There is, to put it mildly, a lively debate among psychologists about just what human intelligence is. It is not that we haven’t measured it. For almost a century, scientists have been collecting data on millions of people around the world. What we don’t agree about is what we are measuring. Is intelligence the same thing in everybody? Is intelligence measurable with the fine-tuned calibration test results would suggest, or are the numbers a great conceit? Or something in between?
A similar debate is taking place about the intelligence of non-human primates. Professor Vernon Reynolds of Oxford University believes that chimps are smarter than orang-utans. Whether you agree with him or not, or whether you think primates can be ranked in an IQ league table suggested by James Lee (see in this blog Apr. 23: The Surprising Intelligence of Non-Human Primates) depends on what you think intelligence is.
Orang-utans are less boisterous than chimps and are better at solving problems requiring persistence and patience. They can pick a padlock and make stone tools. Given the opportunity, they will even do the washing up. There are chimps, on the other hand, who can speak using American sign language, and their mathematical achievements are impressive.
Perhaps the difference in the intelligence of chimps and orang-utans is different for the same reasons that it varies among humans. Our capacities for intelligent behaviors depends not only on our brains but on our temperaments, our opportunities, on what we want to do, and what we’ve been taught to do.