Dr. Robert Sapolsky: Science of Stress, Testosterone & Free Will

Introduction

Andrew Huberman introduces Dr. Robert Sapolsky, a Professor of Biology and Neurosurgery at Stanford University. They discuss his work on stress, hormones, and how different factors impact behavior.

Dr. Sapolsky's Work

• Dr. Sapolsky's laboratory has worked on a variety of topics including stress, hormones like testosterone and estrogen, hierarchy within primate troops, and how things like stress, reproduction and competition impact behavior.

• His work combines elements from primatology with human behavior to unveil how humans as old world primates are controlled by different elements of our biology as well as our psychology.

Science of Life Without Freewill

Dr. Sapolsky discusses the science of life without freewill.

Determined: The Science of Life Without Freewill

• Dr. Sapolsky is close to completing a new book entitled "Determined: The Science of Life Without Freewill."

• During this episode they discuss the science of life without freewill.

Stress Control

Dr. Sapolsky talks about stress control and how it impacts us at both conscious and subconscious levels.

Controlling Stress

• They talk about how best to control stress.

• Stress controls us at both conscious and subconscious levels.

Sponsorship Message - ROKA Sunglasses

Andrew Huberman thanks the sponsors for today's podcast which include ROKA sunglasses that are designed with performance in mind.

ROKA Sunglasses

• ROKA makes sunglasses and eyeglasses that are of the absolute highest quality.

• The aesthetic of the glasses is great and they have a lot of different styles to select from.

Sponsorship Message - InsideTracker

Andrew Huberman thanks InsideTracker, a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and reach your health goals.

InsideTracker

• InsideTracker is a personalized nutrition platform that analyzes data from your blood and DNA to help you better understand your body and reach your health goals.

• Getting regular blood work done is really the only way to understand what's going on in your system at a level that can really inform your decisions about your immediate and long-term health.

Introduction

The host introduces the podcast and mentions the sponsors, InsideTracker and Belcampo.

Sponsors

• InsideTracker is introduced as a sponsor of the podcast. Listeners can go to InsideTracker.com/Huberman to get 25% off any of InsideTracker plans by using the code Huberman at checkout.

• Belcampo is introduced as another sponsor of the podcast. It's a regenerative farm in Northern California that raises organic grass-fed and finished certified humane meats. Listeners can order Belcampo's sustainably raised meats to be delivered to them by using my code Huberman at Belcampo.com/Huberman and entering my code Huberman to get 20% off their first time order.

Interview with Dr. Robert Sapolsky

The host interviews Dr. Robert Sapolsky about stress.

Short-term vs Long-term Stress

• The host asks Dr. Sapolsky about short-term vs long-term stress in terms of their benefits and drawbacks.

• Dr. Sapolsky explains that there are two graphs: one for beneficial effects of short-term stress, such as saving you from a predator or improving focus during a presentation, and one for chronic stressors that most people deal with, such as daily traffic jams or an abusive boss.

• He also explains that sometimes stress is a great thing when it's the right amount, which we call stimulation. There is an optimal level of stimulation where function is at its best, too little leads to boredom while too much leads to stress.

Physiological Response to Stress

• The host brings up how physiologically similar the stress response looks to the excitement response to a positive event. Dr. Sapolsky speculates that the fundamental difference between short-term stress and short-term excitement is some neuromodulator like dopamine.

Conclusion

Overall, this podcast episode discusses stress and its effects on our bodies and minds. It also introduces two sponsors, InsideTracker and Belcampo, who offer products that can help improve health and well-being.

The Role of the Amygdala in Stressful Situations

In this section, the speaker discusses how the amygdala is involved in both positive and negative responses to stressful situations.

The Amygdala's Role in Interpreting Stressful Situations

• When experiencing a stressful situation that causes physical reactions such as increased heart rate and breathing, the brain activation profile is similar whether the situation is positive or negative.

• However, if the amygdala is activated during a stressful situation, it biases individuals towards interpreting it as more negative or adverse.

• The amygdala acts as a checkpoint for determining whether an experience is exciting or terrifying.

Testosterone's Effects on Aggression

This section explores common misconceptions about testosterone and aggression.

Misconceptions About Testosterone and Aggression

• Many people believe that testosterone causes aggression because males typically have higher levels of testosterone than females.

• However, studies show that removing testosterone from mammals decreases levels of aggression.

• Testosterone does not cause aggression but rather lowers the threshold for aggressive behavior to occur more easily.

• In male monkeys, injecting them with testosterone amplifies preexisting patterns of aggression rather than causing new aggressive behaviors.

Testosterone's Effects on the Amygdala

• Testosterone does not cause amygdaloid neurons to spontaneously speak about fear and aggression but instead increases their firing rate when already stimulated.

• It upregulates whatever level of aggression is already present rather than creating new aggressive behaviors.

Contextualizing Testosterone's Effects

This section discusses how testosterone's effects cannot be understood outside of social contexts.

Understanding Testosterone Within Social Settings

• It is impossible to say anything definitive about what testosterone does without considering its relationship to specific behaviors and social settings.

• Relative levels of testosterone between individuals may play a role in determining status and relationships in both nonhuman primates and humans.

Testosterone and Behavior

In this section, the discussion is about testosterone and its relationship with aggression and sexual activity. The conversation also touches on how behavior can affect testosterone levels.

Testosterone and Aggression/Sexual Activity

• Higher levels of testosterone predict higher levels of aggression in humans and other animals, as well as higher levels of sexual activity. However, it's important to note that these correlations are not necessarily causal.

• Sexual behavior raises testosterone levels, while aggression raises testosterone levels as a response rather than a cause.

• Individual differences in testosterone levels don't matter much when it comes to producing interesting implications for social circumstances.

Misconceptions About Testosterone

• There are many misconceptions about the effects of testosterone on behavior, particularly sexual behavior. One misconception is that increasing someone's testosterone by 30% will significantly change their sexual behavior, but this is not the case. Your brain is not that sensitive to fluctuations in testosterone levels.

• Watching your favorite team play a sport can raise your testosterone levels due to the psychological framing of aggression rather than physicality.

Castration Studies

• Castration studies have shown that removing testes causes a decrease in sexual behavior and aggression but not down to zero. The residual behaviors are carried by social learning and context rather than hormones alone.

Early Organizing Effects of Hormones

This section discusses how early exposure to hormones affects the development of circuits responsible for initiating sexual behavior.

Developing Animals Deprived of Hormones

• If developing animals are deprived of certain hormones such as estrogen or aromatized testosterone into estrogen, the circuits responsible for initiating sexual behavior may not emerge and therefore not be sensitive to testosterone later in life.

The Effects of Prenatal Exposure to Testosterone

This section discusses the effects of prenatal exposure to testosterone on adult behavior.

Prenatal Exposure to Testosterone

• Fetal sonograms can detect subtle differences in prenatal exposure to testosterone.

• Testosterone has a significant impact during fetal development, but by adulthood, it becomes less important.

• The D2 index finger to ring finger ratio is more similar in females than males. Males tend to have shorter index fingers.

Effects on Female Aggression

• Females also produce testosterone from the adrenals and other sources.

• Lower levels of testosterone are essential for typical levels of aggression and sexual behavior in females.

• Estrogen and progesterone play a major role in post-parturition aggression, while testosterone plays a smaller role overall.

Conceptualizing Testosterone's Effects

This section explores how we should conceptualize the effects of testosterone on human health.

Truisms About Testosterone

• Testosterone makes you more of whatever you already are when it comes to motivated strong behaviors like sexual arousal, libido, aggressiveness, spontaneous aggression, reactive aggression.

• It upregulates things that are already strongly present.

Challenge Hypothesis

• John Wingfield formulated "The Challenge Hypothesis" which states that testosterone increases in response to challenges or competition.

Testosterone and Behavior

This section discusses the relationship between testosterone and behavior, specifically aggression. It also explores how humans achieve or maintain status and how testosterone affects confidence and risk assessment.

Testosterone and Aggression

• Testosterone is linked to aggression.

• Humans have different ways of achieving or maintaining status, such as through auctions at fancy private schools.

• If a species hands out status in a different way, testosterone will boost that as well.

• The societal problem with too much aggression should be attributed to the elevated status given for aggression rather than testosterone.

Subtle Effects of Testosterone

• Giving people testosterone makes them more generous in economic games where trustworthiness and generosity lead to status.

• Testosterone makes people more confident but can also make them less cooperative by altering risk assessment.

• Elevated levels of testosterone can make people cocky and impulsive.

Relationship Between Testosterone and Dopamine

• Dopamine is not just about pleasure and reward but also about anticipation of reward and generating motivation for goal-directed behavior.

• Testosterone increases energy, alertness, presence, and motivation even in individuals who are not aggressive.

Testosterone and Estrogen

In this section, the speakers discuss the effects of testosterone and estrogen on the body and brain.

Testosterone and Dopamine

• Testosterone activates within minutes, increasing glucose uptake into skeletal muscle.

• Lab rats will lever press to get infused with testosterone in the range that optimizes dopamine release.

• Testosterone and dopamine are deeply intertwined.

Estrogen's Effects

• Men need estrogen as well; low levels can lead to cognitive function loss and decreased libido.

• Estrogen enhances cognition, stimulates neurogenesis in the hippocampus, increases glucose and oxygen delivery, protects from dementia, decreases inflammatory oxidative damage to blood vessels.

• Estrogen is good for protecting from cardiovascular disease.

Post-Menopausal Estrogen

• Studies suggest keeping estrogen levels high after menopause can keep brain health better or decrease risk of dementia, stroke, etc.

• A study on post-menopausal estrogen was cut short because it increased risk of cardiovascular disease, stroke, dementia. Lag time between menopause and administering more estrogen caused bad effects.

Understanding the Complexity of Hormone Receptors

In this section, the speakers discuss the complexity of hormone receptors and how they can set off opposite biochemical cascades. They also raise questions about testosterone replacement therapy and the importance of consulting with a physician before undergoing such treatment.

Hormone Receptor Complexity

• Steroid hormone receptors can set off opposite biochemical cascades when not binding estrogen.

• Estrogen is a catchall term for a bunch of hormones, estrone, estradiol, estriol. How much of each one of them? Natural or synthetic?

• It's often hard to say anything about what estrogen does outside the context of what progesterone is doing.

• The endocrine system for women is much more complicated than that for men because it requires dramatic cyclicity.

Testosterone Replacement Therapy

• Men and women should talk to their physicians before undergoing testosterone replacement therapy to avoid potential long-term problems.

• Understanding how much estrogen is needed at which times and in what form is crucial in determining ideal benefits.

Endocrine Disruptors: Real Phenomenon or Just Hype?

In this section, the speakers discuss whether drops in sperm counts and fertility are due to environmental toxins or social reasons. They also explore the challenges associated with studying endocrine disruptors.

Endocrine Disruptors

• There are concerns that environmental toxins such as BPAs may be causing drops in sperm counts and fertility rates.

• Cross-sectional studies suggest that this phenomenon is real but there are still many unanswered questions.

• The challenges associated with studying endocrine disruptors include identifying which toxins are causing the problem and determining how big of an effect they have.

The Effects of Stress on Biology

In this section, the speakers discuss a study involving rats and the effects of voluntary exercise versus forced exercise. They also explore the impact of stress on biology.

Exercise and Stress

• A study involving rats showed divergent effects on biology between voluntary exercise and forced exercise.

• Stress can have a significant impact on biology, including changes in cortisol levels and immune function.

Stress Mitigation

In this section, the speaker discusses stress mitigation and how humans can start to mitigate their own stress.

Building Blocks of Stress

• The first building block of stress is a sense of control. A sense of control makes stressors less stressful.

• Related to a sense of control is a sense of predictability. Predictability makes stressors less stressful.

• Having an outlet for frustration, such as running on a wheel or gnawing on wood, reduces the stress response.

• Social support is also important in reducing the stress response.

Recipe for Disaster

• Simply getting as much control, predictability, outlets, and social support as possible is not enough to reduce stress. It's much more subtle than that.

Takeaway

• To mitigate stress effectively, it's important to have a nuanced understanding of what causes it and how to manage it.

Stress Management Techniques

In this section, the speaker discusses stress management techniques and how they can be harmful in certain situations.

Control and Predictability

• Predictive information only works in a narrow domain.

• A sense of control is beneficial only if it is a mild to moderate stressor.

• In the face of major stressors, an arbitrary sense of control does not work.

Social Support

• Mistaking social support for mere acquaintanceship or going and demanding supportiveness from everyone around you will not work well.

• Being good friends takes a lot of work to do it right.

Physical Practices for Stress Mitigation

• Using physical practices like exercise, breathing, and hypnosis can help mitigate stress.

• It's important to pick something that we like and take control of it.

Supporting Other People

• Language seems like a wonderful tool but doesn't get into the core of our physiology like something like breathing would.

• The best way to support other people is unclear.

Stress Management Techniques

In this section, the speakers discuss various stress management techniques and how they can be effective in reducing stress levels. They caution against blindly following any technique that may not work for an individual and emphasize the importance of finding a technique that works best for oneself.

Finding the Right Technique

• The effectiveness of stress management techniques varies from person to person.

• It is important to find a technique that works for you and make it a daily or regular practice.

• Making time for stress management techniques every day can lead to significant improvements in overall wellbeing.

• Learning to say no to certain things can also help reduce stress levels.

Warning Against False Claims

• Be wary of anyone claiming their stress management technique is scientifically proven to be better than others.

• Any meditative or reflective practice done regularly can have positive effects on reducing stress levels.

Entry Points to Autonomic Nervous System

In this section, the speakers discuss how our perception of events and decisions we make can affect our autonomic nervous system and stress response. They highlight the importance of understanding these entry points as a means of managing stress effectively.

Understanding Entry Points

• There are many entry points into our autonomic nervous system and stress response.

• Our perception of events and decisions we make can significantly impact our physiological response.

• Type A personalities are an example of how motivation and drive can affect endothelial cells in opposite directions.

Brain's Ability to Switch Perception

• The brain has the ability to switch our perception of an event from negative to positive or vice versa.

• Understanding how the brain does this can help us manage stress more effectively.

Understanding Stress and Physiology

In this section, the speaker discusses how humans can turn on their sympathetic stress response with thought, emotions, and memory. The prefrontal cortex is also discussed as a double-edged sword that can perceive threat in anything.

Sympathetic Stress Response

• Humans can turn on their sympathetic stress response with thought, emotions, and memory.

• The measure of the sympathetic stress response is how much the cortex and limbic system sends projections down to all the autonomic regulators in the brain.

• There are gigantic individual differences when it comes to understanding optimal amounts of stress.

Prefrontal Cortex

• The prefrontal cortex is a thinking machinery that has contextual gain control.

• The context plural from which prefrontal cortex can draw from is probably infinite.

• The prefrontal cortex is responsible for social context and moral relativity.

Testosterone Levels and Success

This section discusses how exercise boosts up testosterone levels. It also talks about a literature back in the 80s or so looking at outcomes of marathons.

Exercise Boosting Testosterone Levels

• Exercise boosts up testosterone levels.

• Winning a marathon does not necessarily predict increased testosterone levels.

Can we tell ourselves that something is good for us even if we're not enjoying it?

In this section, the speaker discusses whether we can convince ourselves that something is good for us even if we don't enjoy it. They also talk about cognitive flexibility.

Cognitive Flexibility

• The speaker mentions that they are not a big fan of long bouts of meditation but have benefited from dedicated breathing and shorter rounds of meditation.

• They ask whether they can tell themselves that these practices are good for them and get their physiology working the way they want.

• The speaker talks about being able to find ways to be satisfied with our performance in situations where we may not have achieved our primary goal.

• They discuss how much control we have over toggling the relationship between the prefrontal cortex and more primitive systems.

Playing Psychological Games with Multiple Hierarchies

In this section, the speaker talks about how humans can play psychological games with multiple hierarchies.

Multiple Hierarchies

• The speaker explains how being low in one hierarchy can be bad for health but humans can be part of multiple hierarchies at once.

• They give examples such as having a low-ranking job but being captain of a softball team or being poor but holding a high position in church.

• The speaker discusses how people tend to attribute their own bad behavior to situational factors rather than personal flaws, which requires using the prefrontal cortex.

Social Media and Broad Context

In this section, the speakers discuss the impact of social media on our brains and sense of self.

Social Media

• The speaker mentions that social media is a broad context where we are exposed to thousands, if not millions, of different contexts.

• They discuss how this can create a funneling effect where we only see information that confirms our existing beliefs.

• The speaker talks about how our brains have evolved to interact with a limited number of individuals and domains, but now we are exposed to an infinite number through social media.

• They question how this might be interacting with more primitive systems in our brain.

The Impact of Social Comparison on Self-Esteem

In this section, the speaker discusses how humans can feel miserable about themselves in ways that no other organism can due to our ability to have meaningful social networks.

Social Comparison and Self-Esteem

• Humans can feel badly about themselves by comparing themselves to others in dramatic ways.

• We can feel belittled by our own socioeconomic status or inadequate compared to someone we see on a screen.

• Our meaningful social networks include things like parties we weren't invited to or people we read about online, which can make us feel less content with who we are.

Restricting Context for Enhanced Creativity and Intellectual Life

In this section, the speaker talks about actively restricting contexts in order to enhance creativity and intellectual life.

Actively Restricting Context

• The speaker asks if the listener takes steps in their own life to actively restrict the contexts in which they think and live.

• The speaker shares their experience of spending three months each year without electricity or phone calls while studying baboons, during which they did 90% of their insightful thinking.

• The speaker mentions a trend towards creating a narrowing of context, citing an example of their 14-year-old niece and her friends putting away their phones during interactions.

Do We Have Free Will?

In this section, the speaker discusses their personal belief that humans do not have free will despite what philosophers and neuroscientists may say.

Lack of Free Will

• The speaker shares their personal belief that humans do not have a shred of free will.

• The speaker explains that our behavior and choices are influenced by various factors such as sensory environment, hormone levels, and neuroplasticity.

• The speaker questions where our intentions come from when we make choices.

The Interconnectedness of Genetics, Evolution, and Behavior

In this section, the speaker explains how genetics, evolution, and behavior are all interconnected. He argues that there is no space for free will in this interconnectedness.

The Interconnectedness of Genetics, Evolution, and Behavior

• All factors that influence behavior are ultimately one factor.

• Talking about evolution's influence on behavior means talking about genetics. Talking about genes' influence on behavior means talking about brain construction or protein coding.

• There is no space for free will in the complex web of influences on behavior.

• There is simply no wiggle room for free will in the interconnectedness of genetics, evolution, and behavior.

Can We Intervene in Our Predetermined Behaviors?

In this section, the speaker discusses whether we can intervene in our predetermined behaviors. He explores whether knowledge of our predetermined behaviors can give us some sense of control.

Intervention in Predetermined Behaviors

• Is it possible to intervene in our predetermined behaviors?

• Can knowledge of predetermined behaviors give us some sense of control?

• The speaker does not believe that knowledge can give us any additional layer of control.

• Change can happen through circumstance but not through volitional change.

Change Can Happen Through Circumstance

In this section, the speaker explains how change can happen through circumstance despite the lack of freewill. He uses examples from sea slugs to refugees to illustrate his point.

Change Through Circumstance

• Change can happen through circumstance.

• The same neurobiology that allows sea slugs to learn and change their behavior is present in humans.

• Understanding that change is possible can change the ability of our brains to respond to optimistic stimuli.

• Enormous change can happen, but we cannot change ourselves volitionally.

The Science of Change

In this section, the speakers discuss how change is difficult but possible and how knowledge can help us be more optimistic and inspired.

Striving to be Better Human Beings

• Change is hard but striving to be better human beings is still worthwhile.

• Knowledge of neurobiology can make us more open to being optimistic about change.

• Understanding that change is possible makes us more resistant to getting discouraged by bad news.

Neuroplasticity and Changing Our Circuitry

• Neural circuits can change in response to experience, shaping our circuitry and making us different machines.

• Learning that prenatal hormone exposure can change the construction of your brain will change your brain right now.

• The knowledge of knowledge is an effector in itself.

Knowledge as a Tool for Change

• Knowledge itself is a tool for change, not just pills or protocols.

• Understanding freewill and lack of it, as well as neuroplasticity, are important concepts for people to embed in their minds.

Determined: A Science of Life Without Freewill

In this section, the speaker discusses his upcoming book on freewill and how he aims to convince readers that there's much less freewill than we used to think. He also talks about the challenges of living without freewill.

Convincing Readers About Freewill

• The book aims to convince readers that there's much less freewill than we used to think.

• The speaker goes through all the standard arguments for freewill and explains why they don't make sense with 21st century science.

• The first half of the book is built around convincing readers that there's much less freewill than we used to think.

Living Without Freewill

• Despite thinking that there's no freewill, the speaker has no idea how to function with that belief.

• The second half of the book is built around wrestling with the challenges of living without freewill.

The Reality of Our Interpretations

In this section, Dr. Robert Sapolsky discusses how we have subtracted the notion of agency from various realms of blame throughout history.

Subtraction of Volition

• Throughout history, we have subtracted the notion of agency from various realms of blame.

• We have been able to subtract out a sense of volition in understanding how the world works around us.

• This has resulted in a more humane society without murderers running amuck on the street.

Writing About Determinism

• Writing about determinism coherently is hard as hell.

• Dr. Sapolsky's upcoming book "Determined: The Science of Life Without Freewill" will explore this topic further.

Conclusion and Support for Research

In this section, Dr. Andrew Huberman concludes his conversation with Dr. Robert Sapolsky and provides information on how to support research on stress and sleep.

Gratitude and Excitement

• Dr. Huberman expresses gratitude for the conversation with Dr. Sapolsky and excitement for his upcoming book.

Supporting Research

• Those interested in supporting research on stress and sleep can do so by supporting the research being done at the Huberman Lab at Stanford.

• Donations can be made through the Make a Donation tab on their website.

Social Media Channels

• Follow Huberman Lab on Instagram and Twitter for science-related information not covered in the podcast.

Final Thoughts

• Dr. Huberman thanks listeners for their interest in science.