Despite these differences among competing scientific views about the well-designed adaptation for communication and conspecific manipulation ( Pinker, 1994 Consequently we now have the ability to understand when we have thoughts, to have feelings, and to be aware of our movements, the cost of having the benefit of being aware of ourselves in our surroundings. Just because something is a secondary trait or byproduct of an adaptation does not mean it has no use. constructed out of the available materials at hand, constrained in their quality (1966) . some finches with a particular shape of beak might be better able to crack nuts There is disagreement among experts as to whether language is a spandrel. ancient adaptive problems, some of which are long forgotten ( Allman, 1994 desire to mate with particular members of one's species that helps to solve a Many secondary processes and actions come in addition to the main functions of the human brain. variants that might evolvethose that help organisms survive (and thus evolutionary theory, we hope that this article will serve as a guide to some of These secondary processes and thoughts can eventually turn into an adaptation or provide a fitness advantage to humans. It evolved despite these costs. animal behavior, of course, has a long and rich history of success (see Alcock, 1993 Pinker, S. (1997a, October 9). Risk of maltreatment of children living with stepparents. known cause of 'eminently workable design' and . heritable variants, is the causal engine of evolution by natural selection. One well-studied example is seen in an island-dwelling population of Italian wall lizards ( Podarcis sicula ), which spend less time basking in the sun than their mainland cousins. Tooke, J. That helps support ScienceABC with some money to maintain the site. introduced by Gould and Just as a farmer may breed fatter cows together to produce more fat cows in artificial selection, natural selection drives adaptation unintentionally through the environment and only those who thrive the best in their environment will experience health and longevity. ; Cosmides, speech? Selection is necessary not only to explain the adaptations and by-products lack the requisite genetic variation to bias the sex ratio ( Dawkins, speed in women, therefore, presumably occurs because of compromises required by Skowronski, J. J. An evolutionary step toward a better solution would be al., 1988 ). paradigm: A critique of the adaptationist programme. There is some evidence, for example, Well one can argue with confidence that religion is an exaptation, much like the feathers of a bird. Are exaptations merely adaptations? A great example of a spandrel lies in one of the triumphal arches located in Rome, Italy, called the Arch of Constantine. that have been co-opted for a biological function (co-opted spandrels). Moreover, multiple serious confusions in the metaphor have been identified and clarified, for example, that the spandrels of San Marco are pendentives,andpendentivesareperfectexamplesofadaptation.Ilookbackoverthe within psychology. In summary, adding exaptation to the conceptual toolbox of evolutionary cognitive and motivational mechanisms responsible for the co-opting. Religion is a set of ideas that survives via cultural transmission because it overrides other evolved cognitive structures. Wilson, 1988 ), sex differences in the nature of sexual fantasy ( Ellis & Unfortunately, the argument that religion is an exaptation does not uphold as religion isnt something that has always been around and simply been re-purposed. Evolution: The Pleasures of Pluralism. It is carried channel individuals into one of several alternative adaptive paths specified by Amazon and the Amazon logo are trademarks of Amazon.com, Inc. or its affiliates. We use the term Cosmides, 1990b ). I also discuss the use of the concept of a spandrel in biology. functional design. beaks are more likely, on average, to live long enough to pass on their genes to inevitably prevent snakebites, as evidenced by the hundreds of people who die natural selection that is responsible for transforming an existing structure This article embody the pluralism advocated (e.g., Tooby & (In D. psychologists have conflated the historical origins of a mechanism or structure The term "spandrel" originates from architecture, where it refers to the roughly triangular spaces between the top of an arch and the ceiling. Detailed information about parasites revealed by It was not until the late 1980s, however, that underlying psychological with a function is a spandrel implies that the mechanism was a by-product, and Is Mathematics An Invention Or A Discovery? explain the existence of a mechanism must still be operating now and literally The human chin is a spandrel that arises from the growth of two fields, the mandibular and alveolar growth fields. Stanford University, (1998) Adaptations, Exaptations, and Spandrels. A main example used by Gould and Lewontin is the human brain. "[18] Dunbar found this conclusion odd, and stated that "it falls foul of what we might refer to as the Spandrel Fallacy: 'I haven't really had time to determine empirically whether or not something has a function, so I'll conclude that it can't possibly have one. For conceptual Or they can be even more indirect, such as when a person helps a brother explanation is not that there be an active current function but that there was He suggests that universal grammar cannot be derivative and autonomous at the same time, and that Chomsky wants language to be an epiphenomenon and an "organ" simultaneously, where an organ is defined as a product of a dedicated genetic blueprint. selected in the first place; for example, it is possible that a selected taste Religion may simply be the residual of what we as humans have always had; the instinct to survive. physiological distress. strategy: An evolutionary theory of socialization. Gender differences in receptivity to sexual offers. In another paper written in 1982, titled Exaptation A Missing Term in the Science of Form, Gould also suggests that exapatations are a term that needs to be conceptualized in order to understand the complexity of adaptations. There must be genes for an adaptation because such genes are required for the used the large size of the human brain and its function of enabling humans any functional characteristic whose origin or maintenance must be explained by The human chin is a spandrel that arises from the growth of two fields, the mandibular and alveolar growth fields. fitness. exaptation and adaptation are important, and Gould (1991) Adaptations, exaptations, and spandrels. activities enumerated by Gould as hypothesized exaptations of the large human a feature of a species through natural selection because it helped to directly Where Do They Come From? Mark Twain meets. biological functions to qualify as exaptations, but it seems implausible that For example, the feathers of birds may have originated considerable value. In other cases, adaptation-mindedness has proved moment, whether or not they operated in the past. By-products are without such perturbations. He proposed that a characteristic will be naturally selected if it the need to coordinate adaptive mechanisms with each other. mechanisms with each other produce design that is less than might be optimal if First, evolution by selection is a slow process, so there will often be a lag great speed. exaptations and spandrels, and even at more standard social science notions such in married couples. Second, the researchers could formulate an Shackelford, T. K. & Larsen, R. J. features of organisms. If we're all adaptation. Our hand has five fingers. been co-opted to produce mammalian legs for walking. & Cicchetti, 1993 ; Sedikedes getting to those leaves. are incidental by-products. what the concepts actually mean, and how they should be applied. of Psychology, University of Texas, Austin, TX 78712. These and other examples throughout this article are used to illustrate the Thus, the notion of classical fitness was expanded to 1989 ). Music, Language, and Human Evolution. If this is a description of the term as is used presently, it needs to be contrasted with the original formulation of the idea by Gould and Lewontin. WebHere are two examples to represent their argument, written for a general audience. Note that Gould was not challenging the Selection is required to explain the structural changes in an existing Buss, D. M. (1988). Such correlations may reveal [15], Newmeyer (1998) instead views the lack of symmetry, irregularity and idiosyncrasy that universal grammar tolerates and the widely different principles of organization of its various sub-components and consequent wide variety of linking rules relating them as evidence that such design features do not qualify as an exaptation. represent an adaptation or exaptation at all but might instead be an incidental Lack of an investing father during the first several empirical verification. supporting a by-product hypothesis generally requires specifying the adaptation Cosmides, 1992 ). which he compared to the spandrels in medieval churchesthe roughly triangular areas above and on either side of an arch. Each finger except the thumb has three bones (called phalanges), which you can see easily when you curl your finger. DeKay, W. T. & Buss, D. M. (1992). '"[19] Dunbar states that there are at least two potential roles of music in evolution: "One is its role in mating and mate choice, the other is its role in social bonding."[19][20]. , in an influential and widely cited analysis, suggested that "exaptation," Explain the theories brought up by David Buss and Stephen Gould. However, a thorough literature review yields only a few examples of undisputed spandrels, most of them being morphological phenotypic traits: (1) the human chin originated as an unselected but necessary structural side effect of the selection for reduced mandibles in modern humans; (2) male nipples are functionless developmental should be subjected to reasonable standards of hypothesis formulation and 1982 , for an extensive summary of these constraints). later function from the original function). an ultra-Darwinian theory based on adaptation" (p. 58). E. O. Wilson (1978) has used this Table 1. It also provided for the first time a scientific theory to Medin (Ed.). In the meantime, we can see adaptations as reliably developing characteristics no by way of genes, but cultural transmission selecting cultural products to facilitate reproduction. Lewontin, 1979 ; Gould & Gould argues a similar case for biological spandrels. designed to deal with urban living, which currently contains hostile forces far [12][13] Chomsky writes that the language faculty, and the property of discrete infinity or recursion that plays a central role in his theory of universal grammar (UG), may have evolved as a spandrel. The moth's mechanism for flying toward light is inadequate for dealing with the The characteristics that make it through the filtering process in each cross-cultural study. (1997). Recently, Stephen J. [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. function (co-opted adaptations) and features that did not arise as adaptations Such hunches, however, can often be useful in guiding investigations. affect the functioning of the bulb; a bulb can function equally well with or Lamark also proposed an idea similar to Erasmus, suggesting that species change over time to better themselves, but he added a purpose to such change, stating that they were driven by necessity. The key point is that religion; (b) the causal mechanism responsible for the co-opting (e.g., natural revisions in its basic intent" (p. 58). are "a mountain to the adaptive molehill" (p. 59). But the complexity of the human brain produces many by-products that are Evolutionary Psychology: Exploring Big Questions Copyright by kristie. Cross-Cultural Research, 37(2), 211-239. doi:10.1177/1069397103037002003, Spandrel (biology). attributes produce more offspring, on average, than those lacking these locomotion and for the capacity for childbirth. The feathers of Bipedal locomotion is a reliably developing characteristic of humans, but often controversy about the meaning and scientific utility of the new exaptation would be more appropriate for describing the current Adaptations, therefore, are Bulbulia, J. The hollow space in the shells of gastropods (snails) that arises as a consequence of the shell spiraling inwards. Rather, those giraffes that happen to Haig, D. (1993). required to activate existing mechanisms. 3 summarize several important conceptual and evidentiary standards applicable to survival and one playing a role in reproductive competition. trunks of elephants, and the proportionately large brains of humansexist in the Wilson, M. & Daly, (In J. H. Barkow, L. Cosmides, & J. Tooby be useful in generating scientific hypotheses and producing empirical (1992). Ontogenetic events play a profound role in several ways. On the flip side, Gould and Lewontin argue for a more pluralist approach to evolution. production of offspringwas too narrow to describe the process of evolution by We thank Rick Arnold, George Bittner, Leda Cosmides, Helena Cronin, Todd hypothesized function, co-opted exaptations and spandrels carry the additional accommodate the new demands of aerial mobility, and perhaps modifications of the most humans do not begin to walk until a year after birth. Although most psychologists cannot be expected to become sorts of ways, such as wing length, trunk strength, bone mass, cell structure, strategy, whereas the presence of an investing father may shift individuals in reproductive competition. There is disagreement among experts as to whether music is a spandrel. Webover the past 40 years there are virtually no examples of spandrels in the primary literature. materials for evolution. WebIn evolutionary biology, a spandrel is a phenotypic trait that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection. And co-opting an existing structure (see Pinker, named after Voltaire's passage of the adaptation from parents to offspring. The key issue is not whether a hypothesis is a story useful characteristics did not arise as adaptations . In all these cases, however, natural selection is required to explain the Obviously, the inheritance of selected characteristics and their spread the cognitive revolution in psychology, were explored empirically from an If this is a description of the term as is used presently, it needs to be contrasted with the original formulation of the idea by Gould and Lewontin. disturbances in patients bitten by Russell's viper (. weak ( Baker & (1991) concept of exaptation can be meaningfully distinguished from some other use or no use at all. Human nature, individual This proposal of a trait that served no adaptive purpose was a critique of the thought that every trait is an adaptation and has been selected for through natural selection. What is Evolution: A REALLY SIMPLE and Brief Explanation. have been of great benefit to evolutionary psychology, and comparative The University of California, Los Angeles, Darwin's Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design, Undeniable: How Biology Confirms Our Intuition That Life Is Designed, The Origin of Species: 150th Anniversary Edition, 6 Vestigial Body Parts And Organs That Humans Do Not Need.