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Bees brighter than we knew, study finds They pass cognitive tests usually given apes, people Keay Davidson, Chronicle Science Writer |
Thursday, April 19, 2001
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Bees are famously busy -- but they're also pretty brainy. Our pollen-hunting friends possess "higher cognitive functions," judging by cunning experiments in which the creatures learned to compare and distinguish different colors and patterns, according to today's issue of Nature. In what an outside expert praises as "an exciting discovery," the French researcher Martin Giurfa and four colleagues showed that honeybees -- that's Apis mellifera to bee fanciers -- excel at cognitive tests normally performed by lab primates and human volunteers. In the current film "O Brother, Where Art Thou?" George Clooney announces to his little band of waifs that he should lead them because "I'm the one with the capability for abstract thought." As the Nature article shows, bees also can engage in abstract thought. The creatures can "master abstract inter-relationships," specifically the cognitive concepts of "sameness" and "difference," Giurfa and his team report. Hence, "higher cognitive functions are not a privilege of vertebrates," that is, creatures with backbones and much more complex nervous systems. To demonstrate this, Giurfa and his team exposed bees to a simple Y-shaped maze. The entrance to the maze was marked with a particular symbol -- say, the color yellow. A bee flying through the entrance encountered a branching pathway. One branch was marked with the color yellow, another with the color blue. Bees that pursued the yellow-marked path discovered at its end a vial rich in sugar. Bees that took the blue path got no sugar. Normally, bees would have been just as likely to fly one way as another. But via Giurfa's experiment, the bees learned that sugar lay at the end of the route marked with the same symbol as that marking the outside entrance. In other words, "same" equals "sugar." The bees demonstrated an ability to recognize "sameness" and "difference" -- fundamental skills on any test of cognitive abilities. In a second experiment, the bees showed they could apply the concepts of "sameness" and "difference" beyond what they had learned in the first experiment. In subsequent experiments, the opening to the maze was marked by a different symbol -- such as vertical dark lines. In that case, on entering the maze the bees re-encountered the two pathways, which this time were marked not with colors but, rather, with lines -- vertical lines on one path, horizontal lines on the other. Had the bees remembered the lesson of the first experiment, namely that "same" equals "sugar"? They had. In the second experiment, more than 70 percent of the bees promptly flew down the path marked by vertical dark lines, the same symbol as that above the entrance. Judging by the experiments, bees' capacity for abstract thought is so impressive that Giurfa, who works at both Laboratoire d'Ethologie et Cognition Animale in Toulouse, France, and Institut fur Biologie in Berlin, bristled when a Chronicle reporter characterized bee cognition as "low-degree." "I disagree with your characterization of this being a 'low-degree' of intelligence," Giurfa replied by e-mail. "In fact, it would be the opposite! "(In the past) many researchers thought that this kind of learning -- learning of an abstract rule, which is independent of the stimuli used -- can only be possible in primates and human beings. Here (in this experiment) we show that this is not true. Abstract rules can also be mastered by the mini brain of a honeybee." "It is an exciting discovery," said a leading bee authority, Professor Michael S. Engel, curator of the division of entomology at the University of Kansas. "Early in the last century, (zoologist Karl) von Frisch shattered our concept of insect cognitive capacities by demonstrating that honeybees communicated by an abstract language -- that is, via the famous 'waggle dance. ' This eventually won him the Nobel Prize. "The findings by Giurfa and colleagues further reveal the cognitive level of bees and at the same time suggest that seemingly complex behaviors may have a relatively simplistic neural (nervous system) architecture," Engel added. In other words, if bees -- with their relatively simple nervous systems -- can be so smart, then human intelligence might eventually be explained more easily than previously assumed. E-mail Keay Davidson at kdavidson@sfchronicle.com. |
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