Last week I posted a segment on the lack of imagination in science fiction today, with a view toward how so many sci-fi characters are humanoid in appearance. Now I want to take a short look at what I’m talking about when I say “humanoid.”
In the evolution of animals over the past two billion years or so, there’s been a tendency for the sensory organs to become concentrated in the head. This is true for all the higher animals—and by that I mean basically those with a backbone and a large nerve cord running down the back—but it’s also true for some lower animals, such as insects and other arthropods. This is called cephalization, and it’s what is so often copied by us sci-fi writers when we devise characters to populate planets far, far away. This process has put four of the five traditional senses in the head: sight, hearing, smell, and taste. (The sense of feel, of course, is present throughout the body, we don’t have just one organ for that.) Why this should have happened evolutionarily, I’m not sure, but it may have to do with keeping the nerve fibers that run from the sense organs to the brain as short as possible. That may, in turn, have been to allow the information collected by those organs to be processed as rapidly as possible. If our eyes were in our kneecaps, for example, the nerve fibers would have to run all the way up the body to the head. Might be some loss of information in that long a trip. Secondarily, in a long, slender animal, such as a fish or a cougar, having the sensory organs up front could allow the animal to detect things ahead—food, danger, a mate, whatever—as immediately as possible, and shorten the reaction time to whatever’s out there. Always a good idea.
But for whatever reason, this is how humans are constructed. And so are many of the characters in science fiction. The Roswell “little green men” are shown this way, and this is the most likely reason they’re not real. Any time I see a purported visitor from outer space that looks like it’s been based on humanoid features, including most prominently the cephalization of sensory organs, but also including two arms and two legs and a large brain case, I know it’s almost certainly a fake. There’s no reason I can think of to believe that life—and I’m including intelligent life here—on other planets or worlds will be based on that principle.
Having said that, of course, I can’t rule it out either. Of all the trillions and even quadrillions of planets that must exist in all the galaxies in our universe, could there be a planet or two where evolution has taken the road to cephalization? To put it more simply, are there beings that actually look like us? Definitely possible. But considering the variations of conditions that exist on the planets we’ve detected so far in our galaxy, (and that’s an extremely tiny proportion of the total) it’s much more likely that life will be quite a bit different in appearance than anything on Earth. We may not even recognize it.