Young Americans today are experiencing levels of , , , and related conditions at rates higher than they were a generation ago. (And the rest of us aren't doing much better.)

According to the federal Centers for Disease Control and Prevention, 1 in 10 Americans suffer from some form of depression, and people between the ages of 18 and 24 report the highest incidences.1,2 Forty million Americans over the age of 18 have an anxiety disorder, but again, as the recent report, "Stress in America," made clear, millennials are the hardest hit.3 More evidence: is the third-leading cause of death for young Americans between the ages of 10 and 24, claiming 4,600 lives per year. All of this, in a society that has more wealth than much of the rest of the world combined.

What's happening here?

Some claim it's simply fuller reporting—that we have better mental health resources in place than a generation ago, and more people are aware of their psychological problems than they once were. Others point to common sources of stress that have risen in recent years—money problems, unemployment and lack of job security, family instability, and increased personal responsibilities.

These may all be contributing factors, but there may be another, less-acknowledged piece of the puzzle driving our discontent.

And it's right in your pocket.

Comparing Monkeys

We humans love to compare ourselves to the people around us. Even when we are reasonably happy with we have, we become dissatisfied once we compare ourselves to someone who has something better. (You may have experienced a similar effect watching episodes of Keeping up with the Kardashians.)

This tendency appears to be innate in primates, and has been shown in animal models. In an enlightening and entertaining TED Talk, Frans de Waal reviews an experiment he conducted on capuchin monkeys to illustrate how they compare resource acquisition in much the same way humans do.

In the experiment, two monkeys in adjacent cages are rewarded for handing a researcher outside the cage a stone. The first monkey successfully gives the scientist a stone and is rewarded with a piece of cucumber. Monkey #1 is satisfied and enjoys his reward. Then Monkey #2 completes the same task, but is given a grape, which he eats with relish. Since monkeys like grapes a great deal more than cucumbers, things get interesting when they are tested again.

During the second round of tests, Monkey #1 once again successfully hands the researcher a stone and is given a cucumber. He puts the cucumber to his lips, looks at the researcher, then reaches outside the cage, throws the piece of cucumber at the scientist and shakes the cage. In the second round, Monkey #2 once again enjoys a grape.

As you might imagine, by the third round Monkey #1 appears positively outraged by the offer of a cucumber, shaking his cage, making noise, throwing cucumbers at the researchers, and so forth.

What was once fine—the cucumber—is now no longer even acceptable, in light of the possibility of enjoying a grape.

Data on income disparity among humans find similar results. The amount of money you make is not a good indicator of life satisfaction alone. Rather it's the rank of your income within a comparison group that seems to matter most.4 We see this quite clearly in communities where income disparity is highest. A measure sometimes called The Robin Hood Index plots household incomes in specific neighborhoods on a single graph. In places where the Robin Hood Index is highest, we see greater instances of violence and homicide.5 It's not just the amount of money people make, but income inequality that seems to drive these behaviors.

This kind of social comparison probably started as an adaptive behavior in animals as long as 540 million years ago. How do we know this? Our ability to compare is connected to the ability to choose between richer and leaner reinforcement schedules. If you couldn't do that, it would be disastrous from a survival standpoint. Animals have to be able to look around and see which field is more likely to yield good food. As socialization developed, this ability to compare stretched into the realm of community as well: If you look around and see another group or person is doing better than you, you may sidle up to the other group and make friends. If you've got a hunk of meat and I don't, I'm going to go over and stand next to you. Maybe you'll share, or I might even steal it from you.

Fast forward 540 million years and we have developed technological and cognitive abilities based on relational learning that put this process on steroids. We don't have to get angry over cucumbers; we can compare ourselves with little more than cognitive labels—who is hot, who is cool, or anything in between. We can be upset over what seems fair or unfair, based on complex ideas of "fairness." This process was known even in Biblical times, as the story of the workers in the vineyard illustrates (Matt 20: 1-16). But now science and technology—that mountain of achievement based on human —has given us the capacity to compare ourselves to anything or anybody, anywhere or anytime.

And that brings us back to your smart phone.

A Tool for Comparison

Right now, you have a device in your pocket or purse that allows you to carry out social comparisons like the ones described above constantly and with ease. It's your smart phone. With it, you can see what's going on anywhere in the world at any time.

Think about what this creates: No matter how successful you are, you are (probably) not a billionaire. But you can see how billionaires live with the push of a button. You can see how the rich and famous go about their daily lives, what they have that you don't, how they live that you can't.

The disparity is now transparent, and it pushes ancient psychological triggers we developed for important evolutionary reasons.

So how do we manage this? We aren't soon going to create a world that's good enough for everybody. That's not possible. Not everyone is going to become Bill Gates, but even if we could, it would never be enough. After all, most Americans are wealthy beyond imagination in comparison to much of the world's population, but we still have near-epidemic rates of anxiety, depression, and a host of other mental illnesses.

We're not going backwards. No one is going to smash their iPhones. What we have to do instead is create modern minds for the modern world. The question is: What does that mean and how do we do it?

In the modern world, we have to be Olympic-class psychological flexibility experts, just to get along. We have to teach and find a way to be more emotionally, cognitively, and behaviorally open and aware; we have to learn how to take the perspective of others; how to feel a little of what others feel; and how to stick with those feelings even when it gets rough. We need to create a more accepting, mindful, values-based, caring, compassionate world, and we have to start right here, right now in our families, schools, communities, culture, nation, and world.

The tools are out there. You can even find them on your smart phone.

References

1 http://www.cdc.gov/features/dsdepression/

2 http://www.cdc.gov/features/dsdepression/revised_table_estimates_for_depression_mmwr_erratum_feb-2011.pdf

3 https://www.apa.org/news/press/releases/stress/2012/generations.aspx

4 Boyce C, Brown , Moore, S. Money and happiness: Rank of income, not income, affects life satisfaction. Psychological Science. April 2010. 21(4): 471-475.

5 Daly, M and Wilson M. Homicide. 1988. Aldine Transaction Inc.