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Sociobiology is a field of scientific study which is based on the assumption that social behavior has resulted from evolution and attempts to explain and examine social behavior within that context. Often considered a branch of biology and sociology, it also draws from ethology, anthropology, evolution, zoology, archaeology, population genetics, and other disciplines. Within the study of human societies, sociobiology is very closely allied to the fields of Darwinian anthropology, human behavioral ecology and evolutionary psychology.
Sociobiology investigates social behaviors, such as mating patterns, territorial fights, pack hunting, and the hive society of social insects. It argues that just as selection pressure led to animals evolving useful ways of interacting with the natural environment, it led to the genetic evolution of advantageous social behavior.
While the term "sociobiology" can be traced to the 1940s, the concept didn't gain major recognition until 1975 with the publication of Edward O. Wilson's book, Sociobiology: The New Synthesis. The new field quickly became the subject of heated controversy. Criticism, most notably made by Richard Lewontin and Stephen Jay Gould, centered on sociobiology's contention that genes play an ultimate role in human behavior and that traits such as aggressiveness can be explained by biology rather than a person's social environment. Sociobiologists generally responded to the criticism by pointing to the complex relationship between nature and nurture. In response to some of the potentially fractious implications sociobiology had on human biodiversity, anthropologist John Tooby and psychologist Leda Cosmides founded the field of evolutionary psychology.
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E.O. Wilson defines sociobiology as: “The extension of population biology and evolutionary theory to social organization”[1]
Sociobiology is based on the premise that some behaviors (both social and individual) are at least partly inherited and can be affected by natural selection. It begins with the idea that behaviors have evolved over time, similar to the way that physical traits are thought to have evolved. It predicts therefore that animals will act in ways that have proven to be evolutionarily successful over time, which can among other things result in the formation of complex social processes conducive to evolutionary fitness.
The discipline seeks to explain behavior as a product of natural selection. Behavior is therefore seen as an effort to preserve one's genes in the population. Inherent in sociobiological reasoning is the idea that certain genes or gene combinations that influence particular behavioral traits can be inherited from generation to generation
For example, newly dominant male lions often will kill cubs in the pride that were not sired by them. This behaviour is adaptive in evolutionary terms because killing the cubs eliminates competition for their own offspring and causes the nursing females to come into heat faster, thus allowing more of his genes to enter into the population. Sociobiologists would view this instinctual cub-killing behavior as being inherited through the genes of successfully reproducing male lions, whereas non-killing behaviour may have "died out" as those lions were less successful in reproducing.
Genetic mouse mutants have now been harnessed to illustrate the power that genes exert on behaviour. For example, the transcription factor FEV (aka Pet1) has been shown, through its role in maintaining the serotonergic system in the brain, to be required for normal aggressive and anxiety-like behavior.[2] Thus, when FEV is genetically deleted from the mouse genome, male mice will instantly attack other males, whereas their wild-type counterparts take significantly longer to initiate violent behaviour. In addition, FEV has been shown to be required for correct maternal behaviour in mice, such that their offspring do not survive unless cross-fostered to other wild-type female mice.[3]
A genetic basis for instinctive behavioural traits among non-human species, such as in the above example, is commonly accepted among many biologists; however, attempting to use a genetic basis to explain complex behaviours in human societies has remained extremely controversial.
According to the OED, John Paul Scott coined the word "sociobiology" at a 1946 conference on genetics and social behaviour, and became widely used after it was popularized by Edward O. Wilson in his 1975 book, Sociobiology: The New Synthesis. However, the influence of evolution on behavior has been of interest to biologists and philosophers since soon after the discovery of evolution itself. Peter Kropotkin's Mutual Aid: A Factor of Evolution, written in the early 1890s, is a popular example. Antecedents of modern sociobiological thinking can be traced to the 1960s and the work of such biologists as Richard D. Alexander, Robert Trivers and William D. Hamilton.
Nonetheless, it was Wilson's book that pioneered and popularized the attempt to explain the evolutionary mechanics behind social behaviors such as altruism, aggression, and nurturence, primarily in ants (Wilson's own research specialty) but also in other animals (bees, wasps and termites).[4] The final chapter of the book is devoted to sociobiological explanations of human behavior, and Wilson later wrote a Pulitzer Prize winning book, On Human Nature, that addressed human behavior specifically.
Edward H. Hagen writes in The Handbook of Evolutionary Psychology that sociobiology is, despite the public controversy regarding the applications to humans, "one of the scientific triumphs of the twentieth century." "Sociobiology is now part of the core research and curriculum of virtually all biology departments, and it is a foundation of the work of almost all field biologists" Sociobiological research on nonhuman organisms has increased dramatically and appears continuously in the world's top scientific journals such as Nature and Science.The more general term behavioral ecology is commonly used as substitute for the term sociobiology in order to avoid the public controversy.[5]
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Sociobiologists believe that human behavior, as well as nonhuman animal behavior, can be partly explained as the outcome of natural selection. They contend that in order to fully understand behavior, it must be analyzed in terms of evolutionary considerations.
Natural selection is fundamental to evolutionary theory. Variants of hereditary traits which increase an organism's ability to survive and reproduce will be more greatly represented in subsequent generations, i.e., they will be "selected for". Thus, inherited behavioral mechanisms that allowed an organism a greater chance of surviving and/or reproducing in the past are more likely to survive in present organisms. That inherited adaptive behaviors are present in nonhuman animal species has been multiply demonstrated by biologists, and it has become a foundation of evolutionary biology. However, there is continued resistance by some researchers over the application of evolutionary models to humans, particularly from within the social sciences, where culture has long been assumed to be the predominant driver of behavior.
Sociobiology is based upon two fundamental premises:
Sociobiology uses Nikolaas Tinbergen's four categories of questions and explanations of animal behavior. Two categories are at the species level; two, at the individual level. The species-level categories (often called “ultimate explanations”) are
The individual-level categories (often called “proximate explanations”) are
Sociobiologists are interested in how behavior can be explained logically as a result of selective pressures in the history of a species. Thus, they are often interested in instinctive, or intuitive behavior, and in explaining the similarities, rather than the differences, between cultures. For example, mothers within many species of mammals – including humans – are very protective of their offspring. Sociobiologists reason that this protective behavior likely evolved over time because it helped those individuals which had the characteristic to survive and reproduce. Over time, individuals who exhibited such protective behaviours would have had more surviving offspring than did those who did not display such behaviours, such that this parental protection would increase in frequency in the population. In this way, the social behavior is believed to have evolved in a fashion similar to other types of nonbehavioral adaptations, such as (for example) fur or the sense of smell.
Individual genetic advantage often fails to explain certain social behaviors as a result of gene-centred selection, and evolution may also act upon groups. The mechanisms responsible for group selection employ paradigms and population statistics borrowed from game theory. E.O. Wilson argued that altruistic individuals must reproduce their own altruistic genetic traits for altruism to survive. When altruists lavish their resources on non-altruists at the expense of their own kind, the altruists tend to die out and the others tend to grow. In other words, altruism is more likely to survive if altruists practice the ethic that "charity begins at home."Altruism is defined as "a concern for the welfare of others." An extreme example of altruism involves a soldier risking his life to help a fellow soldier. This example raises questions about how altruistic genes can be passed on if this soldier dies without having any children to exhibit the same altruistic traits.[6]
Within sociobiology, a social behavior is first explained as a sociobiological hypothesis by finding an evolutionarily stable strategy that matches the observed behavior. Stability of a strategy can be difficult to prove, but usually, a well-formed strategy will predict gene frequencies. The hypothesis can be supported by establishing a correlation between the gene frequencies predicted by the strategy, and those expressed in a population. However, such an approach can be methodologically problematic, as a statistical correlation could be due to circularity if the measurement of gene frequency indirectly uses the same measurements that describe the strategy.
Altruism between social insects and littermates has been explained in such a way. Altruistic behavior, behavior that increases the reproductive fitness of others at the apparent expense of the altruist,[7] in some animals has been correlated to the degree of genome shared between altruistic individuals. A quantitative description of infanticide by male harem-mating animals when the alpha male is displaced as well as rodent female infanticide and fetal resorption are active areas of study. In general, females with more bearing opportunities may value offspring less, and may also arrange bearing opportunities to maximize the food and protection from mates.
An important concept in sociobiology is that temperamental traits within a gene pool and between gene pools exist in an ecological balance. Just as an expansion of a sheep population might encourage the expansion of a wolf population, an expansion of altruistic traits within a gene pool may also encourage the expansion of individuals with dependent traits.
Sociobiology is sometimes associated with arguments over the "genetic" basis of intelligence. While sociobiology is predicated on the observation that genes do affect behavior, it is perfectly consistent to be a sociobiologist while arguing that measured IQ variations between individuals reflect mainly cultural or economic rather than genetic factors. However, many critics point out that the usefulness of sociobiology as an explanatory tool breaks down once a trait is so variable as to no longer be exposed to selective pressures. In order to explain aspects of human intelligence as the outcome of selective pressures, it must be demonstrated that those aspects are inherited, or genetic, but this does not necessarily imply differences among individuals: a common genetic inheritance could be shared by all humans, just as the genes responsible for number of limbs are shared by all individuals.
Researchers performing twin studies have argued that differences between people on behavioral traits such as creativity, extroversion and aggressiveness are between 45% to 75% due to genetic differences, and intelligence is said by some to be about 80% genetic after one matures (discussed at Intelligence quotient#Shared_family_environment).
Criminality is actively under study, but extremely controversial. There are arguments that in some environments criminal behavior might be adaptive.[8]
Sociobiology differs in some ways from evolutionary psychology. Evolutionary psychology studies the animal nervous system from an evolutionary perspective including aspects not necessarily related to social behavior such as vision and navigation. Sociobiology is restricted to the biology of social behavior but also including organisms like plants. Evolutionary psychologists include the neural mechanisms that cause behavior in the research while sociobiologists often only study behavior. Evolutionary psychology emphasize that for humans the neural mechanisms evolved in an ancestral environment that differed from the current environment while animal sociobiologists look at animal adaptions to the current environment.[5]
Many critics draw an intellectual link between sociobiology and biological determinism, the belief that most human differences can be traced to specific genes rather than differences in culture or social environments. Critics also draw parallels between biological determinism as an underlying philosophy to the social Darwinian and eugenics movements of the early 20th century, and controversies in the history of intelligence testing. Steven Pinker argues that critics have been overly swayed by politics and a "fear" of biological determinism.[9] However, all these critics have claimed that sociobiology fails on scientific grounds, independent of their political critiques. In particular, Lewontin, Rose & Kamin drew a detailed distinction between the politics and history of an idea and its scientific validity,[10] as has Stephen Jay Gould.[11]
Wilson and his supporters counter the intellectual link by denying that Wilson had a political agenda, still less a right-wing one. They pointed out that Wilson had personally adopted a number of liberal political stances and had attracted progressive sympathy for his outspoken environmentalism. They argued that as scientists they had a duty to uncover the truth whether that was politically correct or not. They argued that sociobiology does not necessarily lead to any particular political ideology as many critics implied. Many subsequent sociobiologists, including Robert Wright, Anne Campbell, Frans de Waal and Sarah Blaffer Hrdy, have used sociobiology to argue quite separate points. Noam Chomsky came to the defense of sociobiology's methodology, noting that it was the same methodology he used in his work on linguistics. However, he roundly criticized the sociobiologists' actual conclusions about humans as lacking substance. He also noted that the anarchist Peter Kropotkin had made similar arguments in his book Mutual Aid: A Factor of Evolution, although focusing more on altruism than aggression, suggesting that anarchist societies were feasible because of an innate human tendency to cooperate.[12]
Wilson's claims that he had never meant to imply what ought to be, only what is the case are supported by his writings, which are descriptive, not prescriptive. However, some critics have argued that the language of sociobiology sometimes slips from "is" to "ought",[10] leading sociobiologists to make arguments against social reform on the basis that socially progressive societies are at odds with our innermost nature. Views such as this, however, are often criticized as examples of the naturalistic fallacy, when reasoning jumps from descriptions about what is to prescriptions about what ought to be. (A common example is the justification of militarism if scientific evidence showed warfare was part of human nature.) It has also been argued that opposition to stances considered anti-social, such as ethnic nepotism, are based on moral assumptions, not bioscientific assumptions, meaning that it is not vulnerable to being disproved by bioscientific advances.[9]:145 The history of this debate, and others related to it, are covered in detail by Cronin (1992), Segerstråle (2000), Alcock (2001),[13][14][15] and most recently by Griffith (2011).[16]
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