Pet owners might like to think they can judge the moods of their cats or dogs with ease, but finding true scientific methods to evaluate animal emotion is difficult.

In a review published in The Proceedings of the Royal Society B, researchers describe a framework that may help other scientists measure animal mood.

Image Credit... Chris Gash

Because it is difficult to otherwise judge an animal’s emotional state, the researchers devised a model that correlates emotional state to decision making. An animal that adopts a “safety first” stance to a rustle in the forest is probably feeling pessimistic, according to the framework. Conversely, an animal feeling optimistic would interpret the same rustle as a sign of prey.