Dogs may be capable of human-like emotions and consciousness, but their short-term memories are pretty terrible, particularly when the event in question is something relatively trivial and not survival-oriented.
A new study out of the Centre for the Study of Cultural Evolution in Stockholm, Sweden, found that in a survey of 25 types of animals, including dogs, the average short-term memory span was just 27 seconds. Canines fare slightly better than average, according to National Geographic:
Dogs forget an event within two minutes. Chimpanzees, at around 20 seconds, are worse than rats at remembering things, while the memory spans of three other primates — baboons, pig-tailed macaques, and squirrel monkeys — exceeded only bees (the sole study participant that wasn't either a mammal or a bird).
Nearly a hundred animals were observed using "a memory test of recent random events known as the delayed matching-to-sample (or DMTS) method":
An animal is typically shown a visual stimulus such as a red circle. The red circle disappears, then, after a delay, it's shown again with another sample stimulus — a blue square, say. The animal, usually with the incentive of a food reward, has to select the original sample it saw.
The results suggest that humans' capacity for "episodic memory" sets us apart from other animals:
While there are plenty of examples of animals with long memories — elephants never forgetting a face, the cat that's scared of the pet carrier after a past visit to the vet, swallows returning to last summer's nest — they aren't using episodic memory, according to [research team leader Johan] Lind.
Such cases "are due to associative memories," he says. They're not based on "memories of specific events. In the second case, the cat associates the carrier with danger. Such memories are very robust and will stay for a long time — for life — in animals."
That's because animals may have specialized memory systems hardwired to remember certain "biologically relevant information" (such as where to find food), the study authors proposed.
At last, an explanation as to why your dog freaks out every time the doorbell rings ("OMG WHAT IS HAPPENING?") but can also remember exactly which jacket pocket always contains his favorite bacon-flavored treats, or the fact that you putting on shoes and grabbing the leash means he's about to get to go outside.
Read the complete scientific paper in Animal Behaviour here.
Photo by Flickr user Kevin.