Life can be unfair sometimes, where it can seem like someone is always two steps ahead of you. For this reason, humans and other primates evolved to support long-term cooperation, according to new research.

"Giving up an outcome that benefits you in order to gain long-term benefits from the relationship requires not only an ability to think about the future, but also the self-control to turn down a reward," Dr. Sarah Brosnan of Georgia State University explained in a statement. "These both require a lot of cognitive control. Therefore, we hypothesize that lots of species respond negatively to getting less than a partner, which is the first step in the evolution of fairness, but only a few species are able to make the leap to this second step, which leads to a true sense of fairness."

Making the conscious decision to remain equals with someone rather than opt for immediate gratification is a behavior that, so far, has only been established in humans and apes, according to researchers.

The findings were published in the journals Science and Nature.

But given that fairness is a social ideal, how can you measure it? Well, to understand how this behavior evolves in humans, Brosnan and her colleagues spent the last 10 years studying behavioral responses to equal versus unequal reward division in other primates. Fairness is central to humans, but the researchers hypothesized that it evolved, and therefore elements of it can be seen in other species.

"This sense of fairness is the basis of lots of things in human society, from wage discrimination to international politics," Brosnan said. "What we're interested in is why humans aren't happy with what we have, even if it's good enough, if someone else has more.

In the study, the researchers tested the theory on brown capuchin monkeys, who would become agitated and refuse to perform a task when a partner received a superior reward for that same task. Since then, the response has been tested in nine different primate species - including humans - and Brosnan has found that species only respond to inequity when they routinely cooperate with those who are not related to them.

So the next time you find yourself in an unfair situation, just remember to hang in their because odds are it will pay off in the long run.