back to indexEssentials: Science of Stress, Testosterone, Aggression & Motivation | Dr. Robert Sapolsky

Chapters
0:0 Robert Sapolsky
0:23 Positive & Negative Stress; Excitement, Amygdala
2:47 Testosterone & Brain, Aggression, Hierarchy
6:27 Testosterone, Motivation, Challenge & Confidence
11:1 Dopamine, Testosterone & Motivation
13:28 Estrogen, Brain & Health, Replacement Therapies
15:21 Stress Mitigation
19:17 Cognitive Practices for Stress Mitigation, Individual Variability, Consistency
21:36 Stress, Perception & Individual Differences
23:58 Context, Stress & Brain
27:5 Social Media, Context, Multiple Hierarchies
30:15 Acknowledgments
00:00:02.000 |
where we discuss science and science-based tools 00:00:05.720 |
I'm Andrew Huberman, and I'm a professor of neurobiology 00:00:11.760 |
and ophthalmology at Stanford School of Medicine. 00:00:17.920 |
Thank you so much, Robert, for joining us today. 00:00:22.460 |
I want to return to a topic that is near and dear 00:00:27.340 |
What is the difference between short- and long-term stress 00:00:31.060 |
in terms of their benefits and their drawback? 00:00:37.480 |
Basically, sort of two graphs that one we draw. 00:00:41.660 |
The first one is just all sorts of beneficial effects 00:00:52.440 |
The sorts of chronic stressors that most people deal with 00:01:00.100 |
like having spent the last 20 years daily traffic jams 00:01:07.160 |
The other curve that's sort of perpendicular to this 00:01:11.260 |
is dealing with the fact that sometimes stress is a great thing. 00:01:16.660 |
Like, our goal is not to cure people of stress, 00:01:23.980 |
We pay good money to be stressed that way by a scary movie 00:01:30.800 |
What you wind up seeing is when it's the right amount of stress, 00:01:37.800 |
One thing that's really striking to me is how physiologically, 00:01:41.700 |
the stress response looks so much like the excitement response to a positive event. 00:01:48.960 |
But is there anything else that we know about the biology that reveals to us, 00:01:53.780 |
you know, what really creates this thing we call valence, 00:01:57.500 |
that an experience can be terrible or feel awful or it can feel wonderful, 00:02:03.480 |
depending on this somewhat subjective feature we call valence? 00:02:07.900 |
On a really mechanical level, if you're in a circumstance that is requiring that your heart 00:02:15.660 |
races and your breathing is fast and you're using your muscles and some such thing, 00:02:21.780 |
you're going to be having roughly the same brain activation profile, 00:02:27.340 |
whether this is for something wonderful or something terrible, 00:02:30.540 |
with the one exception being that if the amygdala is part of the activation, 00:02:36.340 |
this is something that's going to be counting as adverse. 00:02:39.120 |
The amygdala in some ways is kind of the checkpoint as to whether we're talking about 00:02:46.760 |
Let's use the amygdala as a transition point to another topic that you've spent 00:02:52.520 |
many years working on and thinking about, which is testosterone and other sex steroid hormones. 00:02:59.680 |
How should we think about the role of testosterone in the amygdala, 00:03:03.940 |
given that the engagement of the amygdala is fundamental in this transition point between 00:03:09.240 |
a exhilarating positive response and a negative stressful response? 00:03:15.120 |
Or maybe just broadly, how should we think about testosterone and its effects on the brain? 00:03:20.180 |
Basically, almost everybody out there has a completely wrong idea as to what testosterone does, 00:03:26.500 |
which is testosterone makes you aggressive because males, virtually every species out there, 00:03:32.620 |
have more testosterone and are more aggressive. 00:03:34.820 |
And the reality is testosterone does no such thing. 00:03:40.340 |
And you can see this both behaviorally and in the amygdala. 00:03:43.520 |
It lowers the threshold for the sort of things that would normally provoke you into being aggressive 00:03:51.580 |
It makes systems that are already turned on, turn on louder rather than turning on aggressive music 00:04:03.560 |
It's just upping the volume of whatever aggression is already there. 00:04:07.300 |
And in terms of status and the relationship between individuals, either non-human primates or humans, 00:04:14.680 |
can we say that relative levels of testosterone between individuals is correlated to status within the hierarchy? 00:04:22.780 |
Yes, like you go back, I don't know, whatever number of decades, the endocrinology texts, 00:04:27.600 |
and there were two totally reliable findings in there, which is higher levels of testosterone 00:04:34.360 |
predict higher levels of aggression in punids and other animals. 00:04:38.640 |
Higher levels of testosterone predict higher levels of sexual activity. 00:04:46.000 |
And when you look closely, we've got cause and effect stuff. 00:04:55.800 |
Your levels beforehand are barely predictive of what's going to happen. 00:05:04.360 |
If you have the right type of willing-to-die-in-the-trenches devotion sort of thing, 00:05:11.060 |
watching your favorite team play a sport will raise your testosterone levels 00:05:16.500 |
as you sit there with the potato chips in your armchair. 00:05:19.640 |
So it's not the physicality of aggression, it's the psychological framing of it. 00:05:30.540 |
And a great way to appreciate that is you do a subtraction study, you remove the testes, 00:05:38.480 |
and as I said before, levels of sexual behavior goes down. 00:05:43.900 |
We've just shown that testosterone is somehow causative. 00:05:46.960 |
Critically, they go down, but not down to zero. 00:05:51.280 |
Whether you are a rat or a monkey or a human, whatever. 00:05:56.280 |
And what predicts how much residual sexual behavior is there? 00:06:00.680 |
How much sexual behavior there was before castration? 00:06:05.540 |
What that's telling you is by then, that's behavior that's being carried by social learning 00:06:20.080 |
The more prior history of it, the more it just keeps coasting along on its own, even without 00:06:26.740 |
As I've heard you talk about testosterone today and over the years, I start to get the 00:06:30.760 |
impression that as the most misunderstood molecule in human health in the universe, it's clearly 00:06:40.340 |
It's shifting the way that certain neural circuits work, adjusting the gain on the amygdala, as you 00:06:45.680 |
And is there any truism about testosterone and its relationship to effort or its relationship 00:06:53.760 |
to resilience and in a way that maybe will help me and other people sort of think about how 00:07:08.920 |
The first one is, I think it's a fair summary to think that when it comes to motivation, 00:07:15.660 |
strong behaviors, what testosterone does is make you more of whatever you already are 00:07:22.580 |
Sexual arousal, libido, aggressiveness, spontaneous aggression, reactive aggression, things of 00:07:31.660 |
It's upping the volume of things that are already strongly there. 00:07:34.920 |
Second way to think about it is, well, here's my favorite finding about testosterone. 00:07:45.280 |
And this was some wonderful work by a guy, John Wingfield, who's one of the best behavioral 00:07:53.360 |
And about 20 years ago, he formulated what was called the challenge hypothesis of testosterone 00:08:04.240 |
Testosterone is what you secrete when your status is being challenged. 00:08:09.280 |
And it makes it more likely that you'll do the behaviors needed to hold on to your status. 00:08:17.760 |
If you're a baboon, if somebody is challenging your high rank, the appropriate response on your 00:08:25.700 |
So we've just gotten through the back door, testosterone and aggression again. 00:08:29.580 |
But then you get to humans and humans have lots of different ways of achieving or maintaining 00:08:36.620 |
And all you need to do is go to like some fancy private schools annual auction and you will see 00:08:44.500 |
all these half drunk alpha males competing to see who can give the most money away as a show 00:08:52.240 |
of conspicuous like, you know, property that they have. 00:08:57.360 |
And in a setting like that, I mean, I haven't been able to take urine samples at those times, 00:09:03.220 |
unfortunately, but that shows the flip side of it. 00:09:06.820 |
If you have a species that hands out status in a very different sort of way, testosterone is 00:09:13.900 |
So that generates a totally nutty prediction. 00:09:17.860 |
Take people in a circumstance, say playing an economic game where you get status by being 00:09:24.220 |
trustworthy and being generous in your interactions with the game. 00:09:28.100 |
If you give people testosterone, does that make them more generous? 00:09:36.640 |
And if we have a societal problem with too much aggression, the first culprit to look at is 00:09:44.940 |
The first to look at is that we hand out so much damn elevated status for aggression in 00:09:55.800 |
So like some subtler behavioral effects, you give testosterone to people and they become more 00:10:06.880 |
People pay to take all sorts of nonsensical self-help courses. 00:10:14.880 |
Unless testosterone makes you more confident, that is inaccurate. 00:10:20.240 |
And you're more likely to barrel into wrong decisions. 00:10:24.240 |
What's shown in economic gameplay is that testosterone, by making you more confident, makes you less 00:10:35.980 |
Testosterone makes people cocky and impulsive. 00:10:43.180 |
But if in the others, you're absolutely sure your army is going to overrun the other country in three days. 00:10:53.920 |
Testosterone altering risk assessment beforehand probably played a big role in that kind of 00:11:02.280 |
I always think about testosterone and dopamine being close cousins in the brain because of 00:11:08.140 |
dopamine's salient role in creating this bias towards exteroception. 00:11:14.580 |
You know, when somebody takes a drug that increases dopamine or their chock-a-block full of dopamine, 00:11:20.120 |
they tend, I want to highlight tend because this is, I'm really generalizing here, but they tend 00:11:24.940 |
to focus on outward goals, you know, things beyond the boundaries of their skin. 00:11:29.660 |
And testosterone seems to do a bit of the same. 00:11:33.620 |
It tends to put us into a similar mode of perceiving the outside world in ways that we're asking 00:11:40.800 |
questions like, how do I relate to this other of my species? 00:11:46.840 |
Is there anything that we can do to better conceptualize the relationship between testosterone 00:11:54.740 |
Well, I think it's got lots to do with sort of this massive revisionism about dopamine. 00:12:01.040 |
Everyone since the pharaohs got brought up being taught that dopamine is about pleasure and reward. 00:12:11.780 |
And it's about generating the motivation, the goal-directed behavior needed to go get that 00:12:18.380 |
And before you know it, you're using like elevated dopamine your entire life to motivate you to 00:12:24.880 |
do whatever is going to get you like entry into heaven after life's kind of, you know, it's 00:12:35.360 |
And what testosterone does, even in individuals who are not aggressive and why testosterone replacement 00:12:41.500 |
is often a very helpful thing for aging males, is it increases energy. 00:12:47.320 |
It increases a sense of there-ness, of presence, of alertness. 00:12:53.980 |
Testosterone within minutes increases glucose uptake into skeletal muscle. 00:13:00.660 |
You're just more awake and alert and all of that. 00:13:04.620 |
And that has a lot to do with what dopamine does. 00:13:06.760 |
And as one might predict then, getting just the right levels of testosterone infused into 00:13:17.440 |
They will never press to get infused into the range that optimizes dopamine release. 00:13:30.780 |
You know, we don't hear as about estrogen as often, and yet estrogen has a very powerful 00:13:37.000 |
effects on both the animal brain and on the human brain of males and females. 00:13:41.840 |
Are there any general themes of estrogen that are that people should be aware of or that you 00:13:50.220 |
Is it really all about feelings and empathy and making us more sensitive? 00:13:57.000 |
If you had a choice in the matter between having a lot of estrogen in your bloodstream or not, 00:14:06.500 |
It stimulates neurogenesis in the hippocampus. 00:14:16.400 |
It decreases inflammatory oxidative damage to blood vessels, which is why it's good for 00:14:22.640 |
protecting from cardiovascular disease in contrast to testosterone, which is making every 00:14:29.700 |
Estrogen is one of the greatest predictors of protection from Alzheimer's disease, all of 00:14:38.720 |
Just keep continuing what your body has been doing for a long time versus let the whole 00:14:45.480 |
thing shut down and suddenly try to fire up the coal stoves at the bottom of the basement 00:14:56.640 |
I guess it raises the question about testosterone replacement too, whether or not people should 00:15:01.560 |
talk to their doctor before too long, men and women talk to your physicians before too long 00:15:08.460 |
to avoid these, whatever is happening in these periods where there isn't sufficient testosterone 00:15:15.620 |
Sounds like it could cause longer term problems even when therapies are introduced. 00:15:23.800 |
You described a study once about two rats, one running on a wheel voluntarily, one who's 00:15:35.140 |
basically stuck in a running wheel and is forced to run anytime rat number one runs. 00:15:40.720 |
So in one case, the rat is voluntarily exercising and in the other case, the rat is being forced 00:15:46.800 |
to go to PE class, so to speak, and seeing divergent effects on biology. 00:15:52.840 |
What do you think about stress mitigation and what should we do as individuals and as families 00:15:58.880 |
and as a culture to try and encourage people to mitigate their stress, but in ways that are 00:16:05.000 |
not going to turn us into rat number two, where we're being forced to mitigate our own stress 00:16:10.660 |
And what you see is rat number one gets all the benefits of exercise. 00:16:16.300 |
Rat number two gets all the downsides of severe stress with the same exact muscle expenditure 00:16:24.080 |
and movements going on, perfectly yoked, great example that it's the interpretation of your 00:16:31.200 |
Anything I should say here, I should preface with I'm reasonably good at telling people what's 00:16:39.200 |
going to happen if they don't manage their stress, but I'm terrible at actually like managing 00:16:47.640 |
I'm much better with the bad news aspect of it. 00:16:50.360 |
But some people have massive stress responses, others not at all in between, enjoy it. 00:16:56.940 |
Like what are the building blocks of what makes psychological stress stress? 00:17:01.080 |
And the first one is exactly what is brought up by that running study. 00:17:08.780 |
A sense of control makes stressors less stressful. 00:17:12.920 |
Related to that is a sense of predictability. 00:17:23.880 |
You take a rat who's getting shocked and it can gnaw on a bar of wood. 00:17:31.060 |
Unfortunately, if you have a rat or primate or human and they're stressed, the ability to 00:17:38.960 |
aggressively dump on somebody smaller and weaker also reduces the stress response and displacement 00:17:46.120 |
aggression, and the fact that displacement aggression reduces stress, accounts for a huge 00:17:54.100 |
So all of those variables get social support as well. 00:17:58.880 |
Interpreting circumstances as being good news rather than bad. 00:18:02.760 |
So you've got this very simple sort of like take-home recipe of go out and get as much 00:18:08.700 |
control and as much predictability and as many outlets and as much social support as possible, 00:18:15.820 |
And you go out and do that, and that's a recipe for total disaster because it's much, 00:18:22.760 |
And that's why stress management techniques about control and predictability wind up being far 00:18:28.900 |
worse than neutral if you're preaching that to somebody homeless or somebody with terminal 00:18:37.560 |
Tell a neurotic middle-class person that they have the psychological tools to turn, you know, 00:18:44.500 |
hell into heaven, and there's some truth to that. 00:18:47.420 |
Do the same thing to somebody who's going through a real hell, and that's just privileged, 00:18:53.940 |
you know, heartlessness to do that because that doesn't work. 00:19:01.420 |
It takes a lot of work to like do it right because, you know, you do it wrong and it may temporarily 00:19:08.500 |
seem like a great thing, but when it turns out to be completely misplaced faith, you're going 00:19:17.600 |
These days, there's a lot of interest in using physical practices to mitigate stress, 00:19:22.380 |
you know, trying to get out of the ruminating and to some extent take control of neural circuits 00:19:28.940 |
in the brain by using exercise and using breathing and hypnosis. 00:19:35.120 |
What are your thoughts on more, for lack of a better way to put it, more head-centered, 00:19:40.580 |
cognitive approaches to stress mitigation versus kind of going at the core physiology? 00:19:45.500 |
Cold showers now are even a thing to some extent, you know, just to get people stress acclimated, 00:19:53.660 |
Oh, transcendental meditation, mindfulness, exercise, prayer, sort of reflecting on gratitude, 00:20:08.300 |
They work in terms of they can lower heart rate and cholesterol levels and have all sorts 00:20:15.900 |
One is exactly the caveat that comes out of the Gruney Neal study is it doesn't matter how 00:20:22.520 |
many of your friends swear by the stress management technique. 00:20:25.840 |
If doing it makes you want to scream your head off after 10 seconds, that's not the one that's 00:20:32.300 |
So, you know, read the fine print and the testimonials, but it's got to be something 00:20:37.620 |
Another one is the stress management type techniques that work. 00:20:46.140 |
You can't save them for when you're stuck on hold on the phone with Muzak for two minutes. 00:20:51.580 |
It's got to be something where you stop what you're doing and do it virtually daily or every 00:21:01.320 |
Whatever stress management technique you then do in those 20 minutes short of who knows what, 00:21:06.880 |
you're already 80% of the way there simply by having decided your well-being is important 00:21:13.380 |
enough that you're going to stop every single day and have that as priority. 00:21:18.420 |
So there's no magic breathing tool or exercise. 00:21:25.160 |
And again, we come back to this idea that it's the one that you select and the one that you 00:21:29.400 |
make space for, and it's the one that you hopefully enjoy that's going to work best in terms of 00:21:36.220 |
That brings me to this question of, I find it amazing that how we perceive an event and whether 00:21:44.140 |
or not we chose to be in that event or not can have such incredibly different effects on 00:21:52.160 |
circuitry of the brain and circuitry of the body and biology of cells. 00:21:59.620 |
Like how can a decision made presumably with the prefrontal cortex, although other parts of 00:22:04.740 |
the brain as well, how can that change essentially the polarity of a response in the body? 00:22:11.840 |
And I mean, you've talked before about type A personalities and we don't have to go into 00:22:16.160 |
all the detail there for sake of time, but it is interesting that the effects of endothelial 00:22:21.380 |
cells, I mean, literally of the size of, of the portals for blood are in opposite direction, 00:22:28.780 |
depending on whether or not somebody wants to be in a situation as a highly motivated person. 00:22:33.900 |
Maybe you could just give us the top contour of, of that. 00:22:36.480 |
And then maybe if you would, you could just speculate on how the brain might have this 00:22:42.300 |
switch to turn one experience from terrible to beneficial or from beneficial to terrible. 00:22:51.680 |
You can think autonomic regulatory neurons into action in ways that only other animals can do 00:22:59.720 |
with like extremes of environmental circumstances. 00:23:03.320 |
You, we talk about the optimal amount of stress that counts as stimulation. 00:23:08.680 |
And in general, that stress, that's not too severe and doesn't go on for too long. 00:23:16.660 |
And in those conditions, we love being stressed by something unexpected and out of control and 00:23:22.440 |
predictability, like a really interesting plot turn in the movie you're watching. 00:23:27.800 |
But you get the individual differences that somehow has to accommodate the fact that for some people, 00:23:34.120 |
the perfect stimulatory amount of stress is like getting up early for an Audubon birdwatching 00:23:41.660 |
next Sunday morning and for somebody else, it's signing up to be like a mercenary in Yemen and 00:23:48.300 |
tremendous individual differences that swamp any simple, you know, prescriptions. 00:23:58.240 |
The prefrontal cortex, this thinking machinery that we all harbor, it's such a double-edged sword. 00:24:04.880 |
And, uh, what's remarkable to me is how the areas of the brain, like the hypothalamus and 00:24:12.900 |
I mean, if you stimulate ventromedial hypothalamus, you get the right neurons and animal will try 00:24:17.540 |
and kill even an object that's sitting next to it. 00:24:20.180 |
You tickle some other neurons, it'll try and mate with that same object. 00:24:24.800 |
I think there are probably rules to prefrontal cortex also, but it sounds like the, the context 00:24:31.160 |
plural from which prefrontal cortex can draw from are, is probably infinite. 00:24:36.900 |
Um, so that we could probably learn to perceive threat in anything, whether or not it's another 00:24:42.400 |
group or whether or not it's, um, science or whether or not it's, uh, somebody's version of 00:24:49.060 |
I mean, it's, it's like you can plug in anything to this system and give it enough data. 00:24:53.840 |
And I think it sounds like you could drive a fear response or a love response. 00:25:00.940 |
To what extent can we toggle this relationship between the prefrontal cortex and these other 00:25:09.740 |
Oh, and an, an enormous amount, um, you know, for example, being low in a hierarchy, um, is 00:25:18.800 |
generally bad for health and like every mammal out there, including us, but we do something 00:25:24.060 |
special, which is we can be part of multiple hierarchies at the same time. 00:25:28.280 |
And while you may be low ranking in one of them, you could be extremely high ranking in 00:25:33.260 |
another, you're like, have the crappiest job in your corporation, but you're the captain 00:25:39.180 |
of the team softball of the softball team this year for the company. 00:25:42.920 |
And you better bet that's somebody who's going to find all sorts of ways to decide that nine 00:25:48.240 |
to five Monday to Friday is just stupid paying the bills. 00:25:51.540 |
And what really matters is, you know, the prestige of the weekend. 00:25:55.520 |
So we can play all sorts of psychological games with that. 00:25:58.560 |
One of the most like consistent, reliable ones that we do and need to use the frontal cortex 00:26:05.260 |
like crazy is somebody does something rotten and you need to attribute it. 00:26:10.960 |
And the answer is they did something rotten because they're rotten. 00:26:14.820 |
Always have been, always will be this constitutional explanation. 00:26:30.420 |
We're best at excusing ourselves from bad things because we have access to our inner lives. 00:26:37.160 |
And we've got prefrontal cortexes that are great at coming up with a situational explanation 00:26:42.960 |
rather than, hey, maybe you're just like a selfish, rotten human. 00:26:50.400 |
We do that every time we don't let somebody, you know, merge in the lane in front of us, 00:26:57.620 |
even though you curse somebody who does the same thing to you and, you know, endlessly. 00:27:05.080 |
Your statement about the fact that we can select multiple hierarchies to participate in, to me, seems like a particularly important one nowadays with social media being so prevalent. 00:27:18.760 |
But what's interesting about social media, I've found, is that the context is very, very broad. 00:27:24.860 |
As you scroll through a feed, you are being exposed to thousands, if not millions of contexts. 00:27:31.940 |
This meal, that soccer game, this person's body, this person's intellect. 00:27:41.740 |
Whereas I'm assuming we evolved, I think we did evolve, under contexts that were much more constrained. 00:27:47.220 |
We interacted with a limited number of individuals and a limited number of different domains. 00:27:51.780 |
But now more than ever, our brain, our prefrontal cortex, and our sense of where we exist in these multiple hierarchies has essentially wicked out into infinity. 00:28:03.580 |
How do you think this might be interacting with some of these more primitive systems and other aspects of our biology? 00:28:12.140 |
Well, I think what you get is, in some ways, the punchline of what's most human about humans, which is over and over, we use the exact same blueprint, the same hormones, the same kinases, the same receptors, the same everything. 00:28:31.320 |
We're built out of the exact same stuff as all these other species out there. 00:28:35.980 |
And then we'll go and use it in a completely novel way. 00:28:39.220 |
And usually in terms of being able to abstract stuff over space and time and dramatic ways. 00:28:48.460 |
So, okay, you're a low-ranking baboon and you can feel badly because you just like killed a rabbit and you're about to eat and some high-ranking guy boots you off and takes it away from you. 00:29:00.640 |
And you feel crummy and it's stressful and you're unhappy. 00:29:04.300 |
We are doing the exact same things with our brain and bodies when we're losing a sense of self-esteem. 00:29:13.140 |
But we can do it by watching a movie character on the screen and feeling inadequate compared to how wonderful or attractive they are. 00:29:21.980 |
We can do it by somebody driving past us in an expensive car and we don't even see their face. 00:29:28.800 |
And you can feel belittled by your own socioeconomic status. 00:29:32.460 |
You can watch the lifestyles of the rich and famous or read about what Bezos is up to and for some reason decide your life is less fulfilling because you didn't fly into space for 11 minutes. 00:29:47.920 |
And so you can feel miserable about yourself in ways that no other organism can simply because we can have our meaningful social networks include like the party you're reading about on Facebook that you weren't invited to because it's taking place in Singapore and you don't know any of those people. 00:30:08.120 |
But nonetheless, somehow that could be a means for you to feel less content with who you've turned out to be. 00:30:15.840 |
Very grateful to you for this conversation today. 00:30:21.700 |
And for me, it's really been a pleasure and a delight to interact with you today and over the previous years, I should say, as colleagues. 00:30:30.640 |
And thank you again, Robert, for everything that you do and all the hard, hard work and thinking that you put into your work, because it's clear that you put a lot of hard work and thinking and we all benefit as a consequence.