Spandrels, Exaptations, and Raw Material

Abstract

STEPHEN JAY Gould and Richard Lewontin introduced the spandrel as a biological metaphor in a 1979 paper entitled “The spandrels of San Marco and the Panglossian Paradigm: a Critique of the Adaptationist Programme”. Architecturally, the curved triangular spaces, called pendentives, formed above and between two neighboring arches in a vaulted roof supported by four arches, are a type of spandrel (Fig. 15.1). Technically, a spandrel is a “space left over” between portions of an architectural structure, such as the vertical spaces between steps on a staircase or the “spandrel courses” on the sides of high-rise buildings, between the windows of one floor and the windows of the next (Fig. 15.2). As Gould explained after he had delved further into the architectural details, many architects use the term only to refer to two-dimensional spaces, while a continental European school does consider three-dimensional forms, like the San Marco pendentives to be spandrels (Gould 1997, 2002, p. 1250).