Have you ever had this experience? Today is the day you’re going to take your dog to the vet, something that she hates. The appointment isn’t for a few more hours, but you realize that she’s already hiding from you and when you grab her leash and get ready to go, it’s clear that she knows what’s going to happen and is doing everything to avoid it, almost as if she has dog ESP.
How did your dog know that?
Logically, she should have no idea that a trip to the vet is in store. She should only think that it’s time to go for a walk or a ride and get excited. But something is different in this scenario, and that something is what your dog remembers.
Whether you know it or not, your behavior is different on “vet day” as well, and your dog has learned to read the clues. You’ve been spending the entire day telling her, “We’re going to the vet today!” without realizing it. So how does your dog do it?
Before we get to that, we need to understand a little bit about how memory works.
Different kinds of human memory
Ignoring differences between short- and long-term memory and conscious and unconscious memory, humans have three different kinds of memories. Procedural memory is unconscious and is concerned with learned skills and is sometimes called muscle or motor memory. When a dancer performs a routine, a musician plays their instrument, or an athlete performs, that is procedural memory in action. There’s absolutely no question that humans and animals share this ability, and your dog demonstrates it every time you throw a ball and he catches it mid-air.
Next is semantic memory, which is the memory of real-world facts and data. When you remember your phone number, your SO’s birthday, or a friend’s address, that a semantic memory. For dogs, this involves things like the proper interpretation of commands — “If I do this when I hear that command, I may get a reward.” Again, there’s no question that dogs share this kind of memory with humans because it’s so easy to measure.
The third type is called episodic memory, and this is the one that was believed for years to be a solely human trait. These memories are more complicated and detailed and relate directly to events that happened in the past. Remembering a conversation you had on a first date, or your feelings at a concert, or the excitement of riding a rollercoaster are all episodic memories.
Previous thinking on dog memory
The reason that researchers believed for years that animals could not form episodic memories is because there was no way to test them linguistically. That is, they couldn’t just ask a dog, “What do you remember?” That statement now may appear obviously specist, but that was the attitude at least from the 1980s.
However, that began to change when a 2006 study at University of Edinburgh showed that hummingbirds could remember the what, where and when necessary to correctly locate an artificial flower that contained a reward based on its color, location, and time of day — all key elements of episodic memory. Of course, we also know now that many animals, like birds and dolphins, may use language to communicate, so perhaps it shouldn’t be a surprise.
As far as we know, though, dogs do not use language in the same way, although they can learn several hundred human words, which would seem to eliminate any chance that they form episodic memories. However, new research may have shown that dogs do form memories in this way.
“Do as I do…”
In order to test whether dogs do have episodic memory, researchers had to come up with a test through which a dog could “tell” them that it remembered something specifically in the past that was not associated with a specific spoken command, which would be an example of semantic memory.
They began by teaching dogs to “do as I do.” That is, if a human touched an object, then the dog would copy them and touch the object. If the human jumps, then the dog jumps. The command they were taught to repeat the action was “Do it.”
Next, the dogs were trained to lie down after seeing the human perform an action, no matter what that action was. Once the dogs responded automatically by lying down in association with the action, experimenters began to give the “Do it” command instead, and unexpectedly. They also tested the dogs’ memories by delaying giving this command after the action at an interval of one minute and one hour. They concluded that, “The results show they were able to recall the demonstrated actions after both short and long time intervals. However, their memory faded somewhat over time.”
What it all means
Since it’s been several hundred million years since humans and dogs have shared a common ancestor, finding evidence of episodic memory in both indicates that it may be common in many mammals. Why is this important? Because it reminds us once again that many animals are a lot more complex, mentally and emotionally, than we have assumed in the past.
Yes, they don’t have a lot of our mental skills when it comes to thinking, planning ahead, making art, or appreciating a sunset — but they still have complex inner lives and, while they may not experience memory exactly the same way that we do, they are capable of forming memories the same way.
One question to ask ourselves is what effect we are having on this ability of dogs now after they have spent tens of thousands of years co-evolving with us even as we have modified them through selective breeding. Is it possible that we are actually increasing the ability of dogs to experience episodic memory?
That’s a question for another scientific study, but keep this in mind. Science has already shown that there’s one really incredible way that humans can keep their own episodic memory skills as they age: become bilingual. In essence, we have already taught dogs to understand a second language — ours. Maybe that’s why they seem to be so good at the episodic memory game as well.
But the next time your dog figures out it’s time to go to the vet long before you say the words, remember that it’s just one more example of how good they have become at figuring us out and knowing what we’re going to do before we do it, and they have their episodic memory to thank for that.