Biological determinism or genetic determinism is the belief that human behavior is controlled by an individual's genes or some component of their physiology, generally at the expense of the role of the environment, whether in embryonic development or in learning. It has been associated with movements in science and society including eugenics, scientific racism, the supposed heritability of IQ, the supposed biological basis for gender roles, and the sociobiology debate. A pioneer of eugenics, Francis Galton, popularized the phrase nature and nurture, later often used to characterize the heated debate over whether genes or the environment determined human behavior. Many scientists now see it as obvious that both factors are essential, and that they are intertwined.
Biological determinism owes its origins to the Austrian biologist August Weismann. In 1892, he proposed that multicellular organisms consist of two separate types of cell: somatic cells which carry out the body's ordinary functions, and germ cells which transmit heritable information. He called the material that carried the information, now identified as DNA, the germ plasm, and individual components of it, now called genes, determinants. Weismann argued that there is a one-way transfer of information from the germ cells to somatic cells, so that nothing acquired by the body during an organism's life can affect the germ plasm and the next generation. This effectively denied that Lamarckism (inheritance of acquired characteristics) was a possible mechanism of evolution. The modern equivalent of the theory, expressed at molecular rather than cellular level, is the central dogma of molecular biology.
Early ideas of biological determinism centred on the inheritance of undesirable traits, whether physical such as club foot or cleft palate, or psychological such as alcoholism, bipolar disorder and criminality. The belief that such traits were inherited led to the desire to solve the problem with the eugenics movement, led by a follower of Darwin, Francis Galton (1822–1911), by forcibly reducing breeding by supposedly defective people. By the 1920s, many states in America brought in laws permitting the compulsory sterilization of people considered genetically unfit, including inmates of prisons and psychiatric hospitals. This was followed by similar laws in Germany in the 1930s.
Under the influence of determinist beliefs, the American craniologist Samuel George Morton (1799–1851), and later the French anthropologist Paul Broca (1824–1880), attempted to measure the cranial capacities (internal skull volumes) of people of different skin colours, intending to show that whites were superior to the rest, with larger brains. All the supposed proofs from such studies were invalidated by methodological flaws. The results were used to justify slavery, and to oppose women's suffrage.
Heritability of IQ
From the late 19th century, workers such as Alfred Binet (1857–1911), H. H. Goddard (1866–1957), Lewis Terman (1877–1956), and Robert Yerkes (1876–1956) attempted to measure people's intelligence with IQ tests, to demonstrate that the resulting scores were heritable, and so to conclude that people with white skin were superior to the rest. It proved impossible to design culture-independent tests and to carry out testing in a fair way given that people came from different backgrounds, or were newly-arrived immigrants, or were illiterate. The results were used to oppose immigration of people from southern and eastern Europe to America.
Human gender roles
Lynda Birke argues in her 1992 book In Pursuit of Difference that biology explains sexual differences by the mechanisms of chromosomes, genetics, and inheritance. However, hormonal differences are not absolute, and people can be born with intersex characteristics, for example as a genetic mosaic. Homosexuality can be attributed to both biological and social causes. Dean Hamer has studied the so-called "gay gene". The neuroscientist Simon LeVay in 1991 studied the difference in hypothalamic structures between homosexual and heterosexual men, finding that the INAH-3 suggested a partial cause for homosexuality. Richard Lewontin, Steven Rose, and Leon Kamin's book Not in Our Genes discussed a study of girls who were relatively "masculinized". The biologists John Money and Anke Ehrhardt looked for ways to describe femininity that fitted their own social standards, such as clothing preference or using makeup. The experiment, in Lewontin's words, "ignores the existence of societies in which women wear pants, or in which men wear skirts, or in which men enjoy and appropriate jewelry to themselves." Gender differences in work are becoming less pronounced, suggesting that these are imposed by society. In contrast, the standard model of sex and gender indicates a clear-cut dichotomy between males and females, with no overlap, a cultural model followed by professionals such as doctors when they deal with gender assignment.
Sociobiology emerged with E. O. Wilson's 1975 book Sociobiology: The New Synthesis. The existence of a putative altruism gene is debated. Kaplan and Rogers claim "Most sociobiologists agree that no such gene could exist for so long in a population as it would soon be lost because it would not compete successfully against the 'selfish' genes", and argue that "Genes and environment are not discrete opposites; they are both entirely integrated aspects of the developmental process." Consequently, genes can't be "selfish", as "genes are expressed as biochemical processes; behavior is expressed by the whole organism."
Nature versus nurture debate
The belief in biological determinism has been matched by a blank slate denial of any possible influence of genes on human behavior, leading to a long and heated debate about "nature and nurture". By the 21st century, many scientists had come to feel that the dichotomy made no sense. They noted that genes were expressed within an environment, in particular that of prenatal development, and that genes were continuously controlled by the environment through mechanisms such as epigenetics.
- Behavioral epigenetics
- Behavioral genetics
- Dual inheritance theory
- Genetic fallacy
- Nature–culture divide
- Social determinism
- de Melo‐Martín, Inmaculada (December 2003). "When Is Biology Destiny? Biological Determinism and Social Responsibility" (PDF). Philosophy of Science. 70 (5): 1184–1194.
I will use here 'biology' and 'genetics' ... interchangeably ... because this is the way they are used in most of the literature I analyze here ... Critics accuse those who use biology to explain every possible human trait of presupposing the truth of biological or genetic determinism.
- Feminist Frontiers, Ninth Edition, by Taylor, Whittier, and Rupp; How Societies Work, Fourth Edition, by Joanne Naiman
- Weismann, August (1892). Das Keimplasma: eine Theorie der Vererbung [The Germ Plasm: A Theory of Inheritance] (in German). Jena: Fischer.
- Huxley, Julian (1942). Evolution, the modern synthesis. Allen and Unwin. p. 17.
- Turner, J. Scott (2013). Henning, Brian G.; Scarfe, Adam Christian, ed. Biology's Second Law: Homeostasis, Purpose, and Desire. Beyond Mechanism: Putting Life Back Into Biology. Rowman and Littlefield. p. 192. ISBN 978-0-7391-7436-4.
Where Weismann would say that it is impossible for changes acquired during an organism's lifetime to feed back onto transmissible traits in the germ line, the CDMB now added that it was impossible for information encoded in proteins to feed back and affect genetic information in any form whatsoever, which was essentially a molecular recasting of the Weismann barrier.
- Galton, Francis (1874). "On men of science, their nature and their nurture". Proceedings of the Royal Institution of Great Britain. 7: 227–236.
- Allen, Garland Edward (9 December 2015). "Biological determinism". Encyclopædia Britannica.
- Allen, Garland E. (1984). "The Roots of Biological Determinism: review of The Mismeasure of Man by Stephen Jay Gould". Journal of the History of Biology. 17 (1): 141–145. JSTOR 4330882.
- Gould, Stephen Jay (1981). The Mismeasure of Man. W. W. Norton.
- In Pursuit of Difference by Lynda Birke, 1992
- Laurie, Timothy (3 June 2015), Bigotry or biology: the hard choice for an opponent of marriage equality, The Drum
- Intersex Society of North America
- Paul R. Abramson, ed. (1995). Sexual Nature/Sexual Culture (1 ed.). University Of Chicago Press. p. 4. ISBN 0226001822.
- Brookey, Robert Alan (2001). "Bio-Rhetoric, Background Beliefs, and the Biology of Homosexuality". Argumentation and Advocacy. 37 (4).
- Spanier, Bonnie (1995). "Biological Determinism and Homosexuality". NWSA Journal. 7 (1): 54–71.
- Nimmons, David (March 1994). "Sex and the Brain". Discover Magazine.
- Lewontin, Richard, Steven Rose, and Leon Kamin. Not in Our Genes: Biology, Ideology and Human Nature. New York: Pantheon Books, 1984. "The Determined Patriarchy", Chapter 6, pp. 131–163
- Fausto-Sterling, Anne, "Of Gender and Genitals" in Sexing the Body, Of Gender and Genitals, Basic Books, 2000, pp. 44–77
- Gisela Kaplan & Lesley J. Rogers, Race and Gender Fallacies, Routledge, 2001[page needed]
- Ridley, M. (2003). Nature via Nurture: Genes, Experience, & What Makes Us Human. Harper Collins. ISBN 0-002-00663-4.
- Moore, David S. (2015). The Developing Genome: An Introduction to Behavioral Epigenetics (1st ed.). Oxford University Press. ISBN 978-0-199-92234-5.
- Gutiérrez, Luci (January 24, 2014). "Time to Retire The Simplicity of Nature vs. Nurture". Wall Street Journal.