Steven C. Hertler - Life history evolution: a biological meta-theory for the social sciences

The Author(s) 2018

Steven C. Hertler 1

As defined by the Cambridge Dictionary, the social sciences are a federation of disciplines dedicated to the study of the customs and culture of a society, or a particular part of this subject, such as history, politics, or economics. expands on this definition without changing its substance: A branch of science that deals with the institutions and functioning of human society and with the interpersonal relationships of individuals as members of society. As can be seen in these and other definitions, the social sciences are bound together under one banner by virtue of their shared mission to explain human nature and society. Equally important to note, the social sciences have unity of purpose even as they have no meta-theory; no foundation from which variables can be connected, causally sequenced, or ultimately explained.

Many social scientists feel the absence of such a meta-theory. Take the celebrated sociologist Charles Murray , who, as previously described (Hertler In both works, Murray continues describing his intuition thus:

Charles Murray is not alone. Social scientists of every variety routinely struggle to glean patterns, relate individual traits to group norms, and infer causal relationships among correlated variables.

Evolution has been advanced as this missing meta-theory. And of course, it is only through evolution that humans have been embedded within the natural world. Prior to evolutionary theory, most understood animals to be of a different order; subservient beasts to be exploited for the good of mankind. An evolutionary perspective, properly absorbed, contextualizes humans as Eukarya, Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, Sapiens . Evolutionary branching inferred through geologic time tells us so much about our function, origins, and history. Evolutions unifying utility has long been recognized within the biological sciences, as demonstrated by the following excerpt from Henry Ward Beechers Evolution and Religion written in 1885 (Beecher ; pp. 5051):

Faith in evolutions synthesizing ability was likewise precociously expressed in the writings of Robert G. Ingersoll () and is similarly found amidst the inadmissible evidence of expert scientists testifying in the 1925 State of Tennessee v. John Thomas Scopes . Evolutions sway extended steadily over the life sciences following the modern synthesis , wherein the likes of J. B. S. Haldane and Ronald Fisher reconciled the work of Darwin with that of proto-geneticist, Gregor Mendel .

For many social scientists, however, evolution was established as something to respect, but was also subject to neglect. Evolution remained a rarified background theory that seemed of little import to the questions that most social scientists were absorbed in asking and answering. A general reading of evolutionary theory provided the social scientist with some direction concerning human universals, but less so of particulars. Evolution may for instance explain what is common to all cultures, while not sufficiently explaining differences between cultures; just as evolution seemed to specify species-specific norms without thoroughly explaining differences within and between populations. As can be seen in the following quote, this is precisely the point that Marvin Harris , the anthropologist featured in Chapter , makes in his magnum opus, Cultural Materialism : The Struggle for a Science of Culture :

Some social scientists had gone as far as Comte , absorbing the general positivist doctrine wherein social science was grounded in natural science. Nevertheless, they were far from genuinely embracing E. O. Wilsons call to consilience , a form of scientific convergence wherein social science is reducible to natural science.

It is not to say that what may be regarded as classical evolutionary theory had nothing to say on the matter of cultural and personal differences, but only that such knowledge was not easily accessible, sharp or unified, leading many social scientists to regard evolution only as a useful backdrop. For in truth, throughout the 1960s and 1970s, evolution slowly enlarged its explanatory sphere to include the domains customarily reserved to the social sciences. It was during this fecund time when cooperation was explained via inclusive fitness ).

In these same progressive decades, E. O. Wilson and Robert H. MacArthur (), came Life History Theory , an evolutionary framework immediately, urgently, palpably, directly, and compellingly relevant to the social sciences and their shared mission to explain human nature and society.

Life history evolutionary theory remains obscure enough for a synopsis to be required even within some biological and evolutionary journals and books. Life history evolution is considered by some to be a sub-discipline or mid - level theory (Buss) within evolutionary biology. Beyond situating it thus, there have been many approaches to its description. Reznick (). These and other variables were found to cohere as a complex that varied along a continuum. Some organisms rush through life, investing in quantity of offspring and speed of intergenerational turnover, whereas other organisms mature, mate, and age slowly, investing in bodily maintenance and quality of offspring.

Another useful illustrative approach is to pick contrasting exemplars along the life history continuum. For these purposes, the elephant and the mouse are commonly drafted to good effect. The elephant weighs approximately two hundred pounds at birth, grows slowly, reaches sexual maturity around fourteen years, attains to an adult weight of over 10,000 pounds, has few offspring on which parental care is lavished, and is long-lived, affording substantial intergenerational overlap and interaction wherein offspring can be guarded, reared, and enculturated. By contrast, the mouse The terms r -selected and K -selected were originally applied to denote fast and slow life history strategies, respectively, early in the development of life history theory when population density was believed to be the principal driving force of life history evolution. As will be discussed in the chapters that follow, other selective pressures have partially eclipsed this early predominance of population pressure. To avoid giving the impression that we still subscribe to such early density-dependent theories, we will use the acronyms fLH to denote fast life history and sLH to denote slow life history in the prefices of the derivative expressions fLH -selected and sLH -selected. These neologisms will be used throughout the present volume as modernized substitutes for the older terms, except when quoting older sources that employed the original notation, such as the work of J. P. Rushton .