That's an interesting article. I've read about how regularities in biology (heart rate, breathing, anatomical symmetry) map onto an appreciation for aesthetic regularities. I don't think it's too surprising that the things that constitute bodily comfort also constitute some form of visual comfort. We tend to look for patterns, and it's reasonable to assume that our attraction to certain visuals is as biologically conditioned as it is socially.
The authors present an interesting account of our evolutionary relationship to visual aesthetics; but I have to say, they appear to have a very limited knowledge of scholarship on modern art, and to lump all modern art into the category of the "almost century-old theory of visual modernity"--a term that homogenizes art that falls under the banner of "the modern," and reduces differences within the field to insubstantial accidents. For starters, the avant-garde was only one small portion of visual modernity. One of the most famous figures in modern architecture was Le Corbusier, whose buildings exhibited a variety of visual features--some of which feature strong centers and stable boundaries, some of which don't.
The authors don't mention brutalism--a prominent descendent of modernism in architecture--despite the fact that brutalism is all about strong centers (one could argue that brutalism itself constitutes a "strong center") and borders. They also don't mention recent research on the presence of fractal patterns in modern art, from the controversial examination of
Jackson Pollock's paintings to the recent book
The Fractal Dimension in Architecture. The authors of the latter text argue that fractal complexity in architectural structures reflects the demands of the structure; in other words, if the building needs to accommodate more people, it tends to exhibit more complex architectural patterns. This argument shines light on one factor that the authors of the Preservation Leadership Forum essay don't even consider: functionality.
I find that their argument gets a little murky at this point. For example, look at the photos they use contrasting a purportedly "modern" building with the Piazza di Spagna in Rome. They claim that the modern building betrays its wear and tear more than the older building does--a claim that I think is very true. The problem here is that the modern structure they've chosen is a purely functional structure and exhibits none of the qualities they attribute to visual modernity: namely, attention-grabbing, artistic packaging, and lack of correspondence to larger wholes. I also thought that phrase "Look at me, I'm a modern art object!" was adorably laughable; I know they're trying to be serious, but I don't think they've done all their research when it comes to visual modernity. Or perhaps more accurately, I think they've imposed certain specific qualities from avant-garde visual modernism onto an entire century's worth of architecture, but then haven't bothered to note disparities within architectural history or, for that matter, to be consistent in the kinds of buildings they focus on. In fact, I would argue against these authors that the majority of modern buildings (such as the one they included in a photograph) aren't constructed according to the modern traits they've specified, but according to the demands of functionality and affordability. If modern buildings don't correspond to their surroundings, it's not because of artistic credo but because of structural and environmental demands; but these don't always translate into visual pleasure.
Lastly (for now), I'd ask them why they're so insistent upon homogeneity in an architectural ecosystem. Or, if homogeneity is too harsh, at least complementarity. Urban architecture reflects history as much as it does an artist's ideals or the structural demands of city space. If you visit Copley Square in Boston, and stand in front of the public library, you'll probably be able to see no fewer than seven different styles of architecture, all reflecting different histories. Now, no one really lives in Copley Square, so this probably makes some difference; but it's quite magnificent to stroll through such a small space (relatively speaking) and see so many different architectural styles. If you go one block over to Newbury Street, you'll see far more architectural regularity. To me, this seems like a more democratic differentiation of architectural appearances--not the (as I see it) homogenization of architecture that these authors seem to be championing.