In a series of experiments published in the Journal of Experimental Biology, Martin Giurfa from the Université de Toulouse, France, tested whether bees could distinguish random arrangements of dots and dashes from arrangements in which two dots were positioned like eyes, and dashes or dots represented noses and mouths. The bees were rewarded with sugar snacks when they chose the correct answer. It turns out that the bees could distinguish between the patterns. Once the bees had learned that the face-like patterns of dots and dashes yielded the rewards, they could correctly identify similar face-like patterns that they had not specifically seen.
The bees’ talents go well past dots and dashes, however, as was shown by the next set of experiments. This time, the researchers used actual photographs of humans. The bees were trained to go to one or the other of a pair of similar male faces. Bees were close to 80% successful in distinguishing the two faces. The scientists then doctored the faces to remove either external features (hair and ears) or internal features (eyes, nose, mouth). The bees still scored over 60% in choosing the correct face. Surprisingly, they did better without the internal features than without the hair and ears. When the pictures were vertically scrambled (eyes on the bottom, forehead in the middle), the bees scored no better than chance.
Apparently, bees not only can distinguish face-like conformations of dots and dashes from randomly assorted dots and dashes, they can also differentiate between pictures of real human faces. Truly amazing when you consider the bee brain is only about one cubic millimeter in size.