Many people believe that they have seen evidence that chimpanzees can readily retrieve a banana hanging from a high point when provided with a few boxes which can be stacked to enable the chimp to climb up and reach the reward. Indeed, they may even be able to recall a famous photograph taken by Wolfgang Köhler in 1927 which definitely seems to illustrate this—along with another chimpanzee evidently thoughtfully standing by and watching (presumably ready to do the same if given the chance).
I for one certainly believed this, but when I thought about it more I noticed one or two odd things. First, I thought, if chimpanzees can do this so easily, why haven’t I seen film footage of chimpanzees doing it more recently? And again, why can I only recall ever having seen the one, single photo? Surely, if chimpanzees can solve the box-building problem so readily, the experiment must have been repeated numerous times and surely would be on every TV documentary about chimps!
The answer is that chimpanzees have no insight into the physical principles governing box-stacking whatsoever. On the contrary, Köhler reported that the chimpanzee “solves not by insight, but by trying around blindly.” In short, the box-building-to-retrieve-the-banana was a one-off fluke and is nothing like the clear-cut case of chimpanzee “insight” that it is usually taken to be. Consequently, films of chimps trying to solve the problem—rather than single photographs—would reveal the truth all too clearly, explaining why they are never seen.
But fortunately we no longer have to rely on such dated and anecdotic material. Much more recently, Daniel Povinelli and his colleagues have carried out a meticulous series of experiments ranging over many years and with many different chimpanzees designed to test the claims that these animals think like we do when using tools. What is outstanding about this work is the great care that was taken to design experiments which could unequivocally demonstrate thought as opposed to mere behaviour, or insight rather than conditioning. Povinelli’s wonderfully ingenious experiments prove that chimps are nowhere near 95 per cent human. On the contrary, the evidence suggests that our closest primate cousins have not evolved either what I would call mentalistic or mechanistic cognition—underlining the point that these are indeed the cognitive adaptations which are truly distinctive of our species.
More recently, the English science writer Jeremy Taylor has published Not A Chimp. Taylor focuses on the alleged close genetic similarity between humans and chimps and has a field-day disposing of the nonsense which claims that chimps are approximately 95 per cent human and humans just about 5 per cent shy of being chimps. Where DNA is concerned, the reason is simple: genes are not plans or blueprints, they are more like recipes. Consider a 20-instruction recipe for making a cake that substituted cement for flour or 20 hours cooking for 2. The recipe would only be 5 per cent different (1 item in 20), but would the resulting cake in either case be 95 per cent the same as the original?
Taylor’s book is a superb account of recent advances in genetics which have refuted once and for all the belief that humans have hardly evolved since we parted company with the common ancestor of ourselves and modern chimpanzees. And like Povinelli, Taylor reveals the fallacy in believing that similar behaviour to our own on the part of chimps necessarily means similar mentality. On the contrary, he shows that bird-brained crows and domesticated dogs can be markedly better than chimpanzees in some skills while being genetically much more remote from us. To put it another way, you could say that both Povinelli and Taylor reveal the extent to which human beings can all too easily project their own mentality onto other species: something I would call hyper-mentalizing and something that I would also claim is the core and essence of insanity. And let’s be honest about it: claiming human rights for chimps—or even 95 per cent rights—as some have indeed claimed is insane. Those in question—prominent politicians, primatologists, and philosophers are prime examples of hyper-mentalism and strikingly illustrate the worry about such people that I raised in a previous blog.