Your dog remembers more than you might think. A new study that tested the memory of man's best friend found that dogs exhibit something akin to episodic memory — a process that's been well documented in humans, but difficult to prove in other animals.
In experiments, the dogs were able to recall human actions even when they weren't expecting to be tested on what they observed, according to a report published Wednesday in the journal Current Biology.
The findings show that episodic memory, thought to be linked to self-awareness, may extend well beyond humans to species outside of the primate lineage.
Scientists have long wondered whether other animals have something like episodic memory, which allows us to recall specific past events even though they may not have been particularly important when they happened.
But this is not an easy question to answer. For starters, animals can't tell people exactly what they remember.
For this study, the researchers in Budapest, Hungary, trained 17 dogs to respond to a "do as I do" command. The human would perform an action — such as touching a chair or climbing on top of it — and then say, "Do it!" The dog would then imitate the human action, whatever it was.
This alone doesn't prove that episodic-like memory exists. To make that leap, the scientists had to show that the dogs remembered what they saw a person do even when they weren't expecting to be asked to imitate it.
So the scientists then trained the dogs to lie down after the human demonstrator performed an action, regardless of what that action was. After a while, the dogs were lying down consistently. Then, the humans surprised their canine companions with the "Do it!" command.
Keep in mind that the dogs had no reason to remember exactly what their human did, since they knew their job was to lie down regardless. Still, when tossed a "Do it!" command, they reliably imitated the human action. This was true one minute after the action, and still true an hour later (although their performance declined with time, which was to be expected).
Scientists can't say with certainty that the dogs were demonstrating episodic memory, and besides, definitions of "episodic-like" memory are not entirely agreed-upon. Still, the study does show that dogs can remember complex interactions with humans, even when they don't need to. This could offer researchers a new window into studying how episodic memory may work in other animals.
"This is the first evidence of episodic-like memory of others' actions in a non-human species, and it is the first report of this type of memory in dogs," the researchers wrote. Dogs could provide a useful window for studying animal memory, they added, especially since they evolved "to live in human social groups."
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