Alex's Adventures in Numberland - Alex Bellos [9]
In the first session Ai placed 0 between 6 and 7. Matsuzawa calculated this by averaging out which numbers she thought 0 came after and which numbers she thought it came before. In subsequent sessions Ai’s positioning of 0 went under 6, then under 5, 4 and after a few hundred trials 0 was down to around 1. She remained confused, however, if 0 was more or less than 1. Even though Ai had learned to manipulate numbers perfectly well, she lacked the depth of human numerical understanding.
A habit she did learn, however, was showmanship. She is now a total pro, tending to perform better at her computer tasks in front of visitors, especially camera crews.
Investigating animals’ mastery of numbers is an active academic pursuit. Experiments have revealed an unexpected capacity for ‘quantity discrimination’ in animals as varied as salamanders, rats and dolphins. Even though horses may still be incapable of calculating square roots, scientists now believe that the numerical capacities of animals are much more sophisticated than previously thought. All creatures seem to be born with brains that have a predisposition for maths.
After all, numerical competence is crucial to survival in the wild. A chimpanzee is less likely to go hungry if he can look up a tree and quantify the amount of ripe fruit he will have for his lunch. Karen McComb at the University of Sussex monitored a pride of lions in the Serengeti in order to show that lions use a sense of number when deciding whether to attack other lions. In one experiment a solitary lioness was walking back to the pride at dusk. McComb had installed a loudspeaker hidden in the bushes and played a recording of a single roar. The lioness heard it and continued walking home. In a second experiment five lionesses were together. McComb played the roars of three lionesses through her hidden loudspeaker. The group of five heard the roars of three and peered in the direction of the noise. One lioness started to roar and soon all five were charging into the bushes to attack.
McComb’s conclusion was that the lionesses were comparing quantities in their heads. One vs one meant it was too risky to attack, but with five-to-three advantage, the attack was on.
Not all animal number research is as glamorous as camping in the Serengeti or bonding with a celebrity chimpanzee. At the University of Ulm, in Germany, academics put some Saharan desert ants at the end of a tunnel and sent them down it foragng for food. Once they reached the food, however, some of the ants had the bottom of their legs clipped off and other ants were given stilts made from pig bristles. (Apparently this is not as cruel as it sounds, since the legs of desert ants are routinely frazzled off in the Saharan sun.) The ants with shorter legs undershot the journey home, while the ones with longer legs overshot it, suggesting that instead of using their eyes, the ants judged distance with an internal pedometer. Ants’ great skill in wandering for hours and then always navigating their way back to the nest may just be due to a proficiency at counting strides.
Research into the numerical competence of animals has taken some unexpected turns. Chimpanzees may have limits to their mathematical proficiency, yet, while studying this, Matsuzawa discovered that they have other cognitive abilities that are vastly superior to ours.
In 2000 Ai gave birth to a son, Ayumu. On the day I visited the Primate Research Institute, Ayumu was in class right next to his mum. He is smaller, with pinker skin on his face and hands and blacker hair. Ayumu was sitting in front of his own computer, tapping away at the screen when numbers flashed up and avidly scoffing the apple cubes when he won them. He is a self-confident lad, living up to his privileged