Designing the Mind

The Evolution of Depression



Fields like positive, cognitive, and clinical psychology have taught us more and more about our well-being and moods. We know the habits of the happiest people on the planet. We know the chemical correlates of depression. And we know the interventions that are most likely to enhance happiness.

But there is a question I like to ask that is so often neglected in the mind sciences: Why? Why are we happy under certain conditions? Why do we get depressed in others? To answer these questions, we have to go way back in time to the world of our ancestors, and examine it from an evolutionary standpoint.

Positive emotion alienated from the exercise of character leads to emptiness, to inauthenticity, to depression, and, as we age, to the gnawing realization that we are fidgeting until we die.

-Martin Seligman, Authentic Happiness

Psychitects, today we’re going to be exploring the delightful world of depression! Now I’m not cavalier in my treatment of depression—it’s a serious topic that I and many of my friends, family members, and readers, have struggled with. It is out of a deep desire to help that I share the hypothesis that follows.

In my book, Become Who You Are, I propose an answer through what I call Virtue Self-Signaling Theory, which though speculative as a complete theory, is based on sound empirical research and interdisciplinary data, drawing from clinical psychology, neuroscience, clinical psychology, and much more. Though my research, intuition, and experience have made me increasingly confident in the insights that follow, it is ultimately a theory that will take decades to completely validate.

Research suggests that as many as a quarter of people alive today will experience depression at one point in their lives. According to the World Health Organization’s Global Burden of Disease Study, depression is the single most burdensome and disabling disease in the world.¹

Depression is linked to poor physical health, higher rates of heart problems, and higher rates of smoking. Early depression predicts high school and college dropout, teenage pregnancy,² poor marital quality and divorce,³ and failed transition into the work world.⁴

And worse still, incidence of depression is rapidly increasing. Every generation since 1900 has had a greater lifetime risk, and an earlier age of onset for depression than the generation before it.⁵

These trends have been found consistently by just about every measure, including random survey responses, suicide rates, and hospitalization⁶, and the same trends have been found in Puerto Rico, Lebanon, Germany, Canada, Sweden, New Zealand, Taiwan, and many others.⁶ The mental health epidemic is very real.

Here are the core characteristics of depression:

  • Negative mood or loss of affect
  • Low self-esteem, sense of worthlessness
  • Rumination
  • Loss of interest in normal activities
  • Social withdrawal
  • Lack of motivation
  • Confusion and loss of focus
  • Insomnia or hypersomnia
  • Lethargy and low energy
  • And loss of libido

Depression isn’t just a bad mood. It dramatically affects a person’s mood, thoughts, behavior, and physiology. It isn’t just a case of the blues, or all in your head – it appears to be a coordinated set of responses that affect a sufferer’s entire being.

People who are depressed are likely to be in a chronically negative mood. But being depressed doesn’t always mean feeling bad – sometimes it means not feeling at all. Many who are depressed feel numb and empty, lacking pleasure and typical emotional responses to normal stimuli. They cease to get enjoyment from the friends, hobbies, and aspirations that once motivated them. They feel sluggish, distracted, and helpless, struggling to do things that seem like they should be easy.

One of the most unique, important, and overlooked characteristics of depression is a lowered sense of self-esteem, a feeling of personal hopelessness, and the sense that your problems are personal, pervasive, and permanent. People who are depressed are more likely to respond to stress or loss with self-blame, helplessness, and confusion.⁵

Many people assume that human depression must be a dysfunction or a pathological illness. This is the most immediately intuitive explanation. How could a state so miserable and crippling be healthy or functional?

But something doesn’t add up. Given the heritable nature of depression, we would expect the genes that yield it to have been selected against and to make it a rare exception. Yet estimates show that as much as a quarter of the population is likely to develop depression at some point in their lives.¹⁷

Furthermore, pathologies, like dementia or heart disease, almost always increase with age, and this isn’t what we find with depression.¹⁸ It doesn’t become more likely as organs deteriorate—people are most likely to have their first experience of depression by early adulthood.¹⁹

Others assume it is a problem created by the modern, Western world, like obesity.²⁰ But again, this is problematic. Depression appears across cultures, even in indigenous tribes who live in environments very similar to those of our ancestors.²¹

This brings us to the idea that depression is no pathology. It’s not a disease—it’s an adaptation. I know, it seems crazy. It might even seem callous to say a condition with such horrific effects isn’t a disease.

But in order to solve it, we need to understand it clearly.

Depression appears to be a state that we’re all capable of falling into. Despite the fact that some people are more genetically prone to depression, people without this predisposition are still observed to get depressed under the right—or rather, wrong conditions.¹¹

And it doesn’t strike at random. Depression is activated by fairly reliable triggers, such as the loss of a loved one or a job.¹² And it triggers a coordinated set of responses in the body, mind, and behavior.¹³

But depression is truly bewildering from an evolutionary perspective. Why would natural selection favor genes for a state that made us miserable, unmotivated, and worse at nearly everything?

Most people assume that our unique, human traits came about to help our survival. This can be the case, but far more often, our psychological traits and states evolved for a different reason. Evolutionary evidence strongly suggests that our big brains and advanced traits came about largely for social reasons. We evolved to communicate, cooperate, and compete for allies and mates.

The massive pre-frontal cortex that we have is continually using its billions of connections to simulate social possibilities and then to choose the optimal course of action. So the big brain is a relationship simulation machine, and it has been selected by evolution for exactly the function of designing and carrying out harmonious but effective human relationships.

– Martin Seligman, Flourish

Everything from generosity to jealousy to creativity came about to help us contend within the great social landscape around us. We developed these tendencies to impress allies, outshine foes, and attract mates. Initially, this may not seem like the most cheery perspective, but we’re going to learn how important, and how optimistic this view really is.

The human body and mind are the product of millions of years of natural selection. Though most of us aren’t used to thinking in these terms, human nature has been continually crafted to make us the best possible gene propagators in the environment of our ancestors. For this reason, our brains developed a connected set of modules to help achieve certain tasks.

For early humans, a person’s place in their small, hunter-gatherer tribe was crucial. So crucial, in fact, that we evolved a mechanism in our brains to make sure we were in good standing with our community. This mechanism lets us know when we are living in a way that we are likely to get approval, respect, and admiration for. And it lets us know when we aren’t.

I call this mechanism the self-appraisal system. Just like we appraise our homes to determine how valuable others will find them, we appraise ourselves to figure out how valuable others will find us. Our brains are constantly running simulations, raising and lowering the projected worth of the person we present to the world.

The self-appraisal system takes in all kinds of data points, but it is primarily looking for our own behaviors that align, or misalign, with universal human values, like kindness, assertiveness, and ingenuity. From a neurological perspective, we can observe much of this self-evaluating activity through a network called the default mode network.

But we all know it personally through something far more familiar: our internal monologue. The ruminations about our personal strengths, weaknesses, reputation, and worth that we have all experienced, and that some experience on a constant basis.

And the result of this continuous computation is what we usually call our self-esteem. When our brains detect that our social esteem doesn’t look promising, our internal simulator, or self-esteem, will go down as well. This lets us know that something needs to change, but it also brings about a number of cognitive, behavioral, and physiological changes.

So what happens when this mysterious mechanism in our brains sees us in a positive light? For starters, it releases a cocktail of chemicals that have all kinds of effects on us. We feel better, which makes us want to go out into the world and live an active life. We’re more motivated to engage in our interests, hobbies, and responsibilities. And we feel good about ourselves, so we are more confident and outgoing in social situations.

When you think about it, it makes a lot of sense that our brains would create this type of response. If all the evidence we’re seeing suggests that people love us, we’re good at the activities and projects we take on, and we’re likely to attain positive outcomes when we put ourselves out there, we’re going to put ourselves out there. We’re going to live active, social lives and take advantage of every social opportunity we come across. This is good for our genes, so this mechanism has come to play a prominent role in our lives.

But putting yourself out there isn’t always good for your genes. In fact, it can be deadly. If you have traits and behaviors that would cause you to alienate your tribe, offend your allies, or repulse potential mates, the worst thing you can do for your genes is to put these traits on display for all to see. And this is why a low self-evaluation will result in different combinations of chemicals, that bring about different types of behaviors.

When your self-appraisal system decides that your identity needs work, it creates a very different set of behaviors. Instead of making you feel good and motivated, it makes you feel bad and lethargic. Instead of making you want to engage in your favorite activities and interests, it makes you want to stay in bed. Instead of making you want to socialize confidently, it makes you want to withdraw.

People who have depression and low self-esteem are found to automatically adopt risk-averse social strategies. They seek reassurance and keep their social contributions minimal. They avoid drawing attention to their talents, or lack thereof. And they turn away the people that they believe they are likely to disappoint or burden.

Interestingly, people with low self-esteem have even greater anterior cingulate activation, suggesting their brains are more sensitive to social rejection. And in depression too, the brain tends to have greater sensitivity to social rejection, generating a stronger stress response.

– Alex Korb, The Upward Spiral

And this series of chemical and behavioral changes is what we call depression. Yes, I believe depression, however cruel it may seem, is an adapted mechanism – triggered by low self-evaluations, and designed to bring about desirable social outcomes.

Depression seems to promote a loosening of identity. It makes us less attached to the paths we have chosen for building our self-worth on. And ultimately, if our identity really has reached a dead end, if we’ve chosen a path for ourselves that isn’t promising, this can be a good thing.

Some have argued that depression is a pathological disease that causes the symptom of low self-esteem. But I believe this view gets it backward. Depression is triggered by low self-esteem, in the same way that fear is triggered by potential survival threats.

So it isn’t that chemical changes in your brain happen on their own, and then bring about a host of other changes to your mood, behavior, self-perception, and eventually your life circumstances. It is that changes in self-perception, or self-esteem trigger the chemical changes that affect your mood, behavior, and ultimately, your life.

To be clear, we’re dealing with complex, non-linear systems, so all of these factors have the potential to influence the others. But when we look at the mechanism functionally, we see that an initial trigger must be present.

If our brain chemicals just randomly fluctuated in ways that might create crippling moods and behaviors, this would be poison for our genes, and would have been weeded out by evolution millennia ago. All these brain changes are coordinated responses to the context of our environments, behaviors and our interpretations of them.

Depression is the result of identity failure. I want to say it again, because it is extremely important to understand: Depression is the result of identity failure. The self-narrative that you have woven together to understand your past, present, and future, has some plot holes that have become apparent to you.

The depressed person… sees a big discrepancy between what he aspired to in terms of human relations and life goals and what he can achieve in this meager reality. He cannot solve the conflict. What is available is not acceptable to him, and what would be acceptable he cannot grasp. He experiences the tragic situation of having no choice.

– Silvano Arieti, Psychotherapy of Severe and Mild Depression

So what does this mean for you? That you are hopelessly “unapprovable?” That you aren’t valuable to anyone? That no one will ever love you? I know it may feel like this sometimes, but this is absolutely not the case. For one thing, the whole point of the self-appraisal system is to create changes that will help us shift to align with our values. There would be no point for your brain to produce these changes if you were a lost cause.

But there’s an even greater point to be made here. Your brain can only make use of the information it receives and the narratives it has constructed. It has to do its best to form evaluations of you based on limited data, distorted interpretations, and a modern world that scarcely resembles that of the world in which it evolved. This means there are many ways our self-appraisal systems can come to the wrong conclusions. And it’s our job to set it straight.

The same mechanism that is responsible for the awful pits of depression, is also responsible for the highest peaks of flourishing, or eudaimonia.

So what does theory suggest we should do if we’re struggling with depression ourselves? Well, exactly the same thing that existing research suggests: behavioral activation and cognitive therapy. Now I’ve got a video out on CBT, and I plan on putting one out on behavioral activation soon.

But first, I’ll put these practices into the context of the theory I have put forward. We get depressed when our internal, social simulators aren’t seeing evidence of our approvability. And there are two primary reasons why this might be the case.

One is that your brain is not properly receiving the virtue signals that are being sent. You are acting out your virtues on a daily basis, and everyone can see it except for you. This is when you need to use cognitive therapy to un-distort your distorted beliefs, and restructure your view of yourself.

But the other reason is that you are not sending the signal of your virtues through your actions. You simply aren’t taking the actions that make you proud of who you are, and your brain has noticed. This is when behavioral activation – an incremental schedule of activity – can be beneficial. Though it is far from easy when you are in a depressed state, taking baby steps to being more active, whether that means socializing, exercise, or even just getting out of bed and showering, has shown to be more effective than any anti-depressant drug and last longer without any of the nasty side effects.

I’ll be fleshing out this process more in a future video, but for now, I will leave you with a crucial reminder: your well-being is determined by your own self-admiration. If you don’t have that admiration for yourself, the only way forward is to get to work earning it. Find a way to act out your values on a daily basis, and you will gradually climb your way out of the pits of depression, and toward the peaks of flourishing.

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