Using data from 23 studies of what psychologists call 'inequity aversion,' researchers combed through results of more than 60,000 observations involving 18 animal species. In what they said was the ...

Many of us as dog parents have experienced the quirks of a jealous dog. Sometimes their behavior is endearing—a sweet reminder of just how deeply they cherish your attention and presence. But that's ...

Jealous pups pull out all the stops when one sibling gets extra love, resulting in playful antics.

It’s a question that has puzzled thinkers for centuries: Are we humans alone in our pursuit of fairness and the frustration we feel when others get what we want? In recent years, evolutionary ...