Think all bees look alike? Well we don't all look alike to them, according to a new study that shows honeybees, who have 0.01% of the neurons that humans do, can recognize and remember individual human faces.
For humans, identifying faces is critical to functioning in everyday life. When we look at another person's face, a special brain region, the fusiform gyrus, lights up (ScienceNOW 14 February, 2004). But can animals without such a specialized region also tell one face from another?
Knowing honeybees' unusual propensity for distinguishing between different flowers, visual scientist Adrian Dyer of Cambridge University in Cambridge, England, wondered whether that talent stretched to other contexts. So he and his colleagues pinned photographs of four different people's faces onto a board. By rewarding the bees with a sucrose solution, the team repeatedly coaxed the insects to buzz up to a target face, sometimes varying its location.
Even when the reward was taken away, the bees continued to approach the target face accurately up to 90% of the time, the team reports in the 2 December Journal of Experimental Biology. And in the bees' brains, the memories stuck: The insects could pick out the target face even two days after being trained. Dyer says the results challenge the idea that a specialized part of the brain is necessary to recognize a human face. "You see things in humans which you might attribute to having complex, mammalian brain, but until you go and test it in bees, you can't exclude the fact that a simple brain can do it."
It's a "neat study" that shows that bees are smarter than most people think, says cognitive neuroscientist Michael Tarr of Brown University in Providence, Rhode Island. But he believes the task the bees completed doesn't have much to do with how humans recognize each other's faces: "If they had used potatoes, I suspect they would have obtained the same result." Ethologist James Gould, who has done extensive research on how bees recognize flowers, agrees that humans have a specific evolutionary reason to be able to identify other people's faces, whereas for bees, it's just another shape and pattern. "For bees, faces are just a really strange looking flower," he says.