Our inability to perceive animal intelligence revealed the limits of our own. Via the Wall Street Journal, Frans de Waal writes:
Who is smarter: a person or an ape? Well, it depends on the task. Consider Ayumu, a young male chimpanzee at Kyoto University who, in a 2007 study, put human memory to shame. Trained on a touch screen, Ayumu could recall a random series of nine numbers, from 1 to 9, and tap them in the right order, even though the numbers had been displayed for just a fraction of a second and then replaced with white squares.
I tried the task myself and could not keep track of more than five numbers—and I was given much more time than the brainy ape. In the study, Ayumu outperformed a group of university students by a wide margin. The next year, he took on the British memory champion Ben Pridmore and emerged the “chimpion.”
A growing body of evidence shows, that we have grossly underestimated both the scope and the scale of animal intelligence. Can an octopus use tools? Do chimpanzees have a sense of fairness? Can birds guess what others know? Do rats feel empathy for their friends? Just a few decades ago we would have answered “no” to all such questions. No we’re not so sure.
Underlying many of our mistaken beliefs about animal intelligence is the problem of negative evidence. If I walk through a forest in Georgia, where I live, and fail to see or hear the pileated woodpecker, am I permitted to conclude that the bird is absent? Of course not. We know how easily these splendid woodpeckers hop around tree trunks to stay out of sight. All I can say is that I lack evidence.
It is quite puzzling, therefore, why the field of animal cognition has such a long history of claims about the absence of capacities based on just a few strolls through the forest. Such conclusions contradict the famous dictum of experimental psychology according to which “absence of evidence is not evidence of absence.”