Buzzed Recall: Bumblebees Can Have False Memories Too

It’s the first time this phenomenon has been shown in a non-human animal. Nicole Milligan

Memory is notoriously faulty. Eyewitness testimony is increasingly viewed with skepticism, and teachers from kindergarten to graduate school can attest to the mutability of their students' recall. So-called false memories are common and widespread. Just ask Brian Williams.

Apparently this phenomenon isn't unique to humans. New research suggests that false memories also plague the bumblebee.

In a study published in the journal Current Biology, scientists showed that the insects can sometimes mix up the patterns of flowers, combining features from two different blooms in their memories.

"This is an exciting study [that] shows that a property of memory previously only ascribed to humans can in fact be found in an insect," says Gene Robinson, a researcher at the University of Illinois uninvolved in the paper. "The evolutionary distance between bees and people is so vast as to suggest that this might be a general feature of memory systems in some other animals as well."

The researchers first trained bees to visit artificial flowers with a black-and-white ringed pattern, by giving the insects a reward of sugary liquid similar to nectar. They quickly learned to visit only those flowers. Then the researchers changed it up and arranged it so the bumblebees only got rewards from artificial yellow flowers. The bees quickly adapted and only targeted these yellow ones, and not the black-and-white blooms, says study author Lars Chittka, a researcher at the Queen Mary University of London.

But when the bees were tested again one or three days later, many of the bees actually preferentially visited yellow flowers with black-and-white rings, a composite of the two blooms they'd been previously trained to prefer. It appears the bees had combined elements of each flower and formed a false memory, Chittka says. And this only happened after the bees had slept; before dozing, the bees only visited the yellow blooms, their most recent nectar sources.

The bumblebees didn't show a preference for other flowers with similar patterns but different colors, and vice versa, which were present in the "flight arena" where the testing took place, Chittka says. This shows that they were truly generating faulty remembrances.

"The study was performed meticulously, with many controls to help rule out some alternative explanations such as color biases or fatigue during the tests," Robinson says.

Chittka says he and his colleagues plan to further study these bees, which serve as a good model to help figure out how and why false memories form.