Forums: Index > Evolutionary psychology forum > Spandrels

A spandrel is a term coined by S.J.Gould and R.Lewontin (1979a) for traits which confer no adaptive advantage to an organism, but are 'carried along' by an adaptive trait. Their example being the lengthening of a bone in the hind limb of the Giant Panda, as a result of the lengthening of the corresponding bone in the forelimb. The bone in the forelimb has adapted to perform a function similar to that of an opposable thumb. The change in the hind limb, arguably, confers no adaptive advantage, whereas the change in the forelimb certainly does. The important implication of this idea for Evolutionary Psychology being, that therefore not every trait can be accounted for in terms of adaptive advantage. For instance, Gould puts forward the hypothesis that language itself in humans came about as a spandrel: "Natural selection made the human brain big, but most of our mental properties and potentials may be spandrels - that is, nonadaptive side consequences of building a device with such structural complexity" (S.J.Gould. The Pleasures of Pluralism , p.11) But of course, once a trait confers an adaptive advantage, as arguably most of our "mental properties and potentials" do, it is no longer a spandrel, and thus opens the debate concerning the importance of the concept of spandrels.

David Buss used the term "by-product" to refer to "spandrel." An example he uses to contrast an adaptation and a byproduct, (i.e., spandrel), is an umbilical cord and a belly button, respectively. I agree with the idea that many aspects of the human mind could be spandrels. However, I find it difficult to believe that most aspects of the human brain are spandrels. The human brain is extremely costly, and it doesn't seem likely to me that the human brain would have evolved the way it did unless its structure and function gave humans a significant adaptive advantage. (Not to mention the fact that humans are an extraordinarly successful species, occupying virtually every type of niche on the planet!) You may also like to check out the article, psychological adaptation, and check out some of the papers listed at the bottom. Comments? Jason Bessey - Jaywin (talk) 17:13, 9 January 2007 (UTC)
Well i completely agree. When you think about it, this suggestion of Gould in PofP is completely implausible. So most of the brain has no function at all? Even the term potential invites the question: "potential for what?" Either he means that most of the brain really confers no advantage to us, an absurd claim, or (what i think he really means) that many properties started off as spandrels, but thats no real challenge to EP, except to the extent that you must acknowledge the complexities of evolution (But then another common criticism of EP is that it fails to do just that). So much of ev-psych comes down to debates about origins and function i think, its really fascinating. Orgone 04:22, 29 April 2007 (UTC)
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