Can brain waves tell us how animals feel?

A recent study found horses in fields exhibit different brain waves than those in stables. Credit: Rob Mitchell

Biologists spend a lot of time figuring out how animals behave. Can they also figure out how they feel?

Researchers have deployed a mobile headband to detect brain waves in horses — a device that could also be used for other species. In humans, electroencephalograms have been used to detect signs of depression and anxiety. Scientists wondered if they might detect similar feelings in animals.

“EEG studies in rodents, farm animals, and pets … have revealed how they react to being touched by a human or undergoing anesthesia,” writes Science. “But so far, no one had found a way to record brain waves in animals while they move around.”

Researchers at the University of Rennes, in France, did. In a study published in Applied Animal Behaviour Science, they found differences in the brain waves of horses in stables versus those in fields. In humans, those differences could point to anxiety and depression in stabled horses and calmness in those outside.

Some biologists urge caution, however, saying that brain wave interpretations may not be the same for humans and animals.

Read more in Science.