Welcome to the Huberman Lab Podcast, where we discuss science and science-based tools for everyday life. My name is Andrew Huberman, and I’m a professor of neurobiology and ophthalmology at Stanford School of Medicine. This podcast is separate from my teaching and research roles at Stanford, but is part of my desire and effort to bring zero-cost to consumer information about science and science-related tools to the general public.

In keeping with that theme, I’d like to thank the sponsors of today’s podcast. Our first sponsor is InsideTracker, a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and inform your health goals. I’m a big believer in getting blood tests taken, because it’s the only way to get in-depth data about your metabolic factors, hormones, and other things that inform your immediate and long-term health. Nowadays, there are also excellent DNA tests that can further inform you about your health.

The problem with most blood tests out there is that you get information back, with a lot of numbers, and they’ll tell you whether or not your numbers are in normal range or high or low, but they don’t inform you what steps to take as a consequence.

InsideTracker has a dashboard and platform that makes interpreting all the factors and what they mean easy. It also points you in the direction of certain lifestyle factors, such as exercise and nutrition, that you might want to change in order to bring the numbers into the ranges that you want. I have been using InsideTracker for some time now, and it has really helped me inform the choices I make. For instance, I have swapped out some of the foods that I was eating regularly, as I found out I was too high in certain vitamins and minerals, and too low in others. It has really helped me adjust my diet and exercise regimes, and it gives me the confidence that I’m on the path to long-term health.

If you want to try InsideTracker, you can go to insidetracker.com/huberman to get 25% off any of InsideTracker’s plans. Use the code Huberman at checkout.

ExpressVPN is a virtual private network (VPN) that keeps your data safe and secure by routing your internet activity through their servers and encrypting it. This prevents anyone from seeing or selling your data. I started using ExpressVPN after my bank account got hacked. I still don’t know how it happened, but it was a huge mess. I lost money and a lot of time, and I wouldn’t want anyone else to go through it.

After the incident, I spoke to my friends in the tech community and they told me that even though I thought my internet connection was secure, it wasn’t always the case. I use internet connections in planes, hotels, cafes, and even at home, and I was told that even at home, my data may not be as secure as I thought. That’s why I decided to use ExpressVPN.

ExpressVPN ensures your data and online activities are secure. It runs in the background without interfering with your online activities. I use it when I travel, at work and at home. If you want to try ExpressVPN, you can go to expressvpn.com/huberman and get an extra three months free on one of their one-year packages. The final sponsor of today’s podcast is Magic Spoon, a zero-sugar, grain-free, keto-friendly cereal. I’m not ketogenic, all-meat, nor vegan, but I still enjoy Magic Spoon.

I have a fasting and low carbohydrate diet during the daytime to optimize alertness and wakefulness. For my evening meal, I eat carbohydrates to facilitate the transition to sleep. Magic Spoon cereal is a great snack for me in the afternoon as it is keto-friendly and comes in a variety of delicious flavors, such as cocoa, fruity, peanut butter, and frosted. I particularly like the frosted because it tastes like donuts, and I love donuts. As a result, I love Magic Spoon cereal and can consume it with ease.

The other announcement I’d like to make is about Magic Spoon Cereal.

Magic Spoon is a low-carb, keto-friendly, gluten-free cereal that tastes like a pastry. It has zero grams of sugar, and it’s compatible with the nutritional regimen I mentioned earlier. If you want to try Magic Spoon, you can go to magicspoon.com/huberman and use the code Huberman at checkout to get $5 off your order.

This month, we’re talking all about the science of emotions and the tools related to it. We’ve discussed the science of stress and resiliency, and the tools to access more calm, as well as tools to raise your stress threshold and become more resilient. We’ve also talked about motivation and the role of the dopamine system.

I’d like to make a couple of announcements about some new resources. Firstly, all the Huberman Lab episodes have now been captioned in English and Spanish. This was made possible thanks to the support of our sponsors and Patreon. Secondly, I’d like to mention Magic Spoon Cereal.

So now, all of the podcasts have a captioning feature on YouTube, and those were done by experts. So while there might be the occasional error, for the most part, they’re very precise. We’ve done that so that people that prefer to consume the content in Spanish or that like to read the content from the English subtitles can do so. And we’re going to continue to expand the number of languages that are captioned for the Huberman Lab Podcast. So we want to thank you for that resource. It’s now available for all episodes.

In addition, in previous episodes I’ve talked about NSDR or non-sleep depressed. NSDRs come in in a variety of different forms, there’s self-hypnosis. I’ve pointed you to some resources for that previously. There’s yoga nidra.

Non-Sleep Deep Rest (NSDR) is a self-directed way to achieve calm quickly. It can help access sleep more readily, de-stress deeply, and replace lost sleep. It has also been linked to aiding neuroplasticity, which is the rearrangement of connections in the brain that occur during learning. To access a free NSDR script, there is a link in the episode caption to a YouTube video brought to you by Madefor, a podcast sponsor. This script does not contain the typical language of yoga nidra, but instead focuses on breathing protocols and a body scan. It is about 30 minutes long and should be effective in bringing deep states of relaxation for the reasons previously mentioned.

Emotions are a fascinating and vital aspect of our life experience. They make up most of what we think of as our experience of life, even the things we do, our behaviors and the places we go, and the people we end up encountering in our life, all of that really funnels into our emotional perception of what those things mean, whether or not they made us happy or sad or depressed or lonely, or were all inspiring.

One thing that is absolutely true is that everyone’s perception of emotion is slightly different. Meaning, your idea of happy is very likely different than my idea of what a state of happiness is. This is also true for color vision. Even though the cells in your eye and my eye that perceive the color red are identical right down to the genes that they express, we can be certain based on experimental evidence and what are called psychophysical studies, that your idea of the most intense red is going to be very different than my idea of the most intense red if we were given a selection of 10 different reds and asked which one is most intense, which one looks most red.

Emotions are complicated and yet they are tractable. They can be understood. Today we’re going to talk about a lot of tools to understand what emotions are for you to understand what your emotional states mean and what they don’t mean. In doing that, that will allow you to place value on whether or not you should hold an emotional state as true or not true, whether or not it has meaning or it doesn’t, as well as whether or not the emotions of others are important to you in a given context. We’re also going to talk a lot about development.

Today we’re going to center a lot of our discussion around infancy and puberty. We’re also going to talk about tools for enhancing one’s emotional range and for navigating difficult emotional situations. I have some background in psychology, but I’m not a clinical psychologist or therapist. Instead, I’m going to be drawing from the psychology greats who studied emotion and emotional development, and linking that to the neuroscience of emotion. We now understand a lot about the chemicals, hormones, and neural circuits in the brain and body that underlie emotion. While there’s no one single universally true theory of emotion, at the intersection of many of the existing theories, there are really some ground truths. Today we’re going to visit those ground truths, talk about the tools that emerge from them, and discuss some wild and wacky experiments people are doing such as inhaling different types of hormones to get attached more quickly. We may even do some experiential stuff today if you like.

And then, you have to look at the neurotransmitters that are present in that brain area.

Today we’re going to explore how emotions develop in the brain. We’ll look at where emotions first develop and the rule of neuroanatomy that helps us understand what a part of the brain does. To do this, we must address two questions: what connections does the brain area make and what neurotransmitters are present in that area. By exploring these aspects of the brain, we can gain a better understanding of emotions.

In order to understand the role of an area of the brain, it is important to know where it gets inputs from and where it sends inputs. For example, if an area of the brain gets direct input from the neurons in the nose, it is likely that it has a role in analyzing smell or measuring something about odors. Additionally, if it gets input from the eye, it is likely that it also gets input from the visual system and cares about light and photons. It is also important to know the developmental origin of that structure, as things move around a lot as the brain develops. The brain is a squishy thing floating around in some liquid, which means that things are not always in the same place in two different species or two individuals of the same species. As such, it is important to know where they started out, as this informs what they do as well.

Emotions cannot be pinpointed to one area of the brain. The limbic system has been linked to emotions in various ways and will be discussed today. However, the limbic system is just one component of the brain’s inputs that create emotions. It is not the place for emotions. Lesioning one location in the brain would not eliminate emotions entirely.

Therefore, the question arises: what are the circuits and brain areas for emotion? This is a topic of debate in the present day.

For years, it was thought that there might be circuits in the brain that generate the feeling of being happy, sad, and so on. However, Lisa Feldman Barrett has challenged this idea and has provided evidence to suggest that such circuits probably do not exist. Nonetheless, there is good evidence for circuits in the brain, such as limbic circuits and other circuits, that can shift our overall states or alertness levels, or bias us towards viewing the outside world or paying more attention to what is going on inside our bodies.

Emotions do arise in the brain and body due to the specific connections between specific areas. To understand how emotions work, we must look at how they are built, which happens during infancy, adolescence, and puberty, and continues into adulthood. The groundwork is laid down during early development when we are small children.

A baby comes into the world without any understanding of the things around them. There are two ways that a person can interact with the world: interoception (paying attention to what is going on inside) and exteroception (paying attention to what is going on outside). This is true for the entire life and sets the foundation for understanding emotions. As an infant, the baby does not have any knowledge of what they need and does not understand hunger, toys, cold, or heat.

When you needed something as a baby, you would experience this as anxiety. You would feel an increase in alertness if you had to use the bathroom, were hungry, or were cold. You would vocalize, cry out, or act agitated to cue your caregiver. Your caregiver would then respond to your needs, such as giving you food or changing your diaper. This is important to understand, as babies cannot make cognitive sense of the outside world. Instead, their internal states drive requests, and people come and respond to those requests. If neglected, development does not go well.

Extreme cases of deprivation can be compared to experiments done in the laboratory with animals. For example, mice are given toys, different foods, and other mice to live with. This leads to an increase in brain thickness and neuron branching. However, instead of focusing on deprivation, today we will focus on what healthy emotional development looks like, and what interventions can be used to rescue it. Emotions are about forming bonds and being able to predict things in the world. This is true for babies, who, although we cannot know how they feel, are presumably getting care when they need it. This is also true for adults, who often don’t even know how they feel, let alone how other people feel.

If I were to ask you how you feel right now, it is likely that you would not be able to tell me in a way that I could truly understand. For example, if you said you were very depressed or very happy, I would have some sense of how you feel due to the extremity of the emotions. However, I would not really know how you feel. Similarly, you would have no idea how I feel right now, as I could be feeling any number of emotions.

Expressions, such as pupil dilation, can provide cues of how people feel. However, these cues are not always reliable. To address this issue, a tool called Mood Meter has been developed by researchers at Yale. It is either free or 0.99 and provides a more accurate way of understanding emotions.

But what they’re trying to do is put more nuance and subtlety on our words and language for emotions, and be able to allow you to predict how you’re going to feel in the future. It’s actually quite interesting.

I’m on the app right now called Mood Meter, which can be found on Apple or Android. It asks me, “Hi, Andrew, how are you right now?” I can pick high energy and unpleasant, high energy and pleasant, low energy unpleasant, or low energy pleasant. Right now, I’m feeling high energy pleasant.

After clicking on that, it gives me a gallery of colors and I just move my finger to the location where I think it matches most.

I’m feeling cheerful right now. I’m going to call this work, even though it feels like play. This activity is collecting data on me and linking it to other features I have allowed access to. This helps me to predict how I’m going to feel at different times of the day.

We don’t always have enough language to describe all the emotional states, but there are core truths to what makes up an emotion. To help people better understand what they’re feeling and why, and when best to engage in or avoid certain activities, we can use the continuum of autonomic arousal. This ranges from alert to calm, with 10 being a panic and 1 or 2 being very drowsy. By asking ourselves where we are on the arousal scale, we can gain insight into our emotional states.

Valence is a measure of how good or bad we feel. On a scale of one to ten, I’m feeling a seven. I had a good night’s sleep, a good walk with Costello this morning, and I’m fed and hydrated, so I’m feeling good. There’s also a third measure to consider, which is how much our attention is focused internally on our feelings, and how much it’s focused externally.

Alert versus asleep, good versus bad, and focused internally or externally – these three features make up much of what we call emotions. When looking at theories of emotion, many different components can be seen, but they all seem to center back to these three features in some way or another. When we are really stressed, this can put us in a position to be more in touch with our body and have more bodily sensations. This is known as being interoceptive. On the other hand, if we are triggered by something like a text message or comment, this is known as being exteroceptive. This balance is always dynamic, and understanding these features can help us to better understand emotions.

It can be very powerful to understand and look at our emotions through the lens of an infant. The infant in the crib is mostly interocepting. As caregivers provide what it needs – milk, diaper changes, a warm blanket if it’s cold, or pulling off the blanket when the baby’s fussing and it’s too warm – the baby starts to exterocept. It begins to look into the outside world and make predictions, such as “If I cry a little bit then mom comes over and I get my milk”. Babies are not doing this consciously, but rather strategically in order to relieve anxiety.

We start to learn that when we feel something, we can look towards the outside world to try and make ourselves feel better. This can be as simple as looking for a snack when we feel hungry, or texting a friend when we feel anxious. It’s a reflexive action that we start to learn from infancy and continue to do throughout adulthood. We balance both interoceptive and exteroceptive focus, looking inward to understand our feelings and looking outward to understand how to meet our needs.

Remember, emotions are really there to form bonds and to make predictions. Sometimes sadly there is neglect, and people don’t show up for us the way that we would like. Our responses to that have to do with whether or not we predict whether or not they would or not. When we expect something and it doesn’t happen, it’s a big let down.

The many theories of emotion include the triune brain theory, which proposes that you have a primitive and involved brain, though this is on shaky ground these days. Darwin proposed that there are universal expressions of emotions. Helen Fisher’s work on love suggests that there are circuits in the brain for love and long-term bonds. Lisa Feldman Barrett’s work suggests that emotions are contextual and have a social component.

Allan Schore, a clinical psychologist and researcher at UCLA, has studied the role of right brain and left brain in emotional development. He suggests that to understand our emotional experience, we need to pay attention to both our inward and outward states. As infants and young toddlers, we focus mainly inward and use what we observe outward to predict what will bring us relief and remove our anxiety. To further our understanding of emotion, Schore suggests two tools: the Mood Meter app, which can help us understand the nuances of emotions, and the three axes of emotion, which include alertness and calmness, how good or bad we feel, and whether we are focused inward or outward. Finally, Schore references classic experiments by Bowlby and Ainsworth that inform us about the kind of baby we were and how that affects our emotionality now.

Anyone who has studied psychology or taken a psychology class might have learned about the classic experiment known as the Strange Situation Task. In this experiment, a mother and child come into the laboratory and play together for a while. The mother then leaves for a period of time, and the research focuses on the child’s response when the caretaker returns. Most children will cry when their primary caretaker leaves, as they have formed a bond and an attachment. This experiment has also been done with fathers.

The a babies responded with happiness when their caretaker returned. They would get upset when their caretaker left, but when they returned they would show delight and go to them. The b babies responded differently. They would not show any emotion when the caretaker left, and when they returned they would not respond with happiness, but rather stay distant and aloof. The c babies would be quite distressed when their caretaker left, but when they returned, they would not show any emotion. Finally, the d babies would not show any emotion when the caretaker left or returned. They were referred to as the “unaffected” babies.

Secure attached kids feel relieved when their caretaker returns after a period of separation. They have a healthy response to both separation and re-engagement with their caretaker. In contrast, babies referred to as ‘avoidant’ were less likely to seek comfort from their caregiver upon their return. Instead, they would often stay with an adult in the room or continue to play with their toys. It is unclear whether these avoidant babies become avoidant adults. The third type of baby, referred to as ‘c babies’, respond to the return of the caregiver with acts of annoyance. They seem angry. Don’t run away with any conclusions about this just yet.

So, the research showed that infants had four distinct reactions to their returning caregiver. The first were the “A babies” who were happy to be reunited with their caregiver. The second were the “B babies” who showed ambivalence, wanting to bond but also seeming somewhat annoyed. The third were the “C babies” who were disorganized and fearful, and the fourth category, added later, were the “D babies” who avoided interactions with everyone and whose behavior did not change whether the caregiver was present or not. The experiments have been repeated in a variety of different contexts.

Mary Main conducted research at UC Berkeley and other institutions looking into variations of the same theme. Over time, it became clear that some babies feel secure when they reconnect with their caregiver, while others are confused or don’t. This classic work opened up a set of important questions about what reestablishment of the bond is really about, and what defines a secure attachment, an insecure attachment or an avoidant attachment.

The four main factors that define the bond are gaze, vocalizations, affect or emotion, and touch. Gaze does not need to be direct and without blinking, it can just be looking at each other. Vocalizations refer to what we say and how we say it. Affect or emotion is how we express it, such as crying or smiling. Finally, touch is also a factor.

Gaze, vocalization, affect, and touch are the core components of social bonds and emotionality. We know that there are brain areas like the fusiform face area, deep in the brain, which is responsible for processing faces. Children’s recognition of their parents’ faces and voices is highly accurate, and likewise, parents’ recognition of their child’s vocalizations, not just voices, but cries, is remarkable. If you’ve ever been in a situation where someone with small children can hear something you can’t, it is as if they have wolf hearing. This perception of voices is supported by evidence that we are tuned to the frequencies of voices of people we care about.

It is not just true in rodents and other mammals, but also humans. Babies are very tuned in to the sound of their mother’s voice, even while they are in the womb. This phenomenon is known as mother-ease, which is the particular style of speech that mothers and other caretakers use with children. It involves how people look at each other, what they say, what they seem to be feeling and how that makes the other person feel. Additionally, couples come to know each other exceedingly well, so much so that it can both benefit and injure their relationship. However, people have a range in terms of how tuned into these subtle interactions they are. Some people are more tuned into this than others.

John Bowlby and his colleagues developed a model of attachment that has a lot to do with face processing, gaze, vocalizations, and touch. This raises the question of what it is when we feel something – is it because of something spontaneous in us, or something we’ve seen or heard? Nowadays, people get a lot of information about the people they know through online activities, and this can have an impact on their internal state. It is important to be able to recognize when your internal state is being driven by external events, as this is key to being able to emotionally regulate. People who are constantly being pulled around by external events are said to be emotionally labile and not in control of their emotions. Even if they seem calm, it may only be because they are in a placid environment. If something disturbs the environment, they may not be able to remain calm.

The outside environment can disrupt our internal environment, which is connected to our attachment style as a baby. We cannot travel back in time to know for sure, but we can examine two development periods: adolescence and puberty, and adulthood. There is an exercise we can do to assess whether we have a bias for exteroception or interoception. This will vary with circumstance. For example, when we attend a party, we may worry about our appearance or if we said something wrong. Similarly, when we do public speaking, it is not just about managing our stress, but also about how much we are focused on external events versus internal events. People who are successful athletes or have high-stress jobs often talk about the concept of getting out of their head.

You only have so much attentional resource, and it can be split between two things: being anchored to one thing and being fully focused on what’s going on internally or externally. To be effective in the world, it is useful to have a lot of your attention focused outward, rather than on the tambour of your own voice, which is more or less destructive for the ability to engage socially. Here is an exercise to illustrate the interoceptive and exteroceptive balance and the extent to which you can move between them deliberately. Close your eyes and concentrate on the contact of any portion of your body with the chair or car seat (but don’t do this while driving). Then, move your attention even more deeply into the sensation of what’s going on in your gut.

Are you full? Are you empty? Are you hungry? Are you not? Is your heart beating, at what rate? What’s the cadence of your breathing? To bring your focus and attention to everything at the surface of your skin and inward, I’m going to do a rare thing on the Huberman Lab Podcast: introduce about five to eight seconds of silence. This is an exercise that you can continue afterward if you want to extend how long you do this.

Try to exterocept something in your immediate space. Restrict the thing to something small enough that it occupies 20% of your field of view. Take five seconds of silence to allow you to exterocept. You may find that some degree of interoception is maintained. It is hard to place 100% of your attention on something externally, unless it is really exciting or novel. You can also do this dynamically by tethering your emotional experience to something external.

You can decide to focus internally and externally, deciding to split the focus 50/50 or 70/30. Developing a heightened ability to do this takes work and involves taking your attentional spotlight and narrowing the aperture of your attention to either the self or something externally. There are practices that have been developed to move interoception and exteroception from one being more heavily weighted than the other. The circuits in the brain that underlie intero and exteroception are anchored in areas of the brain that are involved in attention, such as the frontal eye fields. When you third-person yourself and recognize the location of self relative to the rest of your body, these exercises are at the core of the development of emotional bonds.

The four things we mentioned before – gaze, vocalization, touch and affect – happen dynamically. For example, if someone winks at you, you not only pay attention to the wink but also to how it makes you feel. This is followed by a conversation, which is a very dynamic process. It may seem overwhelming to try and interocept an exterocept and shift the balance, but our brains and nervous systems are very adept at doing this. However, some people have difficulty breaking out of a strongly interoceptive mode while others have difficulty breaking out of their exteroceptive mode. We have biases in how interoceptive or exteroceptive we are, which is influenced by three axes – valence (good or bad), alertness (alert or calm) and interoceptive or exteroceptive bias. These biases can differ throughout the day and across a lifetime.

It’s certainly going to differ according to whatever it is that you’re engaged in. But early in development, you start off with an interoceptive bias. You are starting to develop expectations and predictions about how the outside world is going to work and you are trying to figure out the reliability of outside events and people. Where things are reliable and people are reliable, we are able to give up more of our interoception and trust that our internal needs will be met through bonds and actions of others. This starts to veer toward the discussion about neglect and trauma, which we will devote entire episodes and probably an entire month to. It is important to internalize and understand what we are talking about now in order to get the most out of those future conversations.

Paying attention to how much we interocept or exterocept is important, as our emotions and their intensity can grow or shrink depending on how much we are interocepting. For example, if we are feeling extremely sad and there is an outside event that made us sad, chances are there will be a balance, but the extreme grief or sadness will lead us to mostly interoceptive. When we feel extremely happy, something great happens in the world and we will mostly be aware of our internal state. We are always tethered to the outside world to some degree or another, and this was true from infancy to adulthood.

The second most important aspect of our development as it relates to emotionality and trust is the ability to predict whether things in the outside world are reliable or not in terms of meeting our interoceptive needs. This period is called puberty.

Puberty is an absolute biological event with a beginning and a specific definition: the transition into reproductive maturity. It is accompanied by a number of hormonal changes and brain changes, with the brain changes occurring first. Puberty is now occurring earlier than it did in the past, with the transition starting around age 10 for females and age 12 for males. This number will differ depending on a number of different factors.

Puberty is triggered by body fat, with the hormone leptin playing a key role. Animal studies have shown that leptin can promote leanness, and it communicates to the brain that there is enough body fat to allow metabolic processes to occur. This is why people have difficulty losing the last few pounds – leptin levels are very low. This is the basis for the cheat day/refeed concept, where eating a lot for one day a week while dieting hard can signal to the brain that there is enough leptin.

Leptin is made by body fat and signals the brain to trigger puberty. A paper published in the mid ’90s in the Journal Science showed that leptin could be injected into younger females to accelerate the onset of puberty. It is also involved in various growth effects in the body generally, and interestingly, very obese children don’t necessarily undergo puberty earlier. They tend to be larger boned and have higher bone density because leptin is also involved in bone density. It is unclear whether cheat days provided psychological relief or not, but in any case, it is likely that both factors play a role.

The onset of puberty has interesting social effects, often called pheromone effects. Hormones are substances secreted from one area of the body that travel and impact tissues and cells elsewhere. Pheromones are chemicals released by one member of a species that act on and impact other members of that species or even other species. For example, rodents are very good at detecting the urine and scent markings of large carnivores. Whether or not there are pheromonal effects in humans is debated. On Instagram, some pheromone effects reported in humans were discussed. Some people argued that it has never been shown in humans that there is a pheromonal vomer, or the vomeronasal organ, or Jacobson’s organ.

Human pheromone effects are controversial. Although I think there is ample evidence for them, such as synchronization of menstrual cycles and people being able to detect the odor of their significant others on t-shirts that were washed several times, much more needs to be done to confirm this. One of the more interesting pheromone effects that impacts puberty, at least in animal models, is the so-called Vandenbergh effect. If you take a pre-pubertal female and introduce a novel male that is not a sibling, she will undergo puberty almost immediately.

Striking research has recently been published in the Cell Press journal Current Biology showing that mandrills, a type of primate, exhibit the Vandenbergh effect. This effect occurs when a novel, sexually competent male is introduced to a pregnant female, which can trigger activation of puberty in the female that would otherwise remain pre-pubertal for longer. Additionally, there is the Bruce effect, where the introduction of a novel male to a pregnant female animal can cause spontaneous miscarriage. However, the presence of the father seems to protect against this effect. Whether or not these effects occur in humans is still controversial.

Puberty is triggered by a number of different factors, including changes in GABA expression in the brain, an inhibitory transmitter. One of the more interesting molecules that triggers puberty in all individuals is something called kisspeptin. Kisspeptin is made by the brain and it stimulates large amounts of gonadotropin-releasing hormone (GnRH) to be released. GnRH then causes the release of another hormone called luteinizing hormone (LH), which travels in the bloodstream and stimulates the ovaries of females to produce estrogen and the testes of males to produce testosterone. Kisspeptin has other effects as well, but those are some of the main ones as they relate to puberty. Whether or not this happens in humans is unclear.

At puberty, the testes in males start churning out tons of testosterone in order to trigger the development of secondary sexual characteristics such as body hair, deepening of voice, etc. In females, estrogen is responsible for breast development, etc. Normally, in an adult, a big increase in gonadotropin releasing hormone and luteinizing hormone would eventually be shut down due to a negative feedback loop. This is similar to a thermostat in a house. However, kisspeptin is able to drive very high levels of these hormones in an ongoing way so that puberty can commence and continue. Kisspeptin has also become a popular hormone among athletes as a performance-enhancing drug.

I’m not suggesting anyone do this, but people are buying and injecting kisspeptin for the specific reason that even past puberty, it can stimulate large increases in things like estrogen, testosterone and other hormones. It also has a number of psychological effects, such as increased libido. These effects are subject to feedback loops, so they don’t work indefinitely.

Kisspeptin was only recently discovered, so it is not often heard of when people talk about performance-enhancing drugs or therapeutic endocrinology. However, it has a number of therapeutic uses, such as helping kids who don’t undergo puberty or adults who are hypogonadal, meaning they don’t make enough hormone. This is how puberty is triggered biologically, by leptin and kisspeptin.

When puberty happens, it changes the young person not just reproductively, but also in terms of the social bonds they form and the predictive behavior they can engage in. Puberty shifts a child from a generalist to a specialist.

Puberty is a period of rapid physical, emotional, and social development. During this time, there are genetic biases that influence aspects such as hair color, eye color, and height. However, puberty is also a time when individuals transition from being good at a variety of tasks to being good at a few and poor at many. This is due to the relationship between puberty and neuroplasticity; the brain’s ability to change in response to experience. Adolescents and children in puberty are also preoccupied with questions about their place in social structures, who they can rely on, and how they can make reliable predictions in the world. Puberty is the fastest period of maturation in an individual’s life.

Puberty is the largest change that you will go through at any point in your life in terms of who you are. This is because your biology has fundamentally changed at the level of your brain and all your bodily organs, from the skin inward. Research has uncovered some of the core needs that occur during puberty and adolescence, which are important for successful emotional maturation. A review article published in the journal Nature, one of the top three premier journals in the field of science, highlights changes in neurons and neural circuits. For instance, there is a connection between the dopamine centers in the brain and an area of the brain that is involved in emotion and dispersal. During this time, both in animals and humans, there is an intense desire to get further away from primary caregivers. This is not permanent, and the action is always in a direction away from the primary caregiver.

Puberty and adolescence is a normal biological process that is seen in many mammalian species. It is characterized by a desire to spend more time with peers and less time with adults. This is often accompanied by changes in the brain, organs, and body shape. Parents of teenagers should be aware that this is a normal process and there are strategies to promote healthy development. These strategies were listed previously and include things such as providing support, promoting physical activity, and encouraging healthy eating habits.

This article is very interesting because it was written by Ronald Dahl, from the School of Public Health at University of California, Berkeley, Nicholas Allen, Linda Wilbert and Anna Balanoff Suliman. I know Dr. Wilbert quite well, as she has done the work on dispersal and is quite well known for that work. It is an extensive review, but accessible. It discusses changes and thickness of the brain at different stages, and how this translates to the real world. During puberty, there is increased connectivity between the prefrontal cortex, which is involved in motivation and decision-making, dopamine centers and the amygdala. This integration and testing of circuits for emotions and reward as they relate to decisions is the key element of the article.

Adolescence and teen years are a time of testing social and physical interactions with the world. This is often accompanied by unsafe behavior, which cannot be justified by the underlying neurology. Neuroscience has shown that during this time, there is increased connectivity between areas of the brain related to emotionality and threat detection, such as the amygdala, as well as reward. This is a heightened stage of development in which different behaviors are tested to see how they lead to success or fear states. It is also a time when the body is more capable of deliberately planning dangerous activities, such as accessing medications. Therefore, it is important to lock up all medications to prevent access.

Puberty is a time in which the internal state of the person or animal is being sampled and tested against different exteroceptive events. Now, they are able to guide those events with more urgency. It’s no longer just about whether or not the caregiver is bringing milk or food. The biology doesn’t care about the source. The teen is able to sample many more exteroceptive events through behavior. This theory suggests that one of the motivations is to learn to mitigate the risk of famine and malnutrition. As teenagers get older, they start to question their parents and whether they are the greatest thing ever or the worst thing ever. So, you can start to map the neurology onto some of this emotional exploration.

The recommendations that map to the biology of teens include later start times in schools to match their shifts in circadian rhythms and the need for extended sleep, as well as sleep interventions for youth who are at increased risk for mental health problems. Almost every mental health issue is supported by getting regular quality sleep of sufficient duration, which will vary from person to person.

When assessing teens, it is important to consider whether or not they can feed and support themselves. Although rarely the case, some teens are forced to take care of themselves due to parents and other caretakers not being available. Leveraging different kinds of social relationships that reinforce positive behavior is also recommended.

During puberty, the goal is to encourage as many safe forms of interaction that allow children, teens, and adolescents to test their autonomy. This allows them to make good assessments about the exteroceptive events they are selecting, and how those make them feel internally. Adolescence and puberty is seen as a period of development in which one self-samples for the two elements discussed at the beginning: how to form bonds and how to make predictions about what will make them feel good at a level of interoception.

Though it may sound transactional, relationships can access things that one couldn’t do before, such as cooperation, teamwork, and more. Physically, it is clear that these hormone and peptide changes in the brain and body trigger more autonomy and physical capability.

A discussion about emotions would not be complete without talking about the right brain, left brain stuff. There’s a theory of emotional development that I find particularly interesting, which is from Allan Schore at UCLA, that talks about how most of our testing of bonds and relationships is this seesawing back and forth between very dopaminergic or serotonergic, driven by dopamine or serotonin states. This starts with infant and mother or infant and father. During development, healthy emotional development clearly begins with an ability for the caretaker and child to be in calm, peaceful, soothing, touch-oriented, eye gazing type of behaviors. Those really drive serotonin, the endogenous opioid system, oxytocin, things are very calming and are centered around pleasure with the here and now, as well as excited states of what we’re going to do next. There’s actually a characteristic sign of the dopaminergic interaction, where both caretaker and child are wide-eyed, the pupils dilate.

And that nonetheless brings us back to the exact same model that we started with in infancy, of alert or calm, feel good or feel bad, primarily exterocepting, primarily interocepting. So I keep going back to this, I’m sort of like a repeating record on that, because the same core algorithm, the same core function is at play throughout the lifespan. This is a useful framework in my opinion, because it allows you to sort through all the data and information that’s out there about, well, this area, the astria terminalis is active or the basal lateral amygdala is active or gray matter thickening or this hormone or that hormone, and return to a kind of kernel of certainly not exhaustive truth, it doesn’t cover all aspects of emotionality, but at least establishes some groundwork from which you can start to evaluate how different behaviors might or might not make sense, how certain emotional responses might or might not make sense, regardless of the age of the person or the organism.

That’s a signature of arousal – they get really excited and oftentimes the baby will look away if it gets really excited. These are signatures of dopamine release in the body, and in adolescents, these same things carry forward. Good bonds are achieved through hanging around, watching TV, playing video games or texting together or talking, whatever it is that the soothing local activity happens to be, as well as adventure and things that are exciting. This could be sports, it could be shopping, it could be a summer adventure, it could be the next big thing. This kind of seesawing back and forth between the different reward systems seems to be the basis from which healthy emotional bonds are created. For those interested, Dr. Schore’s work is worth looking into. He is a clinical psychologist and psychoanalyst with deep roots in neuroscience. His book and language around right brain, left brain is also fascinating.

The right brain is thought to be the emotional side, characterized as holistic, emotive, and synthetic. The left brain is thought to be logical, sequential, and analytic. However, according to Schore, this is false. There is no neuroscience evidence to support this claim. To have a discussion about emotion, it is important to know the differences between the left and right brain. For right-handed people, the left brain is linguistically dominant, meaning most language is centered in the left side of the brain.

Left-handers who were forced to become right-handed may still have language mostly in the left side of the brain. This is because when language gets laid down in the brain, it is distributed between both the left and right sides. Right-handers typically have most of their language coming from the left side of the brain, while left-handers may have language that is more evenly distributed. There are variations depending on whether someone is a hook righty or a hook lefty. Generally, language is centered in the left side of the brain and includes lexicon, grammar, and syntax. However, there is one aspect of language that seems to be more right brain.

There seems to be some arithmetic advantage in the left side of the brain. This was discovered through experiment and it is very good at manipulating spatial things and visual spatial tasks, but it is linguistically primitive except for one aspect: prosody, which is the lilting and falling of language. Most people don’t realize this because the right brain is always described as the emotive side, and it is super emotional and holistic. There isn’t a ton of evidence for this, but the evidence is strong.

I don’t speak Italian, but I only know a little bit of it. Most of what I know is when my Italian colleagues have said to me: [speaks in foreign language], which means, “What are you trying to say? What are you saying?” I think I’m getting that right. Basically, they’re saying that I don’t speak Italian, which is true.

My Italian colleagues also often say [speaks in foreign language], which means “big, lazy guy” – an accurate description of my friend Costello. Even with those few examples, there is a lot of LILt and fall in Italian – more so than in other languages.

One of the reasons I find Italian so beautiful is the prosody and shifts in intonation when other people speak. It’s almost like listening to a singing song.

I used to like to go to scientific meetings and would always hang out with the Italians. This was because I had some good friends in Italian labs, but also because they always knew where the best food was – their standards for food were incredible. They would rather starve than eat terrible pasta and the pasta they did find and were willing to eat was always fantastic. In addition to that, they always brought a guitar, making them a lot more fun than a lot of my other colleagues to hang out with at meetings.

This discovery of the right brain doing things that are more about manipulating spatial information was made in split-brain patients, who lack connection between the two sides of the brain. This had to be teased out through very complicated experiments by people like Roger Sperry, who won a Nobel Prize for this, and Mike Gazzaniga, who figured out these lateralized differences. However, let’s try and demolish the myth that the right side is synthetic and holistic and emotive, and that the left side is logical, sequential, and analytic – that you’re a left brain person or a right brain person. I will talk about this more in a future episode.

Nothing could be further from the truth. There is no scientific evidence to support that. A few lesion studies can tease out effects that make one think that’s what’s happening, but careful work points in a totally different direction.

We cannot have a complete conversation about emotions, bonds, and social connection without talking about oxytocin. Oxytocin has become very prominent in the last decade and seems to be everywhere. Whenever one hears a discussion about neuroscience or hormones in the brain, oxytocin is released. It is released in response to lactation in females, sexual interactions, and non-sexual touch in both males and females. It is involved in pair bonding and the establishment of social bonds in general. How it does that seems to be by matching internal state. It increases synchrony of internal state, possibly setting a level of calmness or alertness.

That seems like a reasonable hypothesis, as well as raising people’s awareness for the emotional state of their partner. In order to form good bonds, we need to pay attention to how others feel and evaluate whether there is synchrony between states. Oxytocin increases this synchrony and awareness for the emotional state of others. Mirror neurons were discovered for their ability to respond when people engage in certain physical actions, but the same neurons would respond when someone else watched someone else perform the same action. Mirror neurons are controversial, with many neuroscientists believing the data was over interpreted in terms of empathy and assigning value to the emotional states of others.

My opinion is that there are neurons in the brain that clearly represent the actions of others. However, it is not clear that they are wired into the emotion and empathy system in any direct way. The growing consensus is that the data does not support the concept of mirror neurons. Keren Haroush at Stanford discovered neurons in the brain that point to the fact that primate species are making assumptions and trying to predict the behavior of other members of their species. This is an experiment related to the prisoner’s dilemma, where one member of a given interaction cooperates and the other one does not. There seem to be neurons that are doing these sorts of predictions or computations. Instead of thinking about mirror neurons, it is more correct to think about neurons that are trying to predict the behavior of others.

Emotions are core features of establishing bonds between people and predicting behavior. Oxytocin is a component that helps us to understand and predict other’s behavior as well as guide our own. Intranasal oxytocin has been administered in experiments in order to increase the depth of bonding. It has been reported that this increases positive communication among couples, although it is not recommended to take intranasal oxytocin without a prescription.

A study published in Biological Psychiatry titled “Intranasal Oxytocin Increases Positive Communication and Reduces Stress Hormone Cortisol Levels During Couple Conflict” suggests that oxytocin is the “trust hormone”. This 2009 paper found that when couples were administered oxytocin before fighting, they experienced a greater sense of connection and intimacy. Additionally, studies have been conducted using autistic children to see if intranasal oxytocin can help them establish better social connections and “empathy” or theory of mind. While it is clear that oxytocin has general effects, the nuances of each situation are still unknown.

Oxytocin and ketamine have been combined in a marketed nasal spray. I have no idea why one would want to do this, as ketamine is a dissociative anesthetic used for the treatment of PTSD, and was previously used as a recreational drug. It is similar to PCP, and can be quite dangerous. I am uncertain why these two substances would be combined, but it is interesting to note that it is happening.

A recent study published in the journal Neuroscience found that oxytocin modulates social distance between males and females. The study gave oxytocin to people in monogamous relationships and evaluated the extent to which the males paid attention to attractive potential partners. The takeaway from this study is that oxytocin administration seemed to promote monogamous behavior and discourage foraging for new mates. The experiments may be artificial, but the general theme is that oxytocin promotes pair bonding, understanding of the internal state of others, and enhanced exteroception for those particular people. If increasing oxytocin is the goal, there is some evidence that supports this.

I invite you again to go to examine.com or another such site like PubMed if you want to forage for more information on oxytocin. It appears that vitamin D is required for proper production, and in some cases can increase levels of oxytocin when supplemented, which is interesting. Believe it or not, melatonin, an old friend that I have pushed back against as a supplement for sleep due to what I view as untoward side effects, may prime the system for slightly increased oxytocin release. There is even one report that low doses of caffeine could increase oxytocin release, but this result is not very robust. Therefore, you should always read past the titles and the abstracts and get into the meat of the paper. When I did that, the effects were pretty negligible with caffeine on oxytocin. However, it is still interesting that vitamin D and melatonin may have some positive effects on oxytocin release. Many people are taking oxytocin directly through intranasal sprays, but it is usually prescription in most places. Check to be sure.

Vasopressin and oxytocin are two important molecules that our bodies produce for social bonds and emotionality. Vasopressin suppresses urination and was developed as a treatment for diabetes insipidus, a condition where people urinate excessively and risk dehydration. Alcohol consumption inhibits vasopressin and can cause people to excrete large amounts of fluid. I’m not recommending anyone try this, as I have never tried it and do not plan to.

Vasopressin has effects on the brain directly, creating feelings of giddy love and increasing memory in very potent ways. There is a whole biohacking community that has been dabbling with vasopressin for some time, although I have never tried it and certainly do not recommend it. Vasopressin is a prescription drug and is a pretty serious compound to start messing with, as it has so many different effects in the body. It is interesting to note that it creates the sense of giddy love and is also used somewhat as an aphrodisiac, similar to oxytocin.

The prairie vole is a small rodent species that has two different populations: some are monogamous and some are non-monogamous. Research has shown that levels of vasopressin and/or vasopressin receptors dictate the monogamy or non-monogamy of the species. There is also evidence in humans that vasopressin and vasopressin levels can relate to monogamy or non-monogamy. We will explore this further in the month on hormones.

The vagus nerve is a connection between the body and the viscera, such as the gut, heart, lungs, immune system, and brain. The brain is also controlling these organs. This is an important factor to consider when discussing the neuroscience of emotions.

The myth that stimulating the vagus nerve always leads to calmness is false. A paper published in Current Biology from the David McCormick Lab at the University of Oregon illustrated that stimulation of the vagus nerve increases dopamine release and activates the brain’s alertness. Therefore, it is a stimulant of alertness and not a calming agent.

Interesting in light of emotionality, work has been done by many groups, in particular, the work of Karl Deisseroth at Stanford, a psychiatrist who has developed tools to adjust the activity of neurons in real time using light and electrical stimulation. An article in the New Yorker was published about this a few years ago, and I’ll put the link in the caption as well.

Vagus stimulation, which was originally developed for the treatment of epilepsy, is now being used for various other purposes and can even increase plasticity. Increasing activity of the vagus increases alertness and it’s incredible to see what happens in real time to emotionality when the vagus is stimulated.

In Deisseroth’s office, he was talking to an extremely suicidal depressed patient who had a small device implanted that allowed her to adjust her vagus nerve activity. She described her previous state as “going pancake,” meaning totally laid out flat, not much going on, and she didn’t want to pursue a job.

The patient, Sally, was suffering from severe depression. The psychiatrist spoke to her in a typical fashion and they discussed her blood pressure, mood, insomnia, bad dreams, and low appetite. Sally requested to increase her vagus stimulation level from 1.2 milliamps to 1.5 milliamps. The psychiatrist agreed and the stimulation began. In the next few minutes, Sally underwent a remarkable change; her frown disappeared, she became cheerful and started describing her pleasure from the Christmas holiday and recounting YouTube videos she had watched. She was still smiling and talking when the session ended, and they walked out to the reception area. This was all achieved through vagus stimulation.

Vagus stimulation is fascinating in terms of the brain-body connection. Contrary to popular belief, it is not all about being calm – it is actually about being alert. This axis of alertness and calmness is one primary axis in emotion, though it is not the only one. There is also the valence component of good or bad, as well as the interoceptive and exteroceptive components. These elements help to explain what the core elements of emotion are and how to manage them. To this end, I have mentioned tools such as the Mood Meter app and oxytocin, as well as ways to conceptualize emotions.

Understanding and regulating one’s emotional state is a powerful tool. To do this, one should think of emotions as elements of the brain and body that encompass levels of alertness, a dynamic with the outside world, and one’s perception of their internal state. This structured way of thinking can help to understand the pathology of feeling anxious, depressed, or other emotions, and to develop a richer emotional experience. It is not necessary to parse every bit of one’s experience in a reductionist way, but it can be a source of knowledge from which to start thinking about emotional life differently. Psychedelic therapies such as psilocybin and MDMA are emerging and will be discussed in depth by an expert guest.

The compounds discussed in this podcast affect aspects of emotionality such as calmness, alertness, valence, and interoceptive and exteroceptive positioning. Rather than just exploring these compounds superficially, it is important to consider them within a structured framework. This will allow us to better understand the universal biological and psychological shifts that occur when these compounds are used clinically. We have covered a lot of material in this episode, equivalent to two or three university lectures. To support the podcast, viewers can subscribe on YouTube and hit the notifications button. New videos are typically released every Monday.

You can subscribe to our podcast on Apple and Spotify, and leave us a five-star review on Apple if you think we deserve it. Please tell your friends, family, and co-workers about the podcast if you think the material would be of interest and informative for them. If you want to send them links, that’s terrific too. We also have a Patreon account (patreon.com/andrewhuberman) where you can support us at any level that you like. In addition, please check out our sponsors and follow the links provided in the captions. That’s the best way to support the podcast. If you have any questions about supplements discussed in various episodes, please reach out.

We have partnered with Thorne because of their high standards for the purity and amounts of the contents in their products. Unlike many supplement companies, Thorne puts in the bottle what is listed on the bottle. To get 20% off any of the supplements Thorne makes, visit thorne.com/u/huberman. Additionally, we would like to thank you for your time and interest in science.