The evolutionary history of minds

Two years ago, responding to a post by John Hawks on unique evolutionary events and their relationship to the Drake Equation, I praised Stephen Baxter's 2004 book Evolution. The book never got the fame I thought it deserved, but I'm pleased to see it's still in print.

Baxter does a fantastic job imaging a language and tool using velociraptor-like animal in, I think, the late Cretaceous. Alas, these obligatory carnivores wipe out their primary food supplies -- an ominous precedent for later chapters.

Ever since Baxter I've wondered how many sentient species have preceded us. Certainly there are several alive today, perhaps including canids. How many were rich language users? Ahh, that's harder. We, by which I include our Neandertal brethren, are the only rich language users we know of. How many technocentric species? Again, we know of only one; if there'd been anything like us before we'd have found their signature in the ice cores.

So we do seem somewhat unique, though it's puzzling that we should be. Why not others in the eons of evolution before us?

It's a great puzzle, and Scientific American addresses it as a part of their homage to Darwin series ...

One World, Many Minds: Intelligence in the Animal Kingdom: Scientific American:

.... Beginning in the 1980s, the field of comparative neuroanatomy experienced a renaissance. In the intervening decades evolutionary biologists had learned a great deal about vertebrate evolutionary history, and they developed new and effective methods of applying Darwin’s concept of the tree of life to analyze and interpret their findings. It is now apparent that a simple linear hierarchy cannot adequately account for the evolution of brains or of intelligence. The oldest known multicellular animal fossils are about 700 million years old. By the Cambrian period, about 520 million years ago, the animal kingdom had branched into about 35 major groups, or phyla, each with its own distinctive body plan. As a separate branch of the tree of life, each lineage continued to evolve and diversify independently of the others. Complex brains evolved independently in multiple phyla, notably among the cephalopod mollusks of the phylum Mollusca and, of course, among various groups of vertebrates. Vertebrate evolution has likewise involved repeated branching, with complex brains evolving from simpler brains independently along numerous branches....

It's a long essay, but worth reading. See also a 2004 post on the rapid and ongoing changes to the human mind and brain. I particularly appreciate the cephalopod reference -- Sentient squids are a favorite topic of science fiction of course ...