Perhaps you and your dog have had a special moment. One where you both hugged and snuggled and you thought it was pretty special. For the moment it probably was. In fact for about two minutes. At least for your dog.
Researchers at Stockholm University and Brooklyn College found that for dogs, events are forgotten after about two minutes — and that's on the long end of the spectrum. Researchers did more than 90 memory experiments on 25 species that covered a variety of animals and even insects including birds, mammals, and bees.
On average the memory duration for all animals is probably similar to your teenager’s memory of when to be home or clean their room -- a mere 27 seconds. The chimp’s memory was even shorter -- 20 seconds. Rats even outdid them.
Humans, when compared in a similar study, had no problem remembering a sample stimulus they had seen as many as two days earlier. Which puts humans in the unique category in terms of remembering arbitrary events.
Reports from the University of Stockholm suggest that animals' memories can be broken into two categories — short-term and longer-term "specialized" memories. While animals can have excellent specialized memories such as where you keep the treats or where they hid their bone, or perhaps a bird who flies away from the nest but remembers how to return, memories of specific events tend to disappear in a span "ranging from a few seconds to several minutes.
The findings were published in December in Behavioral Processes, an academic journal.
Don't feel special
One researcher who did not participate in the study, however, cautioned that some animals have shown the ability to capture episodic memories the way humans can — great apes have been shown to do so for days, if not years — while another cautioned that "it might be too early to argue that humans are the only ones who are able to mentally travel back and forward in time." (Dolphins, meanwhile, can recall whistles 20 years later.) The dolphins' "social memory" is the longest ever recorded in the animal kingdom.
Then there are elephants, who really don't seem to forget much. In fact, their memories are key to their survival. Matriarch elephants, in particular, hold a store of social knowledge that their families can scarcely do without, according to research conducted on elephants at Amboseli National Park in Kenya. They can remember, for example, that there was a drought a year ago, enabling them to migrate to greener pastures to feed and protect their group.
So maybe it's good to know that when your dog jumps up and is happy to see you, it is you they are happy to see, not one specific event that they are recalling. They love you for you.