How Animals Manage their Feats of Engineering

In the TLS, James Gould reviews Mike Hansell’s Built by Animals:

Hansell’s primary target is cognitive ethology, and in particular the late Donald Griffin. He takes umbrage at the title of an uncited article: “Thinking about thinking”. Even as loosely defined as Griffin had in mind, apparently “thought” should be a forbidden term. Hansell’s strategy for arguing that animals are intellectually dead is three-pronged. The first step is to discount the abilities of animals on the basis of brain volume. The second is to invoke Occam’s razor (the simplest possible explanation is likely to be – or for some, is inevitably – the correct one). The last step is to describe animals that fit the mindless-builder model.

Brain size, Hansell tells us, should lead “to certain expectations” – namely, that smaller animals are simple and have limited, stereotyped repertoires. Using this simple rule of thumb, we can apparently conclude thats ince female humans have, on average, significantly smaller brain volumes than males, their behaviour should be simpler and more stereotyped – one of Darwin’s few mistaken inferences. Humans, by the same token, should be less behaviourally elaborate than whales and elephants. In fact, it is relative brain volume that seems to matter. When researchers plot brain mass against weight for warm-blooded animals, the points cluster rather tightly around an upward-slanting line. On average, an animal weighing ten times as much has a brain about five times as heavy. All other things being equal, brain mass scales with the number of sensory receptors and muscles the animal possesses, and these increase more slowly than weight. (Cold-blooded animals generate a line of the precisely same slope, though they are able to make do with one-tenth the number of neurones. Insects, because so much of their nervous system is in ganglia outside the head, fall on a different line.)