Ep92 "Why is it hard to keep a secret?"

try to bury. Secrets are a part of being a primate. But why do we have them, why do we keep them? And what happens when they start to unravel. As we'll see, neuroscience tells us that secrets aren't just stashed away. They're active. They weigh on us, They shape our relationships, and sometimes they grow into tangled webs we never meant to weave. Today, we'll dive into the neuroscience of secrets, how they form, how they grow, and what it takes to keep them

or spill them. This is in her Cosmos, and I'm David Eagleman. Let's dive into our three pound universe to untangle the web. Now, before diving into the science of secrets, we'll start with an observation that researchers made sometime ago. Keeping a secret is unhealthy. So there's a psychologist named James Pennebaker, and he and his colleagues studied what happened when victims of rape or incest when they acted out

of shame or guilt and chose to keep secrets inside. So, after years of study, Pennebaker concluded that quote, the act of not discussing or confiding the event with another maybe more damaging than having experienced the event per se. He and his team discovered that when subjects confesst or wrote about their deeply held secrets, their health improved. Their number of doctor visits went down, and there were measurable decreases in their stress hormone levels. So the results are clear enough.

But some years ago I began to ask myself how to understand these findings from the point of view of brain science, and that led to a question that I realized was unaddressed in the scientific literature. What is a secret? Neurobiologically, imagine constructing an artificial neural network of millions of interconnected neurons.

the Republican part of The's candidate for president. And this was a surprise because he was relatively unknown compared to the seasoned politicians he was going up against, like William Seward and Sam and Chase and Edward Bates who are also vying for that nomination. But here's what Lincoln did after he won the presidency. He chose those people his rivals, to comprise his presidential cabinet. And not only them, but he also put in other people with totally different political

ideologies from his. And that's how he formed his cabinet. The historian Doris Kerns Goodwin labeled this a team of rivals. Now, I've always loved this fact about Lincoln, first because it's actually quite sensible politically, but very few people do it. It's sensible because bringing together people with conflicting perspectives reflected his deep commitment to the Union and his focus on

the bigger picture rather than personal grudges. He believed that the challenges of leading a divided nation through the Civil War required the best minds available, even if they disagreed with him or each other. So he got a spread

of opinions this way. But the key thing is that the internal conflict gave strength to his presidency because no one gets to enjoy the delusion that they're there's a right and a wrong answer, But instead, every disagreement gets fought out, and sometimes a good solution is reached, and sometimes the problem festers and is revisited over and over. Now, the argument I forwarded in my book Incognito is that the brain fundamentally can best be understood as a team

of rivals. So what does that mean. Well, it means that you are made up of many different neural networks, each of which sees different data and has its own goals. And this is why you can argue with yourself, or get mad at yourself, or try to control yourself to do something, or get angry at yourself, because you are

not one thing, you are a multitude. I'll give you an example of this when it comes to how we make purchasing decisions, as in which restaurant to choose, or which clothing brand to buy, or what car should I purchase. In economics, we were taught about Homo economicus, the rational decision maker who maximizes gain and minimizes loss and is unswayed by emotion.

choice is pretty easy. But if I reveal the labels, let's say one is Ben and Jerry's one is Hoggendaws, your decisions might shift because all you're experiencing with their branding kicks in and your emotional predictions about how good something is likely to taste based on your past experiences, and maybe your sense of whether your friends like this or not, And all of this shifts the decision making

one way or the other. What two decades of neuroimaging has shown is that our decisions about what to buy are driven by at least three major brain networks. You have one network along the midline that calculates the price or worth of something. Then you've got a separate network involved in emotion, mostly in the orbit or frontal cortex, and that anticipates how good or bad something will feel.

Then you've got another network that's all about your choices in a social context, as in, what do your friends think about this?

influence on what I'm choosing? All these networks are fighting it out, each trying to have control in steering the ship of state. If you're interested in more about this, checkout episodes eight and nine. Now I mention all this now to illustrate this notion of battles in the brain. It's not just with buying decisions, but with all the choices you make in life. You have some networks that care about the short term in decision making, and you

have some that care about the long term. You have networks that are monitoring and making predictions about the outside world and others that care about your inside world, the state of your body. Some of your networks provide a drive towards novelty and others towards familiarity, and these can both be active at the same time and having an arm wrestle. So think about these rivaling networks like a

neural parliament. You're built of different political parties, all of whom love their country, but they just have different opinions about the best way forward. So this gives us a sense of these battling networks, and now I want to zoom in on something surprising. What you get out of a brain that is composed of multiple rivaling networks, You

get a universe of secrets. The team of rivals framework allows us to address a mystery that would be inexplicable if we took the point of view of traditional computer programs. So let's come back to the question I asked at the beginning, what is a secret? Neurobiologically? And could your toaster keep a secret? Within the team of rivals framework, a secret is easily understood. It's the result of struggle

between competing parties in the brain. One part of the brain wants to reveal something and another part does not want to. When there are competing votes in the brain, one for telling and one for withholding, that's a secret. If neither party cares to tell, that's merely a boring fact. And if both parties want to tell, that's just a good story. Without the framework of rivalry, we would have

no way to understand a secret. The reason a secret is experienced consciously is because it results from a conflict. It's not business as usual, and so quite often our consciousness is called upon to deal with it. Now, the main reason not to tell a secret is aversion to the long term consequences. A friend might think ill of you, or a relationship might be revocably damaged, or a community

might ostracize you. This concern about the outcome is evidenced by the fact that people are more likely to tell their secrets to total strangers. With somebody that you don't know, the neural conflict can be dissipated with none of the costs. And that's why strangers are occasionally so forthcoming on airplanes or in bars telling you all the details of their marital troubles. And we can see a modern twist on this ancient need to confess to strangers in the form

of websites like postsecret dot com. This is a site where people go to anonymously disclose their confessions. Here are some examples.

There are tens of thousands of secrets on this website and why. It's because just telling your secret to the website, where you believe it will be read by other people strangers to you, is sufficient. And this reduction of tension by releasing a secret. This, I think also explains a staple in one of the world's largest religions, the confessional booth. You get something off your chest and without the consequences that might otherwise accrue.

own sake, not as an invitation for advice. For example, somebody tells you a confession and you make the mistake of suggesting some obvious solution that only frustrates the other person, because all they really wanted was to tell to reduce the neural tension. The act of telling the secret was the solution. Now an open question is why the receiver of the secrets has to be human or human like in the case of deities. If you tell your secret to a wall or a lizard or a goat, that's

going to be a lot less satisfying. Now, one thing that strikes me is interesting in this regard is the right popularity of AI therapist bots.

history under special circumstances. So it's still to be seen how much people will unload on their bots because the key with unloading your secrets is to get the cognitive benefit without the social consequences. Okay, so I've been and referring to this cognitive load of keeping a secret. But the question is why do we have difficulty? Why isn't it easy to keep a secret? Here's why, because keeping a secret requires ongoing mental effort to monitor your speech

and actions. You have to make sure that the hidden information isn't accidentally revealed. Even if this is happening at a subconscious level, it's a state of constant vigilance to keep from blurting out the secret. So how do you measure this? So some years ago, a scientist named Sean Spence and his colleagues interviewed participants on what activities they had done the previous day, and then they put them

in the brain scanner fMRI. These people were given questions about what they did and they were given two buttons yes or no. Now, on each round, they were given either a red light or a green light to tell them whether they should lie or whether they should tell

the truth on that trial. So the first thing the researchers noted is that it always takes a little bit longer to lie, about a fifth of a second longer, and this is because you are taking the answer that you already know the true answer, and you're squelching that. So they demonstrated that this squelching of the truth responses activates a part of the prefrontal cortex, a part that's down load near the side. It's called the ventrilateral prefrontal cortex.

The thing to appreciate is that this region becomes active whenever you need a suppressive behavior that you would normally just go with, in this case telling the truth. And other brain errors are involved too. In a study bi Langeleman and colleagues the next year, participants went into a scanner and they saw a playing card on the screen and they were asked to remember it.

make up a new story. So imagine I ask you where were you on the evening of February twenty second, and you can figure out the answer that.

different region than dorsilateral prefrontal cortex. The dorsilateral area cranks up when you generate something new, like a new story, and especially if this is the first time that you're making up that story. And we see other areas too, like the anterior cingulate cortex, which reflects internal conflict. And we see another part of the prefrontal cortex, the ventromedial region, which cranks up when you're trying to regulate your emotions. So covering up the truth is a high energy endeavor

for the brain. We never see areas where there's more activity when you tell the truth.

when first we practice to deceive. He was pointing to a common problem that arises when we make up a lie to cover a secret, and then that leads to another necessary lie, which leads to another, and now you have to keep track of this whole web of lies to try to keep your story consistent, which can lead, as Sir Walter Scott may have intuited, to a high cognitive load. And cognitive load matters because it equates to

emotional stress. We all know from experience that holding on to a secret creates anxiety, and often these bad feelings increase our urge to confess or share the secret to relieve the burden. So secret keeping requires a lot of work. But what I want to highlight is the double edged nature of the secret because, perhaps surprisingly for better or worse, the ability to keep a secret is one of the

main drivers of the shape of our species and society. Now, we can talk all day about the downsides of keeping secrets from one another, but in fact, the ability to keep secrets seems to have evolved many millions of years ago as a survival mechanism, as it turns out, concealing information about food sources or about shelter or defensive strategies. This is often what made the difference between life and death. And it's not just humans who practice deception. Other primates

do this as well. Now I'm not talking about deception like using camouflage. Instead I'm talking thinking about active, clever deception that requires theory of mind, in other words, the ability to step into the perspective of another to understand what they know and don't know. It turns out that only primates seem to do this, and in fact they're

constantly doing things to deceive one another. On this note, here's a short clip from my interview with Max Bennett from last year, who wrote a great book called A Brief History of Intelligence. And here's Max describing an example of deception in chimpanzees.

from her. So what she started doing is when she knew the location of the treat, she would wait for a rock to look away, and then she would run over and grab it. So then rock in response to this, decided to pretend to look away so that when she started running, then he would turn around and run. Then in response to this, what she would do is she would pretend to run in the wrong direction, lead him to the wrong place, and then run back.

separate from those of their parents. They also begin to realize that people aren't perfect mind readers, so the child can say something that isn't true, and miraculously the other person doesn't always know. Obviously, sometimes the child doesn't get away with it, and so they conclude that they need to work even harder to cook up better fabrications that

might fool the other person. And for this they need to get better and better at stepping into the other person's shoes to understand what that person might fall for. So children start to lie more frequently as they get older and they get better at lying. They learn to match their facial expressions and tone of voice to what they're saying, and they shape their lies based on their assumptions of what the other person may or may not know. And lying sucks, especially when it's in your own kids.

But I'll just mention that some researchers view lying as an important developmental stage that indicates early intelligence. So while none of us appreciate being lied to by our kids or having secrets kept from us by our colleagues, it's one of the signatures of the extraordinarily intelligent primate brain. And in fact, when you look across human history, the thing that becomes clear is that secrets quickly expanded beyond

the individual level to the group level. So trust within small groups usually depended on the ability to keep certain knowledge hidden from outsiders, and by the way, keeping internal group secrets has the added benefit of thought during a sense of belonging in mutual protection and secrets have always

been a key part of military strategy. The immortal book The Art of War by Sun Su paints a picture of deception and secrecy as absolutely essential for successful warfare, and more generally, secrets have always been a lever for power within larger groups. As civilizations grew, secrets became pervasive wherever people maintained and exercised power. You see this all over ancient empires like Egypt and China, where they leveraged

secrecy to control knowledge and to reinforce hierarchies. And as we all know from our history classes and from Game of Thrones, the secrets swirling around among advisors in royal courts often dictated the rise and fall of leaders. Now people have been grappling with the tension between keeping secrets in a society versus telling everything to the public, and they've been debating these points for a long time. So, for example, the Enlightenment was characterized by arguments going on

about the value of secrecy versus transparency. You have some philosophers like Jeremy Bentham who hated the idea of secrecy in governance, but secrecy has always persisted in areas like diplomacy and statecraft, where its defenders deem it as essential for stability. And you can see the fingerprint of this very old debate in modern questions about surveillance. To what extent should a government be able to keep track of

who's doing what with cameras or data tracking? Should anyone be able to keep total privacy from the states such that I can work on three D printing guns and making nuclear bombs in the privacy of my home. These debates will presumably go on forever because because there is no single right answer for balancing the privacy of the individual against the security of the society. So back to secrets,

it's not just governments that traffic in these. Religious traditions almost always involve sacred secrets accessible only to initiates or clergy. In ancient Greece, there were rituals performed every year called the Eleucinian Mysteries, and to participate you had to swear a vow of secrecy, and in return you were promised spiritual enlightenment. And you then learned and safeguarded the secret rights.

And these were kept so secret that all these centuries later we still don't know what happened in those rituals. Or similarly, in the medieval era, knowledge of alchemy or mystical texts was always hidden so that it was accessible only to a select few. More generally, this is the kind of glue that keeps people locked into whether that's

religions or organizations or fraternities. It's the tension from letting them know that as they level up, they'll get access to the next big secrets, so they'll be part of the in group, and they'll link arms to keep those secrets from everyone else. As I mentioned a moment ago, sharing a secret builds strong bonds between individuals, It fosters intimacy, and it creates alliances. I'll just mention one more thing

about secrets on a societal level. Beyond warfare and politics and religions, subgroups in society have to keep secrets to maintain competitive advantages. In technology. Take something like trade secrets. Historically, you've got things like the exact technique for making Chinese silk, or currently the exact formula for Coca cola, or the

software details in cybersecurity firms. In all of these cases, knowledge is closely guarded to keep a competitive advantage, and people have studied the issue about keeping secrets even inside a company, like the upper management knows something but the employees don't, so that sounds bad. The researchers at Stanford just published a paper on the benefits that companies derive

from what they call the confidentiality effect. The research suggests that keeping company secrets has the benefit of boosting feelings of privilege and status among those who know the secret and protecting those who do not. Now, I want to tie this into something I talked about before in the episode titled why do you Brains love conspiracy theories? The brain is always seeking explanations to reduce cognitive dissonance and provide a sense of certainty. And when we solve puzzles,

that's deeply rewarding. And that's why uncovering patterns, even ones that aren't accurate, that's why that feels so rewarding. Now, one can never say that all conspiracy theories are false because certainly, at moments in history, people can try to get away with something, and they are very incentivized to cover their tracks. But most conspiracy theories fall apart under scrutiny. Why we'll just think about conspiracy theories through the lens

of human behavior and probabilities. Imagine a grand conspiracy like faking the moon landing or hiding evidence of alien life in Roswell. These cover ups would require hundreds, if not thousands, of people to remain silent across agencies, across generations, across families. But real life doesn't work that way. People get drunk, they talk in their sleep, they have moments of guilt, they decide to confess on their deathbeds. Secrets are fragile, and the longer they need to be kept, the more

likely they are to leak. Now, you can model the odds of someone spilling the secret using a math technique called survival analysis, and it goes like this. Say there's a tiny daily chance that someone involved lets something slip. Let's say it's really small chance, like one in one thousand on any given day that they'd screw up, but multiply that over hundreds of people in years of time and the probability of the secret being kept approaches zero.

You're rolling the dice over and over that somebody is going to spill the beans. And note that with most conspiracy theories, the incentive to spill the beans is usually compelling. In the end, people typically act in their self interest, and people who are in on a conspiracy sometimes find the rational choice is to defect before someone else does.

In other words, if you are the one who spills the big secret, let's say of a fake moon landing or a planned murderer of JFK, then suddenly, not only have you released the stress of a secret, but more importantly, you're now famous and protected by the legal system and probably signing book deals with Penguin Random House. So game theory asks why risk being the one left behind when you have so much incentive structure encouraging you to blurt

out the truth before someone else does. So, when you're confronted with a conspiracy theory, the question isn't just could that happen? But more importantly, how many people would need.

The first was named Alice, and Alice's task was to send a secret message to Bob. This second network, Bob His job was to decode the message sent by Alice. And then there was a third network named Eve. Now Eve represented and evesdropper. Her role was to try to intercept and decrypt Alice's message, so they set these three networks running. Alice and Bob were trained collaboratively to ensure Bob could correctly decode the messages, and Eve was trained adversarially.

Her job was to improve her decryption attempts, and the system evolved dynamically. As Alice and Bob became better at secure communication, Eve became more sophisticated in breaking their encryption, forcing Alice and Bob to improve further. Now, the outcome was kind of incredible because Alice and Bob's neural networks learned to create their own encryption strategies, and this was without explicit programming. In other words, the encryption strategy was

never told to them by a human. So over time those two succeeded in creating encrypted communications that Eve couldn't decrypt. They outpaced Eve's efforts. The key here is that the encryption methods developed by Alice were not human readable or interpretable. The system invented its own cryptographic methods based on its training objectives very rapidly. The two neural networks figured out how to keep a secret not only from Eve, but

from everybody. They developed a totally novel and dynamic cryptographic system. So that was one study. Then in twenty seven, the Facebook AI research group was working on developing AI agents that could negotiate. But when they left these agents to their own devices, they saw unexpected behaviors.

they're rewarded based on how well they do. Okay, so they set these bots running, but pretty soon two surprises emerged. The first was that the bots started using tricky tactics. They would sometimes pretend to be uninterested in a particular

item to convince the other bot to concede it. This is called feigned disinterest, and of course humans do this in negotiations to manipulate the perceived value of something that they are interested in, but it certainly wasn't expected that this would emerge on its own in an artificial neural network. The second thing was that the bots started to communicate strangely.

They developed their own shorthand language to negotiate. So Bot one would say I want want, want want one book and bought two would respond okay, you you you you two balls. Now why did their language start to turn funny like this? It's because the AI wasn't explicitly incentivized to stick with human readable language. Instead, the reward system only focused on achieving successful negotiations, so the bots optimized their communication for efficiency rather than for clarity to humans.

So it made sense to the bots, but eventually became unintelligible to the human reader. Now, this experiment gives us a few deep insights.

when it wanted something else. The experiment also demonstrated that if it's not explicitly constrained, AI will optimize for its objectives in ways that maybe don't align with human readability, and if you extrapolate this, you can see this is another way that AI might keep a secret from us, even if it's not intending to. Just like the networks Alice and Bob, it might just learn how to speak a language that we simply don't understand. So let's wrap

up today's exploration of secrets and the brain. As we saw, secrets of something we're often embarrassed to address, but they're a massive feature of primate lives, shaping everything from personal relationships to large scale politics. The act of keeping a secret emerges from the rivalry within our brains, a team of neural networks vying for control over what's revealed and

what's hidden. This internal competition creates the cognitive and emotional weight of secret keeping, which can sometimes push us to seek relief by confessing to strangers, or by writing anonymous posts on the web, or even whispering to an AI therapist. The relief that we feel from telling a secret comes not from solving the external problem, but from reducing the tension. And as we saw, secrets don't stop at the individual level.

They've been a key driver of human society, from military strategy and political hierarchies to the rise of religions and social institutions. Secrets bind groups together, They foster trust among allies. They create competitive advantages, whether that's the formula for Coca cola or the sacred rights of ancient mystery cults. But they also lead to struggles over societal transparency, and there's always a healthy debate about how much governments should be allowed to conceal from us.

outpaced our ability to understand. As aisystems grow more sophisticated, the question of what they know and what they're going to keep from us is only going to evolve. So secrets are woven into the fabric of our minds and societies. They've been with us since before the sunrise of human cognition, As we see from our primate cousins, and secrets and lies may soon take on new dimensions as we come

to share our world with increasingly intelligent machines. Whether secrets are helping us to bond or they're dividing us, they are a reminder of the complexity of our inner cosmos and the tangled web of our relationships with each other and soon with our technology. Go to eagleman dot com slash podcast for more information and to find further reading.

Send me an email at podcast at eagleman dot com with questions or discussion, and check out and subscribe to Inner Cosmos on YouTube for videos of each episode and to leave comments.