Some birds may use 'mental time travel,' study finds

Real quick — what did you have for lunch yesterday? Were you with anyone? Where were you? Can you picture the scene? The ability to remember things that happened to you in the past, especially to go back and recall little incidental details, is a hallmark of what psychologists call episodic memory — and new research indicates that it’s an ability humans may share with birds called Eurasian jays.

Real quick — what did you have for lunch yesterday? Were you with anyone? Where were you? Can you picture the scene? The ability to remember things that happened to you in the past, especially to go back and recall little incidental details, is a hallmark of what psychologists call episodic memory — and new research indicates that it’s an ability humans may share with birds called Eurasian jays.

With episodic memory, “you’re remembering an event or an episode, hence the name,” said James Davies, first author of the study that appeared May 15 in the journal PLOS One. “You kind of mentally relive it. It also involves other kinds of details that make up that experience, so sounds, sights, even your thoughts or your mood at the time.”

Episodic memory differs from semantic memory, which is the recall of factual information, added Davies, a doctoral student in psychology at the University of Cambridge’s Comparative Cognition Lab.

“It’s often helpful to think about episodic memory as remembering, whereas semantic memory is just knowing,” he said. “There’s not really a conscious recall involved.”

While episodic memory is integral to how most people experience the world, it can be difficult for scientists to prove whether nonhuman animals share this ability — after all, they can’t tell us what they’re thinking. However, for several decades, scientists have been devising experiments to delve into animals’ ability to remember previous events, and they have found evidence of episodic-like memory in creatures as varied as pigeons, dogs and cuttlefish.

Corvids — the group of birds that includes crows, ravens and jays — are famously smart, and previous studies have suggested that they are capable of episodic-like memory, which may help them find bits of food that they’ve hidden for later. In 1998, Dr. Nicola Clayton devised an experiment with scrub jays in which the birds appeared to remember what kinds of foods they’d hidden in different spots and how long ago.

This means of finding evidence of episodic-like recall — called a “what, when, where” protocol — has become standard among scientists studying animal memory. But Davies, who is Clayton’s advisee, wanted to find other ways to test for this cognitive capability.