Spandrels

“Spandrel” is a term from architecture, meaning the triangular areas above and on either side of an arch.¹ ⊕ ¹ Inevitably, it seems as though strictly speaking, the spandrels of San Marco that Gould and Lewontin reference in their paper are not true spandrels. This happens more often than you might think. Stonehenge is, similarly, not a henge. As in the photo above, these have become a site of ornamentation. Evolutionary biology borrowed this concept, to name features that arise as byproducts of other decisions. Medieval architects didn’t start designing spandrels as a site for additional carvings of ladies. They designed stone arches, which produced extra triangles of space, which then became a new site for innovation. “Spandrel,” in the more general sense, then, has become a term for the inevitable byproducts of architecture, I would argue, whether performed in the physical world or digitally.

Who among us has not looked at a pre-existing structure and thought “huh, I bet I could stick something there. It would work”? It’s the main way of doing digital architecture (whether technical or information) when you’re not thinking about it hard or it’s nobody’s job. I would argue that the use (and over-use) of spandrels is the main way that Big Balls of Mud get created, because spandrels easily bring with them architectural debt. It’s not that they’re bad, but a feature arising from a spandrel easily becomes table-stakes, which means that the underlying structures can’t be removed without losing the essential feature.

This happens much more frequently than we like to think, because adaptationism is such an endemic bias in Western thought. Adaptationism tells us that features exist the way they do because they’re well-suited for the job they’re asked to do. Realistically, they’re often just load-bearing accidents.

References

Foote, B., & Yoder, J. (1999). Big Ball of Mud. Pattern Languages of Program Design 4. http://www.laputan.org/mud/?ref=coding-horror

Gould, S. J. (1997). The exaptive excellence of spandrels as a term and prototype. Proceedings of the National Academy of Sciences, 94(20), 10750–10755. https://doi.org/10.1073/pnas.94.20.10750

Gould, S. J., Lewontin, R. C., Maynard Smith, J., & Holliday, R. (1997). The spandrels of San Marco and the Panglossian paradigm: A critique of the adaptationist programme. Proceedings of the Royal Society of London. Series B. Biological Sciences, 205(1161), 581–598. https://doi.org/10.1098/rspb.1979.0086