At school in the 1950s, we were taught that only humans were capable of using tools writes Richard Collins.
To think that other creatures could do so was heresy; traditionalists wanted to put clear water between the ‘brute beasts’ and ourselves. Animals, they conceded, had souls but, unlike our immortal ones, theirs did not survive death.
In The Descent of Man, Darwin referred to monkeys using tools. Nobody believed him until film footage appeared showing chimps breaking open the hard shells of nuts with stones. In due course, other primates gained admission to the tool-using club. Then the extraordinary cognitive abilities of dolphins were revealed.
Elephants also use tools. Recently, the crows demonstrated problem-solving skills equal to those of the great apes. But how far ‘down’ the chain of the animal hierarchy does tool-using, and the rationality implicit in it, go?
Insects and spiders, with tiny brains, seemed able to perform only pre-programmed tasks. Spiders construct their extraordinary webs automatically, like robots in a car-assembly plant. Tiny creatures, it was thought, couldn’t manipulate objects with a goal in mind, but now researchers at Queen Mary University London are challenging that assumption. They showed, last year, that bumblebees can be trained to pull strings for sugary rewards. Now the bees have been put through their problem-solving paces. A ground-breaking experiment is described in the February edition of Science.
A bumblebee in the wild visits thousands of flowers of many species, encountering a unique situation on each occasion. Pulling strings is not that different from some of the actions a bee might have to perform when foraging. To test bee ingenuity, the researchers needed to create situations unlike any that would be faced in the wild.
The insects in the Queen Mary experiment were shown a model bumblebee, attached to a stick, moving a ball in a mini arena. When the fake bee pushed or pulled a ball to a spot in the centre of the space, it received a reward. All of the watching bees soon learned to repeat the procedure. Bees may move objects about when nesting, but rolling balls around an arena is not a skill they would need in the wild; doing so in this experiment was an entirely novel experience for them, a real test of ingenuity and tool-use.
Some bees moved balls to the designated area without being trained. Others had to be shown how to do so, using the fake bees manipulated by researchers or balls being moved by magnets under the table. Those seeing the balls pushed by sticks learned the task more quickly than those seeing balls moved in ‘ghostly’ fashion by magnets. A third group learned the skill by watching trained bees move the balls and copying them. The members of this group learned most quickly and went on to be the best performers.
But the bees did not simply reproduce the observed behaviour; they improvised. Some developed their own individual methods of accomplishing the task. In a refinement of the experiment, researchers positioned balls close to, and further away from, the reward location. Researchers then showed them the far-away ball being moved to the centre. Given the choice, would the bees copy what they had just been shown and move the remotely located ball, or would they go for the one closest to the target? They chose the closer ball. Bees could also select a ball of a particular colour to secure the reward.
The ‘cognitive flexibility’ the insects demonstrated impressed the researchers. Bumblebees, they conclude, have the ability to solve complex problems if environmental pressure requires them to do so. Brainy bees are not just mindless robots after all. We have no choice but to admit them to our exclusive rationality club. Is nothing sacred?
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