But what does it do?

Last night we were watching Animal Homes; a woodrat (“pack rat”) was adding found objects to its impressively-large nest in the forest. The voiceover explained that these rats love anything metal and shiny. They don’t seem to make any “use” of them; they just add them into the structure of twigs and branches, seemingly at random. There was no mention of using them to attract a mate, as birds of paradise do, for example. As is common in these documentaries, the narrator ended with something to the effect of, “scientists aren’t sure what purpose this serves.”

I’m not an evolutionary biologist, obviously; if anyone figures out a “purpose” for the woodrat’s collecting of bottle caps and lost costume jewelry, it won’t be me. I do know just enough about evolutionary biology, though (thanks to good teachers) to know that evolution does not require a “purpose,” as we think of it, for everything. Just because a behavior doesn’t serve a “purpose” doesn’t mean evolution will select against it—because such behavior doesn’t necessarily have a negative effect on the organism’s ability to survive long enough to reproduce and rear young.

I’m using the word “purpose” here in a fairly narrow sense; to convey what in the history of technology we call functionalism—the assumption, perhaps unconscious, that everything must have an explanation centered on function—everything has to do something to make any sense. This is a fallacy; it isn’t true.

It may be that woodrats collect shiny objects just because they like them; if so, our language serves perfectly well in expressing the reality of what’s going on there. Maybe that’s not enough, though, for that trait to reproduce itself so universally in the species. Maybe if this behavior weren’t part of a wider behavior that had a real benefit to the woodrat, it would just pop up randomly, go away, pop up again, but never “take over.” So, perhaps it’s just part of the behavior of collecting objects to construct a large nest that does serve the animal—serves all of them. This is all deliberately tentative because, again, I’m not an evolutionary biologist.

What I can be more confident about is human technology. The use of evolutionary language in the history of technology (and archaeology) is controversial, and it has been misused in the past as a form of teleology—determinism. Used as a model, it takes away human agency—decision-making—and thus distorts the reality of how technology works.

As a metaphor, though, I find it quite useful. This is a good case of why. Good historians of technology reject functionalism; we know that the way humans manipulate the material world goes far beyond utility. Aesthetics is the most obvious example. The intersection of aesthetics and utility (form and function) is an endlessly-interesting place to explore, but we accept that people make technological choices that maximize the sensory pleasure we derive from the result—even when designing, say, a toaster.

Among the possible counterarguments to functionalism is the vestigial trait, in evolutionary terms: something that used to have some identifiable purpose, that no longer does, but it’s not hurting anything so there is no selective pressure to eliminate it. But we have to be careful when we label something “vestigial;” when I was growing up, we were taught that both the human appendix and the hip bones of whales were vestigial. Now, according to a quick and dirty online search, neither is considered vestigial, because researchers have found evidence to support functions for each in the modern animal.

It’s hard to separate a vestigial trait from aesthetics in technology. I did a piece called “Retro” earlier in this series; I’m pretty comfortable saying that most “retro” technology, since it’s consciously intended to be “retro,” comes from aesthetic sensibilities. I think vestigial traits are more subconscious; more about the way we’ve always done something, and we still do this bit this way just because we always have and we’re not aware of any need to change it so it doesn’t occur to us to do it. Change carries costs—or potential costs, at least. On the other hand, if conditions change, then not changing might carry a higher cost. If the retention of a feature in an early-modern ship, for example, has material and/or labor costs higher than an available alternative, how do we explain that retention? Can we go beyond aesthetics?

On 17^th- and 18^th-century merchant ships, we believe that some features that are otherwise difficult to explain were adopted from naval vessels for both security and prestige. (“Prestige” can’t be fully-separated from aesthetics, but it serves a social function, so it’s somewhat distinct.) We suspect, for example, that the sprit-topsail on square-riggers (don’t worry about what that is if you don’t know) was retained, even after a viable and less-costly alternative was becoming more common, because it was a long-established feature of warships—royal ships, intimidating ships. Navies don’t have to care about labor costs the same way merchant owners do. There would have been pressure on merchant owners to swap out the more complex, labor-intensive sprit-topsail for the triangular headsail all modern sailors are familiar with—but there may have been just enough counter-pressure from the cultural sphere to delay it. So, one way to think of this would be that we have to consider other sorts of costs and benefits to explain a continuity or change.

One way to start trying to understand a technology is: Is there a different way of doing this that would not affect how it works? In asking that question, though, we’d also have to ask: Is there a different way of doing this that would not detract from the aesthetics of it, given the sensibilities of the makers/users? If we left that question out, we’d be falling into functionalism. So, to really know would require some understanding of the aesthetic sensibilities of the makers/users.

It’s actually easier to cite examples of vestigial vocabulary in the history of technology than an actual clearly-vestigial feature, at least for me. The vocabulary of watercraft technology is full of vestigial terms; the gunwale (gunnel) of your canoe, the top edges of the sides, is, first, no longer a wale, unless your canoe is plank-on-frame wood construction; and second, I seriously doubt your canoe has cannon poking over the top edges of its sides.

Maybe the woodrat’s compulsion to collect objects that seem to serve no purpose for it is a vestigial trait—and/or, it’s aesthetic. Modern biologists seem to have freed themselves from their analogue to functionalism, relative to their late-Victorian antecedents. They seem to be willing to acknowledge the possibility that animals do things because they like to, and that doesn’t seem to contradict the basic principles of evolution by natural selection.

On the other hand, maybe the behavior has an identifiable purpose; we just haven’t identified it yet. We know that a lot of previously-mysterious animal behavior can be understood once we understand specific ways that animals’ senses and sensory-processing differ from ours. Butterflies see ultraviolet light. Dogs and bears have an olfactory world off-limits to us.

Historians of technology have realized that people sometimes make and use things the way they do because they know how, and because no obviously-preferable alternative way of making and doing them presents itself. When conditions change, perhaps then there will be pressure for a change-adaptation. Until they do, it’s fine to just keep making and doing what works. Or what feels good. And even if changing conditions introduce pressure for change, other pressures may push back. If we want to understand a past people’s technology, we have to look into all of this; and we have to accept that some key piece of understanding may be lost to us, leaving us guessing.

If Steve Kinsey’s reading this, and I’ve made a misstep, he can take me to school.