Three Reasons Behind Human Stress

FROM THE LECTURE SERIES: Understanding the Mysteries of Human Behavior

By Mark Leary, Ph.D., Duke University

So, what’s the difference between us and animals? Why are we so stressed out and they’re not? Let’s look at three interrelated answers to these questions.

Stressed-out mother with kids playing around her.
Many, if not most, of the things that create chronic stress in our everyday lives, are the recent developments of civilization and culture. (Image: Fizkes /Shutterstock)

Human Environment vs. Animal Environment

The first reason that people are far more chronically stressed out than other animals is because we live in an environment that is drastically different from the environment in which our brains evolved. On the other hand, wild animals live in essentially the same sort of environments in which they have been living for millions of years. So their brains are well adapted to responding to the stressful features of those environments.

Our brains evolved to cope with the challenges of living in a certain kind of environment too, just like every animal. But human beings have developed new environments that are nothing like those in which we evolved. We have created crowded cities and towns, fast-moving vehicles, stimulating electronics, and tedious workplaces. We have also created schools and colleges where students try to cram an infinite amount of information into their brains on which they’re constantly evaluated.

This is a transcript from the video series Understanding the Mysteries of Human Behavior. Watch it now, on The Great Courses Plus.

We have created a new way of living that, in many ways, we aren’t well-suited for. Many, if not most, of the things that create chronic stress in our everyday lives, are the recent developments of civilization and culture.

The things that stress us out, such as traffic jams, computer crashes, and stock market declines, are very recent cultural changes. In some ways, it’s amazing that people manage in their new environment as well as they do.

Of course, many of the advances and innovations that stress us out have also improved our lives immensely. We wouldn’t want to go back to a time before we had modern science and technology. But modern science and technology also create a stressful environment that our prehistoric ancestors didn’t have to deal with during the course of human evolution.

Learn more about how human nature evolved.

Stress and Uncertainty

The second reason that many people are stressed out involves the fact that we live with a great deal of uncertainty regarding whether life is going well. Animals in the wild live in what’s called an immediate-return environment. In an immediate-return environment, an animal can see the consequences of its behavior. It gets immediate feedback regarding whether it is accomplishing its essential life tasks.

Think of an animal foraging for food. If it finds food, it eats it and knows that it’s being successful at getting food. If it doesn’t find food, the animal knows that it hasn’t achieved the goal, so it keeps searching. In either case, it knows how things are going.

Ancient rock art painting depicting hunter-gatherers.
A hunter-gatherer rock painting in Chinhamapare Hill, within the Vumba Mountain Range in Manica, Mozambique. (Image: Ivan Learning Portfolio/Shutterstock)

Our prehistoric ancestors also lived in an immediate-return environment throughout most of human evolution. They’d wander around searching for food, dealing with threats that arose. On a moment-to-moment and day-to-day basis they received feedback about how they were doing in meeting their goals.

They didn’t have houses or permanent settlements or possessions. They weren’t trying to achieve anything for the future, so they had no uncertainty about how well they were doing. Of course, bad things could happen at any time, but they’d deal with those challenges as they arose, just as the animals in the wild do.

All of that changed with the agricultural revolution. After millions of years of living day-to-day in an immediate-return environment, about 10,000 years ago, people began to settle into permanent communities. They started to acquire land and possessions and grow their own food. And with the beginning of farming, they suddenly found themselves in what’s called a delayed-return environment.

Learn more about what makes people happy.

In a delayed-return environment, people invest a great deal of time and effort each day into tasks that don’t have any immediate rewards. People who rely on agriculture live in a delayed-return environment. They put a great deal of effort into planting and tending to their crops, with no assurance that the crops are going to grow. Hence, they worry about drought and pests, and about whether other people might come and steal their food.

Since agriculture allowed people to settle in communities, they started to build houses and barns and accumulate possessions. And then they started worrying about protecting their belongings and accumulating even more. So, instead of focusing only on how things were going on each particular day, people began to worry and experience stress about how things would turn out in the future.

Much of the stress of modern life comes from the fact that we live in a profoundly delayed-return environment. Some goals, such as our paycheck or an upcoming vacation, may lie just days or weeks ahead, but many others, such as a new house or an educational degree or retirement, could be many years away.

And as you put all of your time and effort into work or school today, you have no assurance that your hard work today will necessarily pay off. This uncertainty about the future is stressful.

Learn more about why do we have emotions.

Stressing About the Future

The third reason why people are so stressed out is that often there’s nothing we can do to solve the problems that worry us. In an immediate-return environment, most stressors are active. Hence, people can usually do something immediately that might deal with the acute stressor. Their actions may not be effective in dealing with the problem, and they might not survive, but at least they can usually take some action.

But when the things that create stress lie in the future, the threat resides more in our mind than being immediately present. It doesn’t mean the source of stress isn’t real, although sometimes it’s not. It means that the problem that’s creating stress isn’t ‘immediate.’ It’s not staring at us in the face. It’s something that we’re thinking about in our minds.

A young woman worried about something.
When the things that create stress lie in the future, the threat resides more in our mind than being immediately present. (Image: KieferPix/Shutterstock)

When a person lies awake at night worrying about something that might or might not happen days or weeks or years from now, there’s usually nothing one can do to solve that problem and eliminate the stress. Will I get a job after I graduate? Will I have enough money when I retire? Will my son or daughter solve his or her marital problems? Is my company going to downsize and lay me off?

These are all legitimate concerns, but they create chronic stress because there’s no way to take immediate action, particularly not at three in the morning. And those kinds of concerns are not likely to go away tomorrow or the next day or even next week. They’re chronic.

So the three main reasons why modern human beings experience chronic stress are that we live in an environment that is radically different from the one we evolved in, we face more uncertainty than ever before due to the delayed-return nature of our lives, and there’s often not much we can do to resolve the problems that stress us out because those problems lie in the future and are often beyond our control.

Common Questions About Reasons Behind Human Stress

Q: What are some stress factors?

The stress factors can be related to both internal and external factors. Internal factors are related to the thoughts and behavior of an individual, whereas external factors are related to the physical environment such as office, friends, and relations.

Q: What causes work stress?

Work stress is caused by work-related issues, such as heavy workload, job insecurity, and conflicts.

Q: What is the biggest cause of stress?

The biggest cause of stress, most of the time, is related to financial issues, which can manifest in various forms of other stresses.

Q: What is a stress response?

The stress response, or “fight or flight” response is the emergency response system of the body. This is taken in response to both acute and chronic stress.

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