Depressed? Anxious? Happy? Resilient? Thank a hunter-gatherer in your past.

I’ve considered here the high probability that obesity and diabetes are diseases of civilization and the possibility that ADHD may in part be as well. But what about other psychological symptoms and disorders? Randolph Nesse , a distinguished psychiatrist at the University of Michigan, has long been thinking about depression and anxiety in evolutionary perspective, and so have I and others.
Depression is a kind of withdrawal. Although it can be severe or long enough to hurt your reproductive options and even endanger your life, it is sometimes a symptom that gets you out of harm’s way. And it probably always was, for our hunting-and-gathering ancestors.

Let’s say you are pregnant and carrying a three-year-old and thirty pounds of food despite your back pain, or you are challenging someone stronger than you, or you are overly optimistic about driving hyenas away from a carcass so you can steal their meat. If a couple of warning signs send you back to your grass hut with a bad mood on, you live to carry or fight or steal meat another day. If you keep your cocky mood, you may be the meat.

Then too, studies show that depressed moods with their rumination can lead to creative bursts coming out of them, and some of our great leaders–Lincoln, Churchill, Theodore Roosevelt–suffered depression and came back stronger.

Anxiety–which we now know is biologically related to depression–may, in Nesse’s perspective, be a holdover from the pervasive vigilance and wariness that hunter-gatherers may have found essential for survival. For instance, when I lived in !Kung Bushman village-camps, I rarely found anyone sleeping through the night.

Our idea of a good night’s sleep would potentially have been deadly, since the fire would have gone out in front of the hut and the family inside would be vulnerable to lions and hyenas, known at times to attack people in their sleep. So whatever restlessness wakes people up saves lives. Likewise, walking around in the bush while hunting or gathering was no countryside meditative idyll, but a time to be on your guard against predators.

So if generalized anxiety is a pervasive problem of modern life, we might be able to thank our ancestors. This holds true for some symptoms of post-traumatic stress as well. Go through a trauma under evolutionary circumstances–a tussle with a leopard, a bushfire, a losing fight with a rival over a woman–and you may do well to revisit and ruminate over the trauma, at least for a time, and plan how to avoid encounters that might lead to repeating it.

Of course, depression, anxiety, and PTSD can be counterproductive and even debilitating. We don’t need to sit around thinking that we should accept clinical versions of them, just because in some form they may have been adaptive in the past. But there are such things as normal moodswings, and a normal ebb and flow of anxious feelings.

Interestingly, though, in my experience, the !Kung are anxious about things we would recognize. Am I going to be able to continue to feed my family? Is my sister still one of my best friends, or is she pulling away emotionally?–among hunter-gatherers, because of sharing, this question is related to the first. Is the baby’s fever one that comes and goes, or one that will get worse and take her away? And of course: Were those innocent glances my wife and that guy visiting from another band exchanged across the fire, or were they something I need to worry about?

These sorts of things cause anxiety in any culture. Each culture also has its physical dangers, but the !Kung dealt with them much as we deal with the risk of fire in our homes or fatalities on our roads–not by ruminating, but by taking precautions.

And we also owe our hunter-gatherer ancestors a lot of our happiness. Positive psychologists have shown that most people incline toward happiness rather than sadness or even neutrality; most of us, moment to moment, are glad to be alive. So are hunter-gatherers, despite having lives that are much harder than ours. If they weren’t, they couldn’t do what they have to do–and did remarkably well for the many thousands of years that enabled us to be their living legacy.

We also owe them a lot of our resilience. One of the worst ideas in some past versions of psychodynamic psychology is that every bad thing that happens leaves an indelible mark on our minds, impairing us in some enduring way. The reality is that most trauma results in transient symptoms–resilience usually wins the day. Why?

Because if we hadn’t adapted ourselves to hard knocks during evolution, we wouldn’t have survived a single generation, much less hundreds of millennia. We take some things to heart; we grieve; we are afraid. Sometimes we have intrinsic  emotional problems that require psychotherapy or medicine. But more often than not we bounce back, because that is what our evolution built into our psyches–the rebirth of positive mood, the hopeful gaze at the horizon, the leaning into the wind, the determined step forward into the future.

Note: By invitation, I’ve started a blog on the Psychology Today website, and my latest post can be read there or here, although different comments may be  posted there.