You may not remember what you were doing a few minutes ago. But your dog probably does.
A study of 17 dogs found they could remember and imitate their owners' actions up to an hour later. The results, published Wednesday in Current Biology, suggest that dogs can remember and relive an experience much the way people do.
That's probably not a big surprise to people who own dogs, says Claudia Fugazza, an author of the study and an animal behavior researcher at Eotvos Lorand University in Budapest. Fugazza owns a Czechoslovakian Wolfdog named Velvet.
"Most dog owners at least suspected that dogs can remember events and past experiences," she says.
But demonstrating this ability has been tricky.
Fugazza and her colleagues thought they might be able to test dogs' memory of events using a training method she helped develop called "Do As I Do." It teaches dogs to observe an action performed by their owner, then imitate that action when they hear the command: "Do it."
"If you ask a dog to imitate an action that was demonstrated some time ago," Fugazza says, "then it is something like asking, 'Do you remember what your owner did?' "
In the study, a trained dog would first watch the owner perform some unfamiliar action. In one video the team made, a man strides over to an open umbrella on the floor and taps it with his hand as his dog watches.
Then the dog is led behind a partition that blocks a view of the umbrella. After a minute, the dog is led back out and lies on a mat. Finally, the owner issues the command to imitate: "Do it."
The dog responds by trotting over to the umbrella and tapping it with one paw.
In the study, dogs were consistently able to remember what their owners had done, sometimes up to an hour after the event.
The most likely explanation is that the dogs were doing something people do all the time, Fugazza says. They were remembering an event by mentally traveling back in time and reliving the experience.
Even so, the team stopped short of concluding that dogs have full-fledged episodic memory.
"Episodic memory is traditionally linked to self-awareness," Fugazza says, "and so far there is no evidence of self awareness in dogs and I think there is no method for testing it."
For a long time, scientists thought episodic memory was unique to people. But over the past decade or so, researchers have found evidence for episodic-like memory in a range of species, including birds, monkeys and rats.
Dogs have been a special challenge, though, says Victoria Templer, a behavioral neuroscientist at Providence College.
"They're so tuned into human cues, which can be a good thing," Templer says. "But it also can be a disadvantage and make it very difficult, because we might be cuing dogs when we're totally unaware of it."
The Budapest team did a good job ensuring that dogs were relying on their own memories without getting any unwitting guidance from their owners, says Templer, who wasn't involved in the study.
She says the finding should be useful to scientists who are trying to understand why episodic memory evolved in people. In other words, how has it helped us survive?
One possibility, Templer says, is that we evolved the ability to relive the past in order to imagine the future.
So when we're going to meet a new person, she says, we may use episodic memories of past encounters to predict how the next one might go.
"If I can imagine that I'm going to interact with some individual and that might be dangerous, I'm not going to want to interact with them," she says.
And that could help make sure the genes that allow episodic memories get passed along to the next generation.