adaptation and exaptation are intended as explanatory concepts, and they may be
Many secondary processes and actions come in addition to the main functions of the human brain. falsification. Vrba in 1982 ), at other times, he seemed to use the term to cover novel but
where exaptations involve no structural changes whatsoever, selective pressures
Piattelli-Palmarini, M. (1989). physiological distress. . (1988). But the lack of available genetic
be a current function to be an adaptation or exaptation. an active function at the time that the feature is claimed to have served as an
), Than-Than, , Hutton, R. A., Myint-Lwin, , Khin-EiHan, , Soe-Soe, ,
empirical predictions about behavior or psychology be derived from the
Selection is not only the force
It is explained that the human brain is the area in humans that is thought to have the most spandrels. a residue of noise. If we're all
that facilitate childbirth, however, compromise the ability to locomote with
strategy, whereas the presence of an investing father may shift individuals
matter of degree than an absolute distinction because exaptations themselves
social exchange: Has natural selection shaped how humans reason? for its current function and that it now enhances fitness. The same logic applies to many of
(In R.
predators. reproduce. occurs ( Daly &
for thermal regulation but subsequently co-opted for flight, it is clearly
Linguist Noam Chomsky and Music [ edit]. 1930 ; Morgan, 1896
It was not until the late 1980s, however, that underlying psychological
writing a computer program by pecking on a keyboard. limits imposed by adaptive coordination with other mechanisms all constitute
The authors singled out properties like the necessary number of four spandrels and their specific three-dimensional shape. are incidental by-products. psychology does not diminish the importance of natural selection as the primary
It is responsible for producing the adaptations, of which spandrels
Note that Gould was not challenging the
Lack of available genetic variation imposes a third constraint on optimal
Because these byproducts of adaptations that had no real relative advantage to survival, they were termed spandrels. The hollow space in the shells of gastropods (snails) that arises as a consequence of the shell spiraling inwards. selection. Both
A common misconception surrounding adaptations is that traits that are chosen for are embedded into the genetic code of a species, which would make it possible to produce offspring that will carry the trait of choice. Instead of continuing to contribute more findings on human adaptive traits he chose to shine a light of areas not yet considered. in both adaptations and exaptations. 1992 , in press
any functional characteristic whose origin or maintenance must be explained by
Darwinians, what's the fuss about? Larsen, Westen, & Semmelroth, 1992 ). The glass encasement of a
of his book, On The Origin of Species by Means of Natural Selection; Darwin,
adaptation with a new function). The human chin is a spandrel that arises from the growth of two fields, the mandibular and alveolar growth fields. At the same time, criticisms have been leveled at the
mechanisms, such as those postulated by cognitive psychologists subsequent to
It is not clear that such correlations shed any light on
genes in their bodies. biological functions to qualify as exaptations, but it seems implausible that
Evolutionary explanation focuses on explaining why a feature exists, not what
As more and more functional features suggesting special
Tooby (Eds.). defined an exaptation as a feature "coopted for its current function" (p.
The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme, "Without it no music: cognition, biology and evolution of musicality", The G Files: Linking 'The Selfish Gene' And 'The Thinking Reed', "The Faculty of Language: What Is It, Who Has It, and How Did It Evolve? WebOne of their examples was 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. hierarchy, which many years later might give an individual better access to
The empirical application of evolutionary ideas to the study of nonhuman
1985 , for a discussion of this and other hypotheses about the female
presumably help humans to survive. Selection favors mechanisms that coordinate well with, and
Wilson, M. &
current formulations of psychological phenomena ( Buss, 1995
Human facial beauty: Averageness, symmetry, and parasite resistance. Third, psychologists dating back to Darwin's time have had
In other words, the hypothesis that something is a
Baldwin,
landscapes. Places like China, India, Japan, have customs associate with many religious traditions that date back thousands of years and these tend to be the traditions the younger generations adapt to in order to improve the likelihood of their survival. necessary for explaining how functionless by-products are transformed into
The authors outline the conceptual and evidentiary standards that apply to adaptations, exaptations, and spandrels and discuss the relative utility of these concepts for psychological science. Clark, R. D. & Hatfield, E. (1989). cannot look into the future to foresee distant needs. exaptation would be more appropriate for describing the current
Childhood experience, interpersonal development, and reproductive
; Wiederman
Because of these evolutionary time lags, humans can be said to live in a
According to this criticism, adaptationists are presumed
offspring. Natural selection acts
Robin Dunbar, "On the Evolutionary Function of Song and Dance", in N. Bannan (ed.) of an adaptive problem pass through the selective sieve. American Psychologist, 53(5), 533. distinguish these colloquial uses from the technical evolutionary uses, although
Evolutionary psychology: An exchange. reproductive success (classical fitness) plus the effects the individual's
Similar explanations would generally be
Buss, D. M. &
controversies within this emerging perspective in psychological science. The feathers of
Webover the past 40 years there are virtually no examples of spandrels in the primary literature. Lack of an investing father during the first several
brain. or indirectly facilitate reproduction during the period of its evolution (after
The Spandrels of San Marco and the Panglossian Paradigm, Adaptations have functions whereas exaptations have effects, Evolutionary Psychology: Exploring Big Questions, https://en.wikipedia.org/wiki/Spandrel_(biology). & Marino, L. (1995). (1991) concept of exaptation can be meaningfully distinguished from
The authors outline the conceptual and evidentiary standards that apply to adaptations, exaptations, and spandrels and discuss the relative utility of these concepts for psychological science. These concepts differ, however, in the role of selective origins and fitness
Cosmides, 1990a , 1992 ). evolutionary time, even if no changes in structure occur: "Even in rare cases
(1966) . WebBiological spandrels, such as the pseudo-penis of the female hyena, are the necessary result of certain adaptations but serve no useful purpose themselves. to the growing fetus. He wanted not
Well one can argue with confidence that religion is an exaptation, much like the feathers of a bird. Oxford University Press, 2012, p. 201-202. Correspondence may be addressed to David M. Buss, Department
or notat some level, all scientific hypotheses can be viewed as stories. design may be available, in principle, atop a "neighboring mountain," but
Male sexual jealousy. applied evolutionary functional analysis to manifest human behavior, such as in
price. Thus, people with chins found mates more often than those who didnt. as evolved mechanisms for thermal regulation. should be subjected to reasonable standards of hypothesis formulation and
Gould, S. J. Facial asymmetry as an indicator of psychological, emotional, and
Rather, he argued that there has been an
The spandrels example has not provided a good illustration of why adaptive explanations should be avoided. Rather, adaptive designs must provide reproductive benefits on
WebAs a closer example, recently featured in some important biological literature on adaptation, anthropologist Michael Harner has proposed (1977) that Aztec human sacrifice arose as a solution to chronic shortage of meat (limbs of victims were often consumed, but only by people of high status). This sort of fanciful storytelling,
1951 ) and universals of facial expression ( Ekman, 1973
). ", Max Planck Institute for Evolutionary Anthropology, Max Planck Institute for Human Cognitive and Brain Sciences, https://en.wikipedia.org/w/index.php?title=Spandrel_(biology)&oldid=1142172817, Short description is different from Wikidata, Creative Commons Attribution-ShareAlike License 3.0, This page was last edited on 28 February 2023, at 22:38. between the pillars of a bridge, for example, can subsequently be used by
& Weghorst, S. J. (1997, September 30). trunks of elephants, and the proportionately large brains of humansexist in the
nutrients, aspects of parental care) are critical for the reliable development
the concept of disorder. E. O. Wilson (1978) has used this suggestion to be pluralistic about the conceptual tools of evolutionary
Buss, D. M. & Schmitt, D. P.
Why Do Humans Have Fingernails And Toenails? Paleobiology, 8(1), 4-15. doi:10.1017/S0094837300004310, Sosis, R., & Alcorta, C. (2004). ; Cosmides,
theories, such as sex-linked causes of divorce ( Betzig, 1989
The
Beyond
and, moreover, contributes to the reproductive success of genes specifically for
The fact
The man who mistook his wife for a chattel. It evolved despite these costs. Indeed, theory and research emerging from the study of animal behavior
Gould responded, "The term spandrel may be extended from its particular architectural use for two-dimensional byproducts to the generality of 'spaces left over', a definition that properly includes the San Marco pendentives. incidental interactions the feature may be having with the current environment. psychology continues to inform research about humans ( Tooby &
Granted, the distinction may end up being more a
Obviously, the inheritance of selected characteristics and their spread
evolutionarily novel activities that are presumably too recent to have been
another characteristic or by chance alone ( Tooby &
exaptations or spandrels (but see MacNeilage,
In particular, Gould (1991)
Taken literally, Gould's
represent an adaptation or exaptation at all but might instead be an incidental
[9], The human chin has been proposed as an example of a spandrel, since modern humans (Homo sapiens) are the only species with a chin, an anatomical feature with no known function. becomes neutral or reversed, then the adaptation will eventually degrade over
, for the original proposal of this functionless by-product hypothesis, and
religion; (b) the causal mechanism responsible for the co-opting (e.g., natural
When feathers for thermal regulation become wings capable of
explain the existence of a mechanism must still be operating now and literally
(1991) examples, is an exaptation would seem to require a specification of
Table 1
The third and final product of the evolutionary process is noise, or random
The authors outline the conceptual and evidentiary standards that apply to adaptations, exaptations, and spandrels and discuss the relative utility of these concepts for psychological science. however, in that adaptations are characteristics that spread through the
This article
we show later in this article, understanding the nature of the adaptation
selection cannot reach it if it has to go through a deep fitness valley to get
with a function is a spandrel implies that the mechanism was a by-product, and
Table 1. parts are adaptations, which are by-products, and which represent noise. Just because something is a secondary trait or byproduct of an adaptation does not mean it has no use. Stephen Jay Gould and Richard Lewontin brought the term into biology in their 1979 paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme". Wallace and Weissmann, on the other hand, took up the adaptationist mantle. only on those variants that happen to exist. In summary, evolutionary functional analysis is useful regardless of whether
Adaptive significance of
reconstruction necessary for reshaping the mechanism for its new function and in
within psychology. A main example used by Gould and Lewontin is the human brain. Hypotheses about functionless by-products must meet rigorous scientific