Are you one of those jealous people constantly comparing your life to that of Kim Kardashian or your friend with the great vacation pictures on Facebook? Good news: you don’t need to envy about one-third of the population, because they’re wasting their time being envious, too.

A new study out of Spain, published Thursday in Science Advances, suggests that “envious” is the most common personality type. A computer algorithm classified people based on their behavior in hundreds of social dilemma scenarios and found the majority could be categorized into four basic personality types: optimistic, pessimistic, trustful and envious. Thirty percent of the people were rated as envious.

“These subjects seem to behave as driven by envy, status-seeking consideration, or lack of trust,” the researchers wrote in their paper. “These players prevent their counterparts from receiving more payoff than themselves even when, by doing so, they diminish their own potential payoff.”

Each of the other three personality types ― pessimistic, optimistic and trustful ― described about 20 percent of people. The last 10 percent behaved so erratically that the computer program failed to categorize them.

These types are very different from the dimensions of personality we more often hear about ― mainly the Big Five of extraversion, agreeableness, conscientiousness, neuroticism and openness. Those five try to describe aspects of an individual’s general psychology. The four new categories, in contrast, describe the types of behaviors that people show in a social context, where they have to interact with others.

The new study analyzed the responses of more than 500 volunteers to hundreds of hypothetical dilemmas in which people could either cooperate with their teammate or act in their own self-interest. In one scenario, for example, two people are going hunting. On their own they can catch rabbits. If they cooperate, they can take down a deer, which means a bigger prize for both. But if one opts for rabbits and the other for deer, the lone deer hunter is out of luck. And the players don’t know what their teammate is thinking.

So what would you do in that situation ― settle for rabbits, or take your chances and go for the deer?

This thought problem and others used in the study are variations of the well-known prisoner’s dilemma, in which the two players are facing jail time. They are told that if both of them remain silent, both will be freed due to lack of evidence. If only one of them confesses, essentially betraying the partner, the confessor will be freed but the other will go to jail. If both confess, both will go to jail but with a shorter sentence. And they can’t consult each other.

For each individual, the safer option, and hence the more rational choice, is to confess and end up either free or jailed with a shorter sentence. But many times people opt to cooperate with their partner in crime and keep silent, even though they have absolutely no guarantee that their partner will do the same.

The prisoner’s dilemma is often used to show that people are not always rational beings focused on their own interest. They may cooperate with each other because they have a sense of the greater good (in this case, the good of the team) or because they have faith in the kindness of others or simply because they are nice.

But as these new findings show, it’s not just rationality or cooperative spirit that determines what humans end up doing. Their own personalities, too, play a part.

In the deer vs. rabbit scenario, for example, envious people chose to hunt rabbits because they wanted to get a deal at least equal to their partner’s. The optimists chose to hunt deer, hoping for the best. The pessimists went for rabbits, demonstrating their extreme aversion to risk. The trustfuls chose hunting deer too, without hesitation. (The trustfuls differed from the optimists in that the former chose cooperation in every round of these dilemmas without actually caring about winning or losing. They were probably the wisest, really.)

“The results go against certain theories; the one which states that humans act purely rationally for example,” study co-author Yamir Moreno of the University of Zaragoza in Spain said in a press release.

The envious 30 percent failed to cooperate just because they couldn’t stand the thought of potentially being left with a lower payoff than their teammate received. “This points to the difficulty of making people understand when they face a nondilemmatic, win-win situation,” the researchers wrote.

Although the games in the study offer hypothetical scenarios, they resemble many real-life interactions. Imagine that you are partnered with a co-worker on a special project. To achieve spectacular results, you both need to work hard. But it’s not guaranteed that the two of you will be given equal credit for the success of the project. So you might choose to do just the minimum, which certainly prevents your partner from getting unearned praise, but also deprives you of the credit that could come with the best results.

This approach is apparently satisfying to the envious. Who may constitute almost one-third of society. How frightening.