Transcription
Welcome to Huberman Lab Essentials, where we revisit past episodes for the most potent and actionable science-based tools for mental health, physical health, and performance. I'm Andrew Huberman, and I'm a professor of neurobiology and ophthalmology at Stanford School of Medicine.
Today, we're going to talk about an extremely important topic that's central to our daily life: motivation. We're going to discuss pleasure and reward, what underlies our sense of pleasure or reward, and we'll also talk about addictions. Additionally, we'll cover the neurochemistry of drive and mindset.
But for now, let's focus on the neuroscience of motivation, reward, pleasure, and pain, because those are central to what we think of as emotions. Whether or not we feel good, whether we feel we're on track in life, or whether we feel we're falling behind, motivation is fundamental to our daily life. It's what allows us to get out of bed in the morning and pursue long-term or short-term goals.
Motivation and the chemistry of motivation are tightly wound with the neurochemistry of movement. In fact, the same single molecule, dopamine, is responsible for our sense of motivation and for movement. It's a fascinating molecule that lies at the center of many great things in life, as well as many terrible aspects, namely addiction and certain forms of mental disease.
So, if ever there was a double-edged blade in the world of neuroscience, it's dopamine. There's a fundamental relationship between dopamine released in your brain and your desire to exert effort. You can actually control the schedule of dopamine release, but it requires the appropriate knowledge. This is one of those cases where understanding how the dopamine system works will allow you to leverage it to your benefit.
Let's get a few basic facts on the table. Dopamine was discovered in the late 1950s as the precursor, meaning the thing from which epinephrine or adrenaline is made. Epinephrine is the same as adrenaline, but in the brain, we call it epinephrine. It allows us to get into action, stimulating changes in the blood vessels, heart, and organs that bias us for movement.
Dopamine was initially thought to be just the building block for epinephrine; however, it does a lot of things on its own. It's not always converted to epinephrine. Dopamine is released from several sites in the brain and body, but perhaps the most important one for today's discussion about motivation and reward is something sometimes called the reward pathway. For aficionados, it's sometimes called the mesolimbic reward pathway, but it's fundamentally important to your desire to engage in action and for people getting addicted to substances or behaviors.
So, how does this work? You've got a structure in the deep part of your brain called the VTA, or ventral tegmental area. The VTA contains neurons that send what we call axons—little wires that spit out dopamine—at a different structure called the nucleus accumbens. These two structures, the VTA and nucleus accumbens, form the core machinery of the reward pathway and the pathway that controls your motivation for anything.
You can think of them like an accelerator; they bias you for action. However, within the reward pathway, there's also a brake. The brake, or restriction on that dopamine, which controls when it's released and how much is released, is the prefrontal cortex. The prefrontal cortex is the neural real estate right behind your forehead. You hear about it for decision-making, executive function, planning, etc. Indeed, it's responsible for a lot of those functions.
It's this unique real estate that we were all endowed with as humans. Other animals don't have much of it; we have a lot of it. The prefrontal cortex acts as a brake on the dopamine system. This brings us to the important feature of motivation: it is a two-part process about balancing pleasure and pain.
When you're just sitting around not doing much, this reward pathway is releasing dopamine at a rate of about three or four times per second. It's firing at a low level. If suddenly you get excited about something—anticipate something—not receive a reward, but get excited in an anticipatory way, then the rate of firing in this reward pathway suddenly increases to like 30 or 40 times. This creates a sense of action or desire to move in the direction of the thing that you're craving.
In fact, it's fair to say that dopamine is responsible for wanting and craving. This is distinctly different from the way it's normally talked about, which is that it's involved in pleasure. Yes, dopamine is released in response to sex, food, and many things, but it's mostly released in anticipation and craving for a particular thing. It narrows our focus on what we crave, whether it's a cup of coffee, a big board meeting, a final exam, or a person we're excited to meet.
Dopamine doesn't care about what you're craving; it just releases at a particular rate. If we step back and look at the scientific data on how much dopamine firing increases in response to different things, we get an interesting window into how your brain works and why you might be motivated or not motivated.
Let's say you're hungry, looking forward to a cup of coffee, or going to see your partner. Your dopamine neurons are firing at a low rate until you start thinking about the thing you want. When you eat that food, the amount of dopamine released in this reward pathway goes up about 50% above baseline.
Sex, which is fundamental to our species' continuation and reproduction, releases dopamine and increases dopamine levels about 100%. Nicotine increases the amount of dopamine about 150% above baseline. Cocaine and amphetamine increase the amount of dopamine released a thousandfold within about 10 seconds of consuming the drug.
However, just thinking about food, sex, nicotine, or cocaine can increase the amount of dopamine released to the same degree as actually consuming the drug. It depends; for instance, the cocaine user, the addict who wants cocaine, can't just think about it and increase the amount released a thousandfold. It's much lower, but it's just enough to put them on the motivation track to crave that particular thing.
There are reasons why you would have brain circuitry like this. Brain circuitry like this didn't evolve to get you addicted; it evolved to motivate behaviors toward particular goals: water when you're thirsty, sex to reproduce. These brain areas and neurons were part of the evolutionary history that led to the continuation of our species.
Things like cocaine and amphetamine are disastrous for most people because they release so much dopamine and create closed loops where people only crave those substances. Most things don't release that level of dopamine. Nowadays, there's a ton of interest in social media and video games. There have been measurements of the amount of dopamine released during video games, especially those with a very high update speed where there's novelty all the time. Novelty is a big stimulus for dopamine, and those can release dopamine somewhere between nicotine and cocaine—very high levels of dopamine release.
Social media is interesting because the amount of dopamine released in response to logging on could be quite high, but it seems likely that there's a taper in the amount of dopamine. Yet, people still get addicted. So why is it that we can get addicted to things that fail to elicit the same massive amount of pleasure that they initially did?
Being addicted to something isn't just about the fact that it feels so good that you want to do it over and over again. That's because of this pleasure-pain balance that underlies motivation. Let's look a little closer at the pleasure-pain balance because therein lies the tools for you to control motivation toward healthy things and avoid motivated behaviors toward destructive things.
There are many reasons why people try novel behaviors, whether those are drugs, adventure thrill-seeking, or taking a new class. I'm not placing any judgment or value on these behaviors, although I think it's fair to point out that for most people, addictive drugs like cocaine and amphetamine are very destructive.
We know that about 15 to 20% of people have a genetic bias toward addiction. You sometimes hear that the first time you use a drug, you can become addicted to it. That's not been shown to be true for most things and most people, but for some, it actually is true.
In any case, the way addiction works and the way motivation works generally in the non-addictive setting is that when you anticipate something, a little bit of dopamine is released. Then, when you engage with that thing, the amount of dopamine goes up even further. However, as you repeatedly pursue a behavior and engage with a particular thing—let's say you love running or chocolate—when you eat a piece of chocolate, it tastes good.
Then, there's a shift away from activation of dopamine, and other chemicals are released that trigger a low-level sense of pain. You might not feel it as physical pain, but the craving you feel is both one part dopamine and one part the mirror image of dopamine, which is the pain or craving for yet another piece of chocolate.
This is a very important and subtle feature of the dopamine system that's not often discussed. People always talk about pleasure: you love social media, so it gives you dopamine, and you engage in that. You like chocolate; it releases dopamine, so you do that. But for every bit of dopamine released, there's another circuit in the brain that creates a downward deflection in pleasure, which we're calling pain.
So, you engage in something you really want, and there's an increase in pleasure. Then, without you doing anything, there's a mirror image of that, which is a downward deflection in pleasure, which we call pain. For every bit of pleasure, there is a mirror image experience of pain, and they overlap in time very closely.
It's sometimes hard to sense this, but try it the next time you eat something really delicious. You'll take a bite; it tastes delicious, and part of the experience is to want more of that thing. This is true for any pleasurable experience.
Now, the diabolical part about dopamine is that because it didn't evolve to get you to indulge in more and more of something, what happens is that initially, you experience an increase in pleasure, and you also experience this increase in pain shortly after or woven in with the pleasure that makes you want more of that thing.
With each subsequent time you encounter that thing, the experience of dopamine release and pleasure is diminished a little bit, and the pain response is increased a little bit. This is best observed in the context of drug-seeking behavior. The first time someone decides to take cocaine or amphetamine, they will experience a huge dopamine release and likely feel very good.
However, the next time they take it, it won't feel quite as good, and it won't feel as good the third time or the next time. But the amount of pain, the craving they experience for the drug, will increase over time. So much of our pursuit of pleasure is simply to reduce the pain of craving.
The next time you experience something you really like, I don't want to take you out of that experience, but it's important to notice that if there's something you really enjoy, part of that enjoyment is about the anticipation and wanting more of that thing. That's the pain system in action.
We can distinguish between dopamine, which is really about pleasure, and dopamine, which is about motivation to pursue more in order to relieve or exclude future pain. Let me repeat that: dopamine isn't as much about pleasure as it is about motivation and desire to pursue more in order to reduce the amount of pain.
Now, we're talking about psychological pain and craving. People who miss a lover very badly or crave food or are addicted to a drug and can't access it will experience that as a physical craving and a mental craving. The body and brain are linked in this way; they'll describe it as painful. They yearn for it, and I think the word "yearning" is very valuable in this context because yearning seems to include a whole-body experience more than just wanting, which could just be in the mind.
Your desire for something is proportional to how pleasurable it is to indulge in that thing, but also how much pain you experience when you don't have it. You can now start to let your mind wander into all sorts of examples of addictions or things that you happen to like.
I'll use the example that I sometimes use, which is my love of croissants. The taste of that croissant makes me want to eat more croissant. Eventually, blood sugar goes up, satiety is reached, etc. What happens then? What is satisfaction and satiety about?
Well, that's a separate neuromodulator; it's about serotonin, oxytocin, and a hormone system that involves something called prolactin. We'll talk about all of those in the book "The Molecule of More," a wonderful book. Those were described as the "Here and Now" molecules, the ones that allow you to experience your sensations and pleasure in the present and for which the brain stops projecting into the future.
Now, let's talk about craving and these so-called "Here and Now" molecules and how those engage in a kind of push-pull balance that will allow you to not just feel more motivated but also to enjoy the things in life that you are pursuing to a much greater degree.
We have neurons in an area of our brain called the raphe. The raphe releases serotonin at different places in the brain. Serotonin is the molecule of bliss and contentment for what you already have. I've talked before about exteroception, which is a focus on the outside world—everything beyond the confines of your skin.
I've also talked about interoception, a focus on things happening internally within the confines of your skin. Dopamine and serotonin can be thought of as related to exteroception. Dopamine makes us focused on things outside us that are beyond what we call our personal space, where we actually have to move and take action to achieve things.
Serotonin, in general, has to do with the things that are in our immediate "Here and Now," hence the description of these as the "Here and Now" molecules. It's interesting to point out that the body and brain can direct their attention toward things outside us or inside us or split our attention between those.
Just understand that dopamine biases us toward thinking about what we don't have, whereas serotonin and some related molecules, like the endocannabinoids, make you feel blissed out and content in the present.
So, you've got these two systems that are kind of like a push-pull. If you were to say, in the book "Wherever You Go, There You Are," Jon Kabat-Zinn talks about a meditation practice that's different from most. This practice is where you eat one almond and focus all your attention on the taste and texture of the almond.
That's really a mindfulness practice geared toward trying to take a behavior that is normally about pursuit—feeding, which we engage in because of dopamine—and bring it into the "Here and Now." This is a mental trick or task that the mindfulness community has embraced to create increased pleasure for what you already have.
It's really trying to accomplish a shift from dopamine being released to serotonin and the cannabinoid system being involved in that behavior. Dopamine has the quality of making people rabidly pursue things. Drugs like marijuana and opioids, which hit the serotonin system hard, tend to make people lethargic and content to stay exactly where they are.
They don't want to pursue much at all. So, you've got these molecules like dopamine that make you focused on the things you want and crave, and then you've got the molecules that make you content with what you have.
The most important thing, perhaps, in creating a healthy emotional landscape is to have a balance between these two neuromodulator systems. At about this point in the podcast, I'm guessing some of you are thinking, "Okay, great! I want more dopamine. I want to be more motivated. I don't want to procrastinate as much, and I want to experience life."
I want these "Here and Now" molecules to be released as well. There is a way to do that, but you have to understand that the source of procrastination is not one thing. There are basically two kinds of procrastinators, according to research.
The first kind are people who really enjoy the stress of the impending deadline; it's the only way they can get into action. The other kind are those who simply are not releasing enough dopamine. For those people, there are a variety of things that can increase dopamine.
I suggest you talk to a psychiatrist or doctor. I've talked about mucuna pruriens, which is 99.9% L-Dopa, the precursor to dopamine. There are antidepressants like Wellbutrin (Bupropion) that increase dopamine and epinephrine.
However, if you think back to our earlier discussion about dopamine, if it's very high, it creates a sense of pleasure and the desire for more. You can also become a person for whom enough is never enough. The only thing that dopamine really wants is more of the thing that releases dopamine.
One of the things you can do to be a happier person, especially if you're pursuing long-term goals, is to extend the positive phase of dopamine release and blunt the pain response. You can do this cognitively.
I used to joke with my lab that when we'd publish a paper, I would get really excited, but I wouldn't allow myself to get too excited. What I wanted to do instead was extend the arc of that positive experience as long as I could by thinking back, "Oh, that was really cool! I really enjoyed doing that work. I really enjoyed the discovery."
You can extend pleasure without having to engage in the behavior over and over. That's extending the arc of that dopamine release as well; it offsets some of the pain of not having that experience occur repeatedly.
Now, for the high performers out there, you're probably familiar with this. Many people who achieve big accomplishments often think, "Well, now what? What am I going to do next? How am I ever going to exceed that?"
Indeed, many people who are very high on the dopamine sensation and novelty-seeking scale are prone to addiction. They're prone to the rabid pursuit of external goals, neglecting the internal mechanisms that allow them to feel calm and happy.
For people who are very driven and motivated, adopting a practice of engaging in the "Here and Now," like the almond practice we talked about earlier, along with learning how to achieve a good night's sleep regularly through tools and mechanisms discussed in previous podcasts, gives us balance between pleasure-seeking and offsetting pain.
Pleasure is really two things: the joy in pursuit and the joy in what you have. The cool thing is you can regulate this whole system in a way that will steer you toward more positive anticipation of things in life and less disappointment.
It's simply a matter of adjusting what we call the dopamine schedule. To understand how to control the dopamine system and leverage it for a better life, you need to understand the results of a very important experiment.
This experiment was able to separate pleasure from motivation. It's a simple but elegant experiment. They offered rats food they particularly liked, and the animals would lever press for a pellet of food—kind of a classic experiment. They'd eat the food and presumably like it because they were motivated to press the lever and eat it.
Great. They took other rats and eliminated the dopamine neurons. You can do this by injecting a neurotoxin that destroys these neurons, so they had no dopamine in their brain and no ability to release dopamine. They gave them a lever, and the rats would sit there, hit the lever, and eat the food. They still enjoyed the food.
So, you might say, "Okay, so dopamine isn't involved in motivation or pleasure." No, it absolutely is. They could still enjoy the food, but if they moved the rat literally one body length away from the lever, what they found was that the animals with dopamine would move over to the lever, press it, and eat.
The rats without dopamine wouldn't even move one body length to press the lever and get the food. Therefore, dopamine is not about the ability to experience pleasure; it is about motivation for pleasure.
Many of you are probably thinking, "Wow, I'm not a very motivated person." Like we talked about with one kind of procrastination earlier, what about when I just feel kind of "meh" about life?
For some of you, there may be real clinical depression, and you should talk to a professional. There are very good prescription drugs that can really help people. There are also great non-drug treatments, such as psychotherapy and other treatments being developed.
I think the data point to the fact that a combination of pharmacology and talk therapies is generally best, and there are a huge range of these options. I know many of you are in these professions, so we're not going to talk about that right now.
There is a compound that's interesting in the supplement space. It's not mucuna pruriens or L-tyrosine, which promote massive releases of dopamine. It's a combination of dopamine and serotonin, and it's an intriguing molecule.
It's sold over the counter, but you have to check with your healthcare provider before taking anything. It's phenylethylamine, or PEA. PEA releases dopamine at low levels but also serotonin at low levels, so it's kind of a cocktail of the motivation molecules and the "Here and Now" molecules.
People's responses to this vary widely, but many report feeling heightened mental acuity and well-being. It is a bit of a stimulant, like anything that triggers activation of the dopamine and norepinephrine pathways, but it's an interesting supplement.
Now, let's talk about what a dopamine schedule is and how you can leverage this to have heightened levels of motivation without experiencing a crash afterward. You can also experience heightened pleasure from the various pursuits in life.
Here's the key principle: dopamine is very subjective. You can either allow yourself to experience the pleasure of reaching a milestone or achieving some craving, or not. It's actually pretty powerful what one can do with the subjective system.
In fact, I'm going to describe an experiment that highlights just how powerful the subjective readout or interpretation of a given experience can be, even at the level of pharmacology. The title of the experiment is "Expectation for Stimulant Type Modifies Caffeine's Effects on Mood and Cognition."
This was done with college students. It's a fascinating study. They gave college students either a placebo (essentially nothing) or 200 milligrams of caffeine. That's about what's in a typical medium coffee. They took 65 undergraduate students, randomized them to either placebo or caffeine, and told them they were either getting caffeine or Adderall.
Adderall cognitively carries a very different expectation. College students know Adderall to be a much stronger stimulant than caffeine. They know it creates a sort of high. This is how the students described it, and they thought it would increase their level of focus and ability to perform work.
What's really interesting is there was definitely an effect of placebo versus caffeine; that's not surprising. You take a placebo, and you may or may not feel more alert. But you take 200 milligrams of caffeine, and you're likely going to feel very alert.
However, there was also an effect of whether the students thought they were getting caffeine or Adderall. The subjects receiving caffeine reported feeling more stimulated, anxious, and motivated than those who received the placebo.
But the ones who expected Adderall reported stronger amphetamine effects. They performed better on a working memory test and generally had all the increased cognitive effects that would have been seen with Adderall, but they were only ingesting caffeine.
This highlights the fact that higher-level cognitive processes impact even the most basic fundamental aspects of dopamine release or adrenaline release in ways that can positively impact performance. In this case, it was a positive improvement in working memory and focus.
So today, we've talked a lot about the dopamine system and the kinds of schedules that will allow craving or addiction. But what's the schedule of dopamine that will allow you to maximize your pursuit of pleasure and eliminate pain?
We get the answer to that from our good friend gambling. The reason gambling works, why people throw their lives away, and why they go back again and again to places like Las Vegas and Atlantic City is because of hope and anticipation. Those are cities built on dopamine; they leverage your dopamine system.
As a friend of mine, a certified addiction treatment specialist, tells me, gambling addiction is particularly sinister because the next time really could be the thing that changes everything. Unlike other addictions, the next time really could change everything, and that's embedded in the mind of the gambling addict.
Rarely does it work out in favor of the well-being of the gambling addict and their family. However, the intermittent reinforcement schedule was discovered long ago by scientific researchers. This is the slot machine that every once in a while gives you a win to keep you playing.
This is the probability of winning at the craps table, roulette table, or blackjack—just often enough that you're willing to buy tickets, head out there, and play again. You might even go downstairs from your room, even though you swore you were done for the night.
Intermittent reinforcement is the most powerful form of dopamine reward schedule to keep you doing something. We can export that; we can use it for good. If there's something you're pursuing in life—whether it's an academic goal, financial goal, or relationship goal—one of the things you can do to ensure you remain on the path to that goal for a long time and continue to exceed your previous performance is to occasionally remove reward subjectively.
Let's say you set out a goal of making a certain amount of money. This could also apply to sports, school, music, or any creative endeavor. As you reach each of those goals, you should know that the amount of dopamine is not going to peak; it's actually going to diminish and make you crave more.
The key to avoiding that crash, while still keeping it in healthy levels that allow you to continue your pursuit, is that as you stair-step toward your goal, you actually want to blunt the reward response for some of those intermediate goals.
Now, I'm not telling you not to celebrate your wins, but I'm telling you not to celebrate all of them. A good friend of mine, who recently had great financial success, asked me and another good friend—who understands dopamine reward schedules at a deep level—what to do next.
We said, "Oh, well, that's simple. You should just give most of it away." This wasn't a ploy to receive any of the money ourselves; it was really about reducing the impact of that reward.
Hopefully, giving money away, if you already have enough, would be rewarding in and of itself. But if you're a student pursuing goals at university or an athlete pursuing goals, it makes sense from a rational perspective, once you understand these mechanisms, to hit a new high point of performance or get that A+ (or A-), and then tell yourself, "Okay, that was good," but actively blunt the reward.
Don't go and celebrate too intensely because in doing that, you keep your dopamine system in check and ensure that you stay on the path of continued pursuit—not just for that thing, but for all things.
Big increases in dopamine lead to big crashes in dopamine. Big increases in dopamine up the ante. You can lift what Las Vegas, Atlantic City, and other gambling mechanisms have known for a long time. They lifted it from scientists; you can now take it back.
You can start to leverage that by making it intermittent. Reward yourself not on a predictable schedule—so not every other time, every third time, or every tenth time—but sometimes it's three in a row, then not at all for ten days.
Reward is important; self-reward is critically important. But make sure you're not doing it on such a predictable schedule that you burn out these dopamine circuits or undercut your ability to strive and achieve.
Hopefully, you now know far more about the dopamine system, reward, and motivation than you did at the beginning of this podcast. Hopefully, you also understand the other side of dopamine and reward, which is pain, and the balance of this pleasure-pain system, as well as the molecules described in "The Molecule of More" book, like serotonin and the endocannabinoids.
Finally, I want to thank you for your time and attention today. I hope you learned a lot and that you discovered possible tools you could incorporate into your life as it relates to motivation and emotions. Thank you for your interest in science.