duck sex, beauty, and architectural evolution

9780385537216The reading list on this trip has been Richard O. Prum’s The Evolution of Beauty: How Darwin’s forgotten Theory of Mate Choice Shapes the Animal World—and Us.  It’s made a host of year-end top ten lists, and I’ll chime in by saying it’s engaging and convincing—if you can stand a few raunchy bits and a truly terrifying account or two of sexual behavior in wildfowl.


As someone who uses Origin of Species and (more to the point) D’Arcy Thompson’s On Growth and Form to model how innovation occurs in construction and design, I also think that Prum’s argument has some consequences for how we think about architecture, and in particular the way we talk about structural or functional ‘honesty.’  Darwin is often interpreted, Prum explains, in strictly adaptationist terms.  In other words, for any physiological or behavioral feature, we should be able to find a demonstrable benefit that enables an organism to better fit its environment than it would if that feature were lacking.  This works fine for finches’ beaks, opposable thumbs, and bird songs, but it always runs up against, say, the peacock’s tail—which Darwin himself admitted gave him fits.

peacockPrum notes that there are several adaptationist theories that go some way toward explaining that tail.  It’s often been explained as a signal that the male in question is so fit for his environment that he can afford the material expense, and the implications for running speed and (lack of) flight that comes with it.  Alfred Wallace, Darwin’s contemporary and interpreter, picked up this theory and, according to Prum, it’s been evolutionary biology dogma ever since.  But Darwin himself suggested that, in fact, there may be no good adaptationist explanation for that tail, or for the elaborate mating rituals of bowerbirds, for instance, which spend enormous amounts of time and energy building structures that are used only for courting females.  It may be, instead, that female choice and male physiology are both involved in a self-reinforcing spiral.  Females that, for whatever reason, happen to prefer big tails will select males with bigger tales, thus passing on those genes to their offspring, who will, in turn, attract more females who prefer bigger tales.  There’s no tangible benefit, necessarily, to a big tail—it just happens because there’s—wait for it—an aesthetic preference that ends up being instantiated in actual physiology.

nautilus-e1332253871149There are interesting consequences here for a model of technical and stylistic development in architecture.  “Strict adaptationist” theories of architectural expression—especially structural expression— are best illustrated by Louis Sullivan, whose “form follows function” is the adaptationist gospel distilled into a pithy aphorism.  D’Arcy Thompson’s On Growth and Form blows this up slightly, pointing out that the functional benefits of a physiological feature (or, let’s assume, a behavioral one) have to be balanced with the investment of material and energy it takes to grow that feature—thus his emphasis on efficient forms like the radiolarian’s microscopic geodesic skeletons, or the statically-tuned arm bones of vertebrates everywhere.  Thompson also emphasized that the amount of information it took for an organism to create such a structure had to be efficiently stored and recalled as well, meaning that algorithms and patterns are critical in physiology.  The Nautilus shell is his most jaw-dropping example, but he also explains the spiral patterns of sunflowers and pine cones by showing how individual seeds emerge and compete for space according to mathematical rhythms.  It’s not miraculous that such patterns emerge—it’s inevitable.

All of that makes for a pretty compelling argument that engineers and architects follow, more or less.  We favor similar processes of functional, fabricational, and algorithmic efficiency when we can.  And in addition to being sufficient to the task desired (structural or otherwise), and efficient in getting that task accomplished, we know that there’s a process of signaling that fitness to purpose and to means that is often a key element in mate selection in the natural world, and in architectural expression in the human world.  In nature, this might be a physiological sign of strength, or fecundity.  In design, it’s more a promise of functionality or durability, what Donald Norman calls “affordances.”  We select, for instance, one branch or another when climbing a tree based on how robust it appears as a structure, or we select a shelter based on whether it looks like it will resist an oncoming storm.  This translates even to less survivalist instincts—we’ll more quickly choose an implement that more apparently fits the hand, or that looks less likely to break under use.

Prum’s argument, though, offers a powerful parallel process of selection that rings true in the design world, as well.  Aesthetic selection means that some instincts end up becoming engrained even though they offer no additional benefit or purchase on the world out there.  “Beauty happens,” is his distillation of this effect into a Sullivanesque aphorism.  And, sometimes, this comes at the expense of actual function or efficiency in the natural world, though more often it’s something of an adjunct.  It’s difficult to imagine this beauty instinct overwhelming common sense mate selection—the peacock’s tail is about as far as the natural world goes in producing beautiful though maladaptive physiology.  But it certainly explains any number of adaptations that don’t have an immediately apparent functional or efficient cause.

For a while now, I’ve taught basically a strict adaptationist version of construction history.  We look at ‘adaptations’ such as groin vaults, or curtain walls, or iron framing, as developments that have some basis in experimental iteration, that get deployed in a competitive (usually economic) milieu, and that prove themselves against a range of existing, proven techniques—at least until a development comes along that better fits the same environment, or until that environment (financial, social, political, sometimes) itself changes.  The “beauty happens” argument rings true, though, in that this story only covers so much—it can only suggest some origins, for instance, of the classical language, and even then what it comes up with is pretty speculative (see, e.g., Viollet-le-Duc’s skewering of the supposed “origin” of the Doric column).  A Prum-ian theory of architectural development would suggest, instead, that a lot of what we see through construction history—groin vaults and their ilk—do follow a strictly adaptationist model.  But there’s also plenty that simply occurs because of initial tastes or preferences or even modest successes that, because of their popularity, evolve on a more or less separate, purely aesthetic path.

So, we have three models now:  the Alfred Wallace argument, which states that every form has and is adapted to a purpose; the D’Arcy Thompson argument, which states that every form has and is adapted to an efficient method of growth or assembly; and what Prum argues was Darwin’s original argument, which states that sometimes forms are the result of purely aesthetic preferences, and that these evolve according to their own logic.  To which the obvious response is “no kidding,” but this adds some evolutionary weight to the influence of style—fashion, even—in design.

Sobering for an architectural ‘pure adaptationist?’  A bit.  But I think there are good reasons to stick to one’s guns.

First, there’s an interesting parallel here with a problem that any good A.I. fanatic in the field will cop to.  When using a genetic algorithm program like Galapagos, which develops solutions to parametric problems and then interbreeds these to develop new and, one assumes, more efficient solutions, the software will often fool itself into thinking that it’s found the best possible solution, when in fact it’s been sidetracked into a solution that is locally best, but that might not be as good as other, untried solutions elsewhere in the design space.  (Think of this as a table surface with several funnel-shaped depressions of different depths.  That’s the design space.  Throw a bunch of marbles onto the table, which represent attempts at solving the problem. Some of them will find the deepest funnel, but some will also settle into shallower funnels and, from their perspective, their job will seem like it’s done).  In other words, the distinction that Prum makes between adaptive solutions and aesthetic solutions may be a very blurry one, and the presence of localized, aesthetic solutions doesn’t preclude either the logic or attractiveness of much more convincing or attractive solutions elsewhere in the design space, whether that space involves organisms, bridges, can openers, or buildings.

marcellus 1Second, if we re-read a bit of architectural theory, we already know that this is the case.  We call some things beautiful that are, as Alberti suggests, “proper and innate and diffused throughout the whole,” as opposed to “something added and fastened on.”  [De re Aedeficatoria, Book VI].  This is echoed by Viollet-le-Duc, who saw this as the explicit difference between Greek and Roman architecture (“Greek architecture may be best compared to a man stripped of his clothes, the external parts of whose body are but the consequence of his organic structure…. Roman Architecture may be compared to a man clothed…. the dress may be good or bad…but it forms no part  of the body.” [Discourses, III].  And, of course, it recalls Sullivan’s organic philosophy.

30c525bc1836b1f4bf36ef69ae3d4626--this-little-piggy-barnyard-animalsBut there have been plenty of theorists who’ve argued precisely for Prum’s aesthetic selection—that is, for beauty in architecture that has nothing to do with fitness or even signaling of fitness.  Both Edmund Burke and John Ruskin refuted the notion that fitness to purpose and beauty were necessarily linked.  Burke, famously, pointed out that the snout of a pig is perfectly suited for “digging and rooting,” yet hardly (by the day’s standards, anyway) ‘beautiful.’  “’High art,” thought Ruskin, “differs from low art in possessing an excess of beauty in addition to its truth,” suggesting that Ruskin, too, thought beauty was something added to the fitness of a painting to its model, or (extrapolating here) a building to its function or materials.  Neither writer was able to come up with what, exactly, this was, but that’s sort of Prum’s point—there’s no accounting for taste, we either feel something is beautiful or not, independent of any objective standards, and the feeling, the pleasurable and pretty well inexplicable firing off of satisfied neurons, is closely linked to how we and many other species end up selecting our mates.

Prum speculates on evolution in art (if not architecture, per se) in his final chapter.  Spoiler alert: there are intriguing parallels between what he identifies as the “desire/display” feedback loop in sexual selection, especially in birds, and the dialogue of artistic production and criticism that forms what philosopher Arthur Danto called the “artworld.”  Prum uses Mozart as an example, noting that he “transformed his audiences’ capacity to imagine what music could be and do.”  These transformative experiences among those who experienced such innovation “then fed back upon future composers and performers to advance the classical style.”  Expectations are changed or raised by one innovative artwork, and then future artists not only have slightly larger creative reservoirs from which to draw, they also have those raised expectations to meet, or further challenge.  I think this applies to technology, too, though the ‘audience’ for innovations like metal framing or plate glass windows has been composed not just of culturally interested specimens, but of financially interested ones, which can only make the process more intense and more critical.

calatravaNot sure where this is all heading, but it’s a nice kick in the head and a great read.  I think it still leaves open the ethical critique of projects that stray far from adaptationism—we may regard Calatrava’s PATH station as a remarkable, sensational, and even beautiful space, but the resources that went into it could have been spent toward more purposeful ends, e.g.   Prum nicely encompasses all kinds of discussion about beauty in the human world—whether it is an inherent quality that ornament draws out (Alberti), or whether ornament alone can achieve it, an idea that starts rumbling in the Baroque and emerges full-blown in Rococo architecture.  Worth adding to the holiday reading list…

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