Bumblebees Make False Memories, Too

People forget things every day, whether it's as simple as where we left our keys or the name of that new colleague at work. But we can also sometimes make false memories - a mistake that bumblebees also experience, according to a new study.

Previous research had credited errors in memory performance among non-human animals to simply failing to learn the task at hand, or learning it and then forgetting. But now, findings published in the journal Current Biology say bumblebees can reportedly "remember" things incorrectly, suggesting that this phenomenon is actually widespread across the entire animal kingdom.

"We discovered that the memory traces for two stimuli can merge, such that features acquired in distinct bouts of training are combined in the animal's mind," researcher Lars Chittka of Queen Mary University of London said in a press release. As a result, "stimuli that have actually never been viewed before, but are a combination of the features presented in training, are chosen during memory recall."

Bumblebees are actually rather clever insects, able to remember the patterns, colors and scents of various kinds of flowers. They can even find their way back home after covering long distances. But what if they accidentally remembered the wrong favorite flower or location?

To determine whether this was a possibility, Chittka and co-author Kathryn Hunt trained bumblebees to expect a reward when visiting a solid yellow artificial flower followed by one with black-and-white rings, or vice versa. Then they were presented with three types of flowers - including the two from before, plus one with yellow-and-white rings. Just minutes after the training, the bees still gravitated towards the most recently presented flower, remembering that it gave them a reward.

However, this accurate memory did not last. One or three days later, their memories were put to the test again. This time around, as the day wore on the bees got more and more confused. They would show the same preference as seen just minutes after training, but then later half of the time they started choosing the yellow and white flower - a flower never associated with a reward.

"There is no question that the ability to extract patterns and commonalities between different events in our environment [is] adaptive. Indeed, the ability to memorize the overarching principles of a number of different events might help us respond in new situations. But these abilities might come at the expense of remembering every detail correctly," Chittka explained.

Similar to humans, it seems bumblebees have a better short-term than long-term memory. With their limited brain capacity, researchers suggest, they are under pressure to make the most of the space they're given. That is, they store overarching features of a class of objects rather than each individual object, causing them to overlook the details.

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