory, including the connection of certain sensations and emotions to those memories.

I’ve come to believe that memories aren’t actually stored in the hippocampus the way you might store a book on a shelf. In the library of the brain, I think the hippocampus is the card catalog that tells you what shelf the memory is on, in which wing of the library.

The hippocampus evolved in humans and other mammals to help us find things: Where’s the water? Where’s the food? Where’s the shelter? This was all place memory and extremely important. Neuroscientists have found the hippocampi of London taxi drivers increase in size as they learn more locations in the city. The hippocampus isn’t ideal for remembering things like your PIN number or the lyrics to a song, but we use it for those tasks anyway.

In just the last five years or so we’ve learned that the best way to improve your general memory is to exercise your geonavigation skills. Go for a walk, especially on an uneven surface where you have to negotiate obstacles like tree roots or holes. Or go to a place you haven’t been before. If you’re not in a hurry, turn off the GPS in your car. All of this strengthens the functioning of the hippocampus.

Mark Leviton: I’m sixty-eight years old, and my memory isn’t as good as it once was. Is there anything else I can do to stop the decay of my gray matter?

Daniel Levitin: Yes and no. So far there’s no way to cure dementia, but you can slow down the symptoms. The way you do that is by building up cognitive reserves. Your brain can get stronger, until it’s like a marathon runner who, even on a bad day, can still easily run six miles. Engaging with new people, taking on new tasks, and learning new things all build neural pathways and connections. We have that ability for our entire lifetime. And new information doesn’t displace old information. On an episode of The Simpsons, Homer said he couldn’t learn anything new: if he took a wine-making class, he’d forget how to drive a car. That’s not how it works. Nobody’s documented any individual who could no longer learn something new, unless that person had a severe brain injury.

When you can’t recall something, it’s not that your memory has failed. In almost every case, that name that you were struggling to remember eventually comes. The vast majority of older Americans don’t have actual memory loss. What they’re complaining about is the slowing down of the retrieval mechanism. It shouldn’t have taken me half an hour this morning to think of the name “Bill Monroe,” but I hadn’t thought of Bill Monroe in a couple of years, so retrieval suffered a bit.

We all have memory lapses throughout life. You’re going to lose your keys occasionally. One way to avoid that is to put external systems in place that will help you remember. The psychologist B.F. Skinner used to say that if he heard it was going to rain the next day, he’d take the umbrella from the closet and hang it on the front doorknob. Then, when he left the house in the morning, he wouldn’t have to remember the weather report.

Mark Leviton: But where, exactly, is the memory? It’s got to have some kind of physical existence, doesn’t it? I’m not just making it up every time. I’m looking for it in some location in my brain, no?

Daniel Levitin: It’s not in a place. Most likely it’s in a distributed network of neurons. It’s like asking, “Where is the gravity in my house?” It’s not in any one spot. It’s distributed. Or, “Where is the University of California?” Well, I can circle the campus on a map, but during the pandemic nobody was there. Yet the “University of California” still existed as a network of people.

Mark Leviton: Sometimes a memory gets triggered by a certain smell, or a texture, or a color. What’s happening there?

Daniel Levitin: Let’s take a point of mutual interest for you and me: Say I hear a new John Fogerty song for the first time. There’s this particular network of neural circuits that’s responding in my brain. There’s part of the brain that is extracting the pitch of the notes, then passing information to another circuit that creates some representation of the melody. A separate part is extracting the duration of the notes. The duration circuits pass information to an area that puts together a sense of rhythm and tempo. Then there’s the timbre, which is what gives a sound its particular signature. It’s how we identify a note played on a guitar versus the same note played on a banjo. That unmistakable quality of Fogerty’s voice comes from the timbre and is as distinctive as a fingerprint.

My research shows that these processes are happening in different parts of the brain, not a single area where something called “music” is processed. The various qualities of a sound — loudness, pitch, timbre, duration — are each handled in the area of the brain most suited to them, then brought together to create what I recognize as a John Fogerty song. I can do that, even though I’ve never heard this particular tune before, because there are also circuits connecting the experience to my memory of other Fogerty songs, comparing what’s similar and what’s different, and connecting Fogerty’s voice to how he makes me feel. I’ve got a memory of sitting in my bedroom in sixth grade listening to a record of him singing “Down on the Corner” with Creedence Clearwater Revival.

When I simply imagine a song without hearing it, what appears to be happening is that the hippocampal index tells me, These are the circuits that were involved, the neurons that fired, the firing rates of those different neurons — all of that info on the library cards I described. But I don’t get it back perfectly.

Remembering is the process of reassembling the elements of the neural circuit that was created during your first experience, which you do in real time in the present moment. It’s not the retrieval of a static information set but a sometimes flawed re-creation of interpreted experience.

Mark Leviton: This leads us into the subject of false memory. Psychology experiments and brain imaging have demonstrated that people will “remember” events that did not take place.

Daniel Levitin: The reality is we have false memories every day, lots of them. We just don’t know it, because we’re not often challenged. Of course, the place with the highest stakes is the courtroom. Not all eyewitnesses are reliable, but you can’t know which ones are and which aren’t. That’s why, generally speaking, you want three witnesses, but prosecutors often must base a case on one. And even with multiple witnesses, false memories can creep in for all of them.

Here’s an example that involves millions of people: A clear majority of Americans who lived through September 11, 2001, recall falsely that they saw footage of the first tower being hit by a plane that day. We all saw the second plane hit, but no media outlets had footage of the first until the following day, when bystander videos made it onto the airwaves. On that day, September 12, networks and other news sources showed the footage to you in order — the first plane hitting, then the second.

As we’ve discussed, the brain is not as interested in how it comes to acquire information as it is in interpreting that information in the most helpful way. And so most Americans’ brains overwrote the true sequence of events and constructed a “corrected” version. Millions of people will swear that on September 11 they saw the first plane hit. It’s a collective illusion.

The best way to improve your general memory is to exercise your geonavigation skills. Go for a walk. . . . If you’re not in a hurry, turn off the GPS in your car. All of this strengthens the functioning of the hippocampus.

Mark Leviton: How does the actual process of encoding memories work?

Daniel Levitin: There are three steps that go into a memory: first you experience something, then you encode that experience, and finally you reencode it.

How we “experience something” varies. Say I walk into a house that I’m thinking of buying: I’m going to notice different things than if I were thinking of robbing it. As a buyer I don’t care about the expensive coin collection in the glass case; I care about the leaky roof.

Not everything we experience makes it into memory. If I am really paying attention, the experience is much more likely to be encoded. Also the things you care about or that have some emotional quality will probably be encoded in memory. Often the unconscious is deciding: What does this experience mean to me? What might I learn from this? How can I use this later? Or maybe there’s some deliberate encoding going on during the experience: If I’m a thief walking through a house, I’m thinking, I’m going to steal that, and I’m going to steal that — oh, be careful, there’s a dog living here!

Sleep is when much of the reencoding, the deep memory storage, happens. If you don’t get sufficient sleep after you’ve learned something, it’s unlikely to get into memory. So when you were in college and stayed up all night studying, that was a bad idea. You have to sleep, because that’s when your brain is tossing and turning around the information that you acquired during the day and tagging it in such a way that it’s linked to other things. If you smell something today and recall a memory from thirty years ago, it’s because thirty years ago that scent and that experience were tagged together while you slept.

Mark Leviton: Is lack of sleep a big deterrent to, for instance, remembering the names of people who you’ve just been introduced to at a party?

Daniel Levitin: Well, that might be a short-term memory lapse, which is a somewhat different problem. But if I meet you today and don’t pay attention to your name, I probably won’t remember it tomorrow. And if there’s alcohol involved, I’m less likely to recall it. Drinking impairs memory and impairs sleep.

In most cases it’s not that I forgot the name itself. I know, for instance, the name Mark. I just didn’t associate the name with your face. The link is what wasn’t encoded.

Mark Leviton: Self-help books recommend repeating someone’s name when you’re introduced: “Nice to meet you, Bob!” My problem is I keep forgetting to do that. [Laughs.]

Daniel Levitin: I mentioned reencoding a moment ago as something that happens during sleep, but it also happens when we’re awake. This has been studied by Karim Nader at McGill University, whose findings inspired the film Eternal Sunshine of the Spotless Mind. The idea is that every time you recall a memory, it can be rewritten. There are lots of demonstrations showing that if I pull out a memory and I’m in a bad mood, it can get put back differently, either improving or undermining its veracity, depending on what actually happened.

Mark Leviton: I have a strong memory, from about the age of eight, of listening to my younger sister being spanked. Nothing like that had ever happened before, and it never happened again. When I mentioned it to my sister much later in life, she gave me a funny look and said I was the one who’d been spanked.

Daniel Levitin: Elizabeth Loftus at the University of California, Irvine, has studied this phenomenon extensively. In one experiment she showed subjects video of a traffic accident and had them estimate the speed of the cars at impact. A week later she brought them back to the lab and again asked them to estimate how fast the vehicles had been going, but this time she changed a single word in the question: “How fast do you think the cars were going when they smashed into each other?” instead of “when they hit each other?” That simple substitution caused the subjects to increase their estimate of how fast the cars had been going.

The clincher was when she asked them whether they’d seen broken glass in the video. There was none, but those who estimated speed based on “smashed” more often reported seeing broken glass. And they stuck to their story. Loftus has made a career out of showing how police interrogations can alter witnesses’ memories and actually distort the truth.

So, if your sister is right, how could you misremember something like the spanking? Part of it is that, when we originally encode or reencode memories, there are psychological factors. Maybe you wanted to save face. Or maybe when you got spanked, you were focused on the fear that this could happen to your sister. You wanted to protect her. The thoughts and emotions that you have about the event can become enmeshed with the event itself, so that you misremember it.

If you don’t get sufficient sleep after you’ve learned something, it’s unlikely to get into memory. So when you were in college and stayed up all night studying, that was a bad idea. You have to sleep.

Mark Leviton: We’ve talked about how sleep is crucial for encoding memories, but you also write about the value of daydreaming. You quote neurologist Marcus Raichle, who proposes that the default mode of our brain is actually the “wandering mind.”

Daniel Levitin: The scientific literature refers to the “default mode” and the “central-executive mode.” Central-executive mode is used when you’re engaged in a task, focused on getting things done. But after you’ve been doing that for a while, your brain gets tired and starts to daydream. That’s the “default mode.” I don’t particularly like that term, so I call it the “daydreaming mode,” which comes closer to Marc’s conception of it. (By the way, Marc is a great violinist.)

These are not the only modes of consciousness, obviously. There’s the meditative state. There’s semiconsciousness. There’s sleep. But these are the two primary modes, and they function like a teeter-totter: when one goes down, the other goes up. The central executive is good for problem solving when the problem has a rational and linear solution, and the daydreaming mode is better when the solution requires you to think outside the box, find some connection between things that isn’t linear or obvious. A lot of art and creativity occurs in that mode. I don’t think Joni Mitchell wrote her song “Amelia” just by sitting at a desk and writing music and lyrics in a linear fashion. Perhaps she used the central-executive mode when she spent months editing it and shaping it for performance, but I don’t think that’s where the song came from. I don’t think the Sistine Chapel ceiling came from the deliberate application of pure logic, where A connects to B connects to C.

My experience, in making music myself and in studying creativity, tells me both modes are necessary to implement an artistic idea. There’s always discipline and craft combined with artistic inspiration. Neil Young has told me that he wrote every song he’s ever written in less than fifteen minutes, never going back to edit, but there aren’t many songwriters like him.

Mark Leviton: I suspect he’s exaggerating a bit. He’s also said that whenever he gets a creative idea, even an inkling, he’ll stop whatever he’s doing and run off to follow it. He thinks if you don’t jump up and attend to it, it’ll be lost.

Daniel Levitin: The daydreaming mode is at work when you’re walking down the cereal aisle at the grocery store, and you’re kind of zoned out, then suddenly — this problem you’re having at work: you’ve figured out the solution!

We used to call the daydreaming mode the subconscious, but subconscious and unconscious are not well-defined terms. The current view is that consciousness is not binary, on or off. It’s a continuum. I’ve come to think that, if I lose my reading glasses, maybe the part of me that set them down was asleep. Sleep is not all or nothing. Consciousness is not all or nothing. I’m sure right now there are parts of my brain that are off-line, taking a snooze.

Mark Leviton: I daydream a lot, so I’m encouraged by the thought that I’m not just wasting my time. Let me ask you about something else: Before artificial light was invented, human activities were organized around the sun coming up and going down. How have we adapted to modern life, where we may eat, work, and sleep on schedules that aren’t influenced by the sun or the seasons?

Daniel Levitin: This is a controversial area where experts disagree. What I wrote about it in Successful Aging was vetted by scientists who are experts in circadian cycles and such, but after publication I heard from other experts who took me to task for spreading what they felt was misinformation. That’s the way science works — the evidence is sometimes confusing, and the kind of evidence that I might consider to be rigorous, another scientist won’t, and vice versa.

The story of sleep is that a shift took place historically, but the records aren’t conclusive as to when. It may have started with the invention of the electric lightbulb, or it may have begun much earlier. It appears that for thousands of years we slept in two segments: we would go to bed after dinner, sleep for a few hours, be up between midnight and four, and then go to bed again. The idea was to be awake in the middle of the night to be vigilant. The technical term for this is “biphasic sleep.” For a long time it was just taken for granted that was how you did it, so nobody bothered to write about it. There are tantalizing references to “the second sleep” here and there, but nothing definitive. By 1920 or so biphasic sleep had pretty much disappeared. The historian Roger Ekirch thinks it started to phase out much earlier, in the seventeenth century.

I think the brain doesn’t like change. It prefers that you eat at the same time every day and go to sleep at the same time every night. You have these chemical cycles that synchronize. Your body wants to get stomach acid and digestive juices ready at certain times, rather than just when you’re hungry. Light exposure in the morning triggers the release of cortisol, which increases during the day. Your body will start releasing the sleep hormone melatonin about twelve to fourteen hours after that initial cortisol surge. So if you’re used to arising at 7 AM but get up at 5 AM for an overseas Zoom meeting, your body will release melatonin a couple of hours early that evening.

Most sleep experts advise that you run a two-week test on yourself: Don’t drink any alcohol. Go to bed when you’re tired. Don’t set an alarm. Take naps if you want one. In the last two or three days of that fourteen-day period, look at what time you’re going to sleep and waking up, and that’s how much sleep you need. In general it turns out to be eight hours of actual sleep, and they will advise you to set aside nine hours in bed to get that full eight hours.

My neurologist, on the other hand, thinks that we tend to sleep too much and says seven hours in bed — not necessarily even seven hours of sleep — is just fine. He believes that beyond that, sleep isn’t restorative and causes us to reach a point of sleep inertia, where it’s harder to wake up. I can’t say whether he’s right or wrong.

Mark Leviton: It seems to me that neuroscience has taken over the field of psychology. There have been problems replicating some of the primary psychology experiments of the fifties, sixties, and seventies — the ones that defined the baselines for human behavior. What I learned in Psychology 101 in 1970 now seems much more speculative than scientific. In contrast, neuroscience is so concrete: we can see the electrical activity of the brain.

Daniel Levitin: Well, even though I’m a neuroscientist, I’d like to push back on that. I agree there has been what we might call a “neuralization” of psychology, but the leading psych departments in the world still teach a lot of the same material that you learned at UCLA. They still teach social psychology and intergroup behavior and personality and individual differences. They still teach memory and attention and decision-making and categorization and psychopathology.

The current focus on neurons was given a big boost by Marcus Raichle, who pioneered neuroimaging. And now we’ve got people at UCLA who, in addition to doing psychology as usual, are also using neuroimaging studies to determine, for example, how two subjects feel about one another. Barry Komisaruk at Rutgers studies orgasms in the scanner. An orgasm, it turns out, stimulates thirty different regions of the brain. As you might expect, the regions involved with the sense of touch are activated, but so are regions dealing with judgment and memory.

But I don’t see how neuralization makes psychology more rigorous or concrete. At best, neuroimaging is one measure. You still want to show evidence in other ways. In every case where I’ve done a brain-scan study, it wasn’t satisfying to me by itself. I don’t think it would be satisfying to most brain researchers to say, “The brain is doing this, so this person must be feeling happy.” I want to hear it from the subject. Is the person feeling happy? What kind of happy? How happy on a scale of one to ten? There are a lot of bad neuroimaging studies, a lot of false claims. We should continue to use more than one method to understand human behavior.

Mark Leviton: What about the discovery, through brain imaging, of mirror neurons, which fire both when we perform an action, like smiling, and also when we see another person perform the same action? They play an important role in our social life, allowing us to reflect body language and emotions.

Daniel Levitin: Unfortunately the whole mirror-neuron story remains controversial, and we haven’t seen solid evidence that they exist in humans. But I will agree: neuroimaging has shown us things we couldn’t see otherwise. With neuroimaging I can do something that I think will make you happy and then study your brain’s reaction and infer that this part of your brain becomes activated when you feel happy. If the same thing happens with a hundred other people, I might think I know where the happiness center of the brain is.

But to say that I don’t need to know anything else — that every time that part of the brain lights up, it must mean you’re happy — feels a bit circular. And I concluded that part of the brain is the happiness center only because people reported they felt happy. So I’m not going to tell you you’re happy because of what I see on a scan.

Mark Leviton: Let’s talk about some of the organization techniques you describe in The Organized Mind.

Daniel Levitin: This goes back to the daydreaming and central-executive modes. While you focus on one project, the mind starts distracting you with all the other things you’re not doing. Efficiency expert David Allen says the way to deal with this is to write down a list of everything you need to do, to get that voice out of your head, since you’re not going to make any progress on project B while you’re in the middle of project A.

This is supported by neurology. We toss untethered thoughts around our minds in what cognitive psychologists call a “rehearsal loop” — a network of brain regions that ties together the frontal cortex and the hippocampus. This loop evolved in a world with no writing, and for ten thousand years it helped us remember things. But in the world of smartphones and home computers, it works too well, keeping ideas swirling around in our heads until we deal with them. It turns out that writing down tasks gives the rehearsal loop permission to let go.

So write down what’s in your head. Put appointments and tasks on your calendar. Make plans.

Mark Leviton: You say multitasking, from a brain-function perspective, is actually an illusion.

Daniel Levitin: Right. You may think that you’re doing a bunch of things simultaneously — driving a car, listening to the radio, checking the GPS — but you’re not. Instead your brain is shifting from one to another. It does it so rapidly and, under normal circumstances, relatively seamlessly, that you don’t notice the switching. Earl Miller at MIT, one of the world’s experts on divided attention, says our brains are not wired to multitask.

Furthermore the switching comes at a neurobiological cost. It uses up the resources of the brain. You’re burning oxygenated glucose, which you need to stay on task. All this switching can cause you to make bad judgments.

I know people who multitask feel like they’re getting a lot done, and there’s probably some neurochemical reward for doing all these things, but it’s an illusion. The human brain can’t really attend to more than a couple of things at once. Have you ever tried to carry on two independent conversations at the same time? It’s very difficult. It’s no wonder we have so much conflict in the world: you can’t listen to two people at the same time, much less 7.9 billion.

And task-switching is stressful. Cortisol, the stress hormone, can help motivate us in small amounts, but large amounts of it are harmful. Chronic stress leads to impaired immune function and impaired digestive function, which is why, when you’re stressed, you get gastrointestinal problems.

Mark Leviton: Any parent of a teenager knows kids love to watch television or listen to music while doing homework. They claim it helps their concentration.

Daniel Levitin: They’re wrong. Not only are they impairing their ability to remember the material they’re studying, but studies show information is actually being deposited in the wrong lobe of the brain. My colleague Russ Poldrack at Stanford has found that when students study and watch TV at the same time, the information goes into the striatum, a region for storing new skills and procedures, not facts and ideas. Without TV it goes into the index of the hippocampus, where it belongs.

The consequences for both adults and kids who had to spend many months in lockdown are going to last for years. This will be a collective trauma easily on a par with the Great Depression or World War II.

Mark Leviton: Before we conclude, I’d like to get your opinion on how we have been relating to people during the pandemic through social networks and Zoom and other kinds of distant connections. As a psychologist, do you think permanent changes will come out of this, alterations to how humans interact with each other?

Daniel Levitin: I find Zoom stressful. Every professor I know finds it a very unnatural way to relate to people. Oddly it creates more sense of distance. My best friend and I still prefer to talk on the phone, ear to ear. I realize video chat includes some body language, but it’s very difficult to make eye contact. It’s unnatural from an evolutionary standpoint, the two-dimensional nature of the image. Still, during the pandemic it’s best to be in touch with other people, however you accomplish it.

During the pandemic everybody’s slowed down, and not in a good way. We’re getting less done. We are less efficient. I think many observers would have predicted, in early 2020, that schools and jobs would be more efficient without all the gathering and travel back and forth, but during lockdown even those of us who were accustomed to working at home didn’t have places to go. Many of us were getting our groceries delivered. We had more unstructured time to ourselves, but I can’t think of a single person who feels that they are getting as much done post-lockdown as they did before.

There’s a widespread lethargy. Things I used to be able to do in an hour take most of a day. I suspect the industrialized world is suffering a kind of collective, chronic, low-grade depression due to uncertainty about the future, worries about health and financial stability, changes in job status and relationship status, and lack of sleep. Many Americans are suffering from “coronasomnia.” The Centers for Disease Control and Prevention found the prevalence of depressive disorder was about four times higher in 2020 than in 2019.

I think the consequences for both adults and kids who had to spend many months in lockdown are going to last for years. This will be a collective trauma easily on a par with the Great Depression or World War II. And it will have repercussions for a long, long time. A major shift to home-based work isn’t a good idea for a lot of human-relations reasons. People need to be in each other’s presence, looking into each other’s eyes.

But I recognize it’s not an all-or-nothing thing. In the prepandemic world I flew to Germany for a two-hour meeting. I flew to New York City to appear for six minutes on CBS This Morning. With video-conferencing options, which are getting more sophisticated, we’ll reduce our carbon footprint and avoid jet lag.

But there’s no way I would give up the chance to meet with the Dalai Lama in person, as I did in August of 2019. I’d say being with him in person was really necessary.

In 2013 I helped found Minerva University, where all the classes are synchronous and online. We are able to take advantage of some of the best teachers in the world, who don’t all happen to live in San Francisco. The money we saved by not building a campus translated into a tuition cap that makes a truly world-class education more affordable. But is it preferable to have all universities run that way? Maybe not.

Mark Leviton: Now that I’m fully vaccinated, I’ve been able to see friends in person for the first time in fifteen months, and it’s been an eerie experience in some ways. I wasn’t expecting it to feel so alien — like I have to relearn how to talk to people.

Daniel Levitin: I hear you. My wife and I just went over to my best friend’s house, maybe half a mile from ours in Los Angeles. We hadn’t seen them in a year. We had an outdoor meal. We sat six feet apart. We didn’t hug. At the end of the evening, my wife and I felt it hadn’t been entirely enjoyable. And we love these people.

Have we, as a society, become traumatized in some new way? I don’t know, but I think there’s going to be a long transition period into whatever’s next.