Ever wonder if your dog recalls those times you were were a really shitty owner? The latest science shows they most certainly do.
A new study published in Current Biology shows that dogs, like humans, can recall prior events, even when those events weren't particularly important or meaningful at the time. This suggests that dogs have "episodic memory", which is the ability to mentally travel back in time and recall experiences and specific events, such as times, places and associated emotions. Importantly, episodic memory is also a possible sign of self-awareness in dogs.
Photo: Peretz Partensky
That scientists needed to prove such a thing may come as a surprise to dog owners. Dogs often behave in a way that's suggestive of episodic memory, such as staying clear of the neighbour's cat after a particularly nasty encounter. Trouble is, we can't be entirely sure if dogs are actually reminiscing about a prior event, or if they're drawing on "semantic memory", which is the memory of facts and rules necessary for survival. We unfortunately can't ask dogs what's going on in their fuzzy little heads.
Evidence of episodic memory has been found in other species, including primates, rats and pigeons. However, these previous studies involved simple stimuli, such as the presence or absence of food, and were conducted in laboratory settings, which are a far cry from conditions found in real life.
To indicate the presence of episodic-like memory in dogs, Claudia Fugazza from the MTA-ELTE Comparative Ethology Research Group in Budapest, Hungary, used a trick called "Do as I Do" in which 17 dogs were trained to watch a person perform a specific action, and then perform the action themselves when given the command. For example, if the owner were to place their hand on an umbrella and then say "Do it!", the dog would also place its hand, er paw, on the umbrella. Other tasks involved standing on a table, sitting on a chair and jumping over obstacles.
"Do as I do!" For the training, dogs were trained to imitate human actions. But in some cases, they dogs didn't know they were supposed to remember certain actions, but they still remembered them anyway — a sign of episodic memory. (Image: Claudia Fugazza, Ákos Pogány and Ádám Miklós / Current Biology 2016)
On its own, this training wasn't enough to prove that dogs have episodic memory. The researchers needed to show that dogs were capable of recalling an event they weren't expecting to have to remember.
"The study of episodic-like memory in non-human animals is particularly challenging because it implies assessing a mental state: incidental encoding... of an event [that is, remembering stuff that doesn't seem to be important] when it is not known that it is important to remember it," Fugazza told Gizmodo. "Most scientists agree that incidental encoding can be assumed if the recall test is unexpected, because in this case the subject does not expect to be required to remember the event later, thus it does not know the event is important."
To create an unexpected recall test, the researchers added a second part to the "Do as I Do" exercise. The dogs were trained to lie down after watching a human perform an action, regardless of what it was. So if the owner stood on a table, the dog would lie down and be still. But sometimes, and in a sudden twist, the researchers would surprise the dogs by issuing the "Do it!" command. The dogs, after a slight pause, performed the action.
This means that the dogs remembered what the person did even though they had no particular reason to think they'd have to remember it. Importantly, the dogs had to remember events they had witnessed, but not performed before. This means they had to dig into the "recent history" file of their brains and pull out the required information — in other words, they had to rely on their episodic memory. The researchers applied this recall test to the dogs after one minute and one hour, showing that dogs are capable of remembering demonstrated actions after both short and long time intervals (though memory faded a bit over time).
"Our study is the first to test whether pet dogs in their own natural environment can remember complex and content-rich events that are close to real life situations," said Fugazza. "Moreover this is the first study to assess memory of actions performed by others, not by the subjects themselves." She believes this testing method can be used and adapted in a wide range of animal species, allowing scientists to better understand how animals' mind process their own actions as well as actions carried out by others.
As noted, episodic memory has been linked to self-awareness, which is the ability to see oneself as an entity that's separate and different from others. "So far no test has been successfully applied to study self-awareness in dogs," Fugazza told Gizmodo. "We believe that our study brought us one step closer to be able to address this question."