Biological determinism

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Biological determinism, also known as genetic determinism, [1] is the belief that human behaviour is directly 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. [2] Genetic reductionism is a similar concept, but it is distinct from genetic determinism in that the former refers to the level of understanding, while the latter refers to the supposedly causal role of genes. [3] Biological determinism has been associated with movements in science and society including eugenics, scientific racism, and the debates around the heritability of IQ, [4] the basis of sexual orientation, [5] and sociobiology. [6]

Contents

In 1892, the German evolutionary biologist August Weismann proposed in his germ plasm theory that heritable information is transmitted only via germ cells, which he thought contained determinants (genes). The English polymath Francis Galton, supposing that undesirable traits such as club foot and criminality were inherited, advocated eugenics, aiming to prevent supposedly defective people from breeding. The American physician Samuel George Morton and the French physician Paul Broca attempted to relate the cranial capacity (internal skull volume) to skin colour, intending to show that white people were superior. Other workers such as the American psychologists H. H. Goddard and Robert Yerkes attempted to measure people's intelligence and to show that the resulting scores were heritable, again to demonstrate the supposed superiority of people with white skin. [4]

Galton popularized the phrase nature and nurture, later often used to characterize the heated debate over whether genes or the environment determined human behaviour. Scientists such as behavioural geneticists now see it as obvious that both factors are essential, and that they are intertwined, especially through the mechanisms of epigenetics. [7] [8] The American biologist E. O. Wilson, who founded the discipline of sociobiology based on observations of animals such as social insects, controversially suggested that its explanations of social behaviour might apply to humans. [6]

History

August Weismann's 1892 germ plasm theory. The hereditary material, the germ plasm, is confined to the gonads. Somatic cells (of the body) develop afresh in each generation from the germ plasm. Weismann's Germ Plasm.svg
August Weismann's 1892 germ plasm theory. The hereditary material, the germ plasm, is confined to the gonads. Somatic cells (of the body) develop afresh in each generation from the germ plasm.

Germ plasm

In 1892, the Austrian biologist August Weismann 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 which controlled the organism. [9] 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. [10] The modern equivalent of the theory, expressed at molecular rather than cellular level, is the central dogma of molecular biology. [11]

Eugenics

The early eugenicist Francis Galton invented the term eugenics and popularized the phrase nature and nurture. Francis Galton 1850s.jpg
The early eugenicist Francis Galton invented the term eugenics and popularized the phrase nature and nurture.

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 U.S. states 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, and throughout the Western world, in the 1930s. [13] [4] [14]

Scientific racism

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. [4]

Heritability of IQ

Alfred Binet (1857–1911) designed tests specifically to measure performance, not innate ability. From the late 19th century, the American school, led by researchers such as H. H. Goddard (1866–1957), Lewis Terman (1877–1956), and Robert Yerkes (1876–1956), transformed these tests into tools for measuring inherited mental ability. They 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. [4]

Human sexual orientation

Human sexual orientation, which ranges over a continuum from exclusive attraction to the opposite sex to exclusive attraction to the same sex, [15] is caused by the interplay of genetic and environmental influences. [16] There is considerably more evidence for biological causes of sexual orientation than social factors, especially for males. [15] [17]

Sociobiology

E. O. Wilson reignited debate on biological determinism with his 1975 book Sociobiology: The New Synthesis. Plos wilson.jpg
E. O. Wilson reignited debate on biological determinism with his 1975 book Sociobiology: The New Synthesis .

Sociobiology emerged with E. O. Wilson's 1975 book Sociobiology: The New Synthesis . [6] The existence of a putative altruism gene has been debated; the evolutionary biologist W. D. Hamilton proposed "genes underlying altruism" in 1964, [18] [19] while the biologist Graham J. Thompson and colleagues identified the genes OXTR, CD38, COMT, DRD4, DRD5, IGF2, GABRB2 as candidates "affecting altruism". [20] The geneticist Steve Jones argues that altruistic behaviour like "loving our neighbour" is built into the human genome, with the proviso that neighbour means member of "our tribe", someone who shares many genes with the altruist, and that the behaviour can thus be explained by kin selection. [21] Evolutionary biologists such as Jones have argued that genes that did not lead to selfish behaviour would die out compared to genes that did, because the selfish genes would favour themselves. However, the mathematician George Constable and colleagues have argued that altruism can be an evolutionarily stable strategy, making organisms better able to survive random catastrophes. [22] [23]

Nature versus nurture debate

The belief in biological determinism was matched in the 20th century by a blank slate denial of any possible influence of genes on human behaviour, 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 are expressed within an environment, in particular that of prenatal development, and that gene expression is continuously influenced by the environment through mechanisms such as epigenetics. [24] [25] [26] Epigenetics provides evidence that human behaviours or physiology can be decided by interactions between genes and environments. [27] For example, monozygotic twins usually have exactly identical genomes. Scientists have focused on comparison studies of such twins for evaluating the heritability of genes and the roles of epigenetics in divergences and similarities between monozygotic twins, and have found that epigenetics plays an important part in human behaviours, including the stress response. [28] [29]

See also

Related Research Articles

<span class="mw-page-title-main">Heredity</span> Passing of traits to offspring from the species parents or ancestor

Heredity, also called inheritance or biological inheritance, is the passing on of traits from parents to their offspring; either through asexual reproduction or sexual reproduction, the offspring cells or organisms acquire the genetic information of their parents. Through heredity, variations between individuals can accumulate and cause species to evolve by natural selection. The study of heredity in biology is genetics.

<span class="mw-page-title-main">Pangenesis</span> Darwins proposed mechanism for heredity

Pangenesis was Charles Darwin's hypothetical mechanism for heredity, in which he proposed that each part of the body continually emitted its own type of small organic particles called gemmules that aggregated in the gonads, contributing heritable information to the gametes. He presented this 'provisional hypothesis' in his 1868 work The Variation of Animals and Plants Under Domestication, intending it to fill what he perceived as a major gap in evolutionary theory at the time. The etymology of the word comes from the Greek words pan and genesis ("birth") or genos ("origin"). Pangenesis mirrored ideas originally formulated by Hippocrates and other pre-Darwinian scientists, but using new concepts such as cell theory, explaining cell development as beginning with gemmules which were specified to be necessary for the occurrence of new growths in an organism, both in initial development and regeneration. It also accounted for regeneration and the Lamarckian concept of the inheritance of acquired characteristics, as a body part altered by the environment would produce altered gemmules. This made Pangenesis popular among the neo-Lamarckian school of evolutionary thought. This hypothesis was made effectively obsolete after the 1900 rediscovery among biologists of Gregor Mendel's theory of the particulate nature of inheritance.

<span class="mw-page-title-main">Phenotype</span> Composite of the organisms observable characteristics or traits

In genetics, the phenotype is the set of observable characteristics or traits of an organism. The term covers the organism's morphology, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code and the influence of environmental factors. Both factors may interact, further affecting the phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book The Extended Phenotype suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams as "extended phenotypes".

Sociobiology is a field of biology that aims to explain social behavior in terms of evolution. It draws from disciplines including psychology, ethology, anthropology, evolution, zoology, archaeology, and population genetics. Within the study of human societies, sociobiology is closely allied to evolutionary anthropology, human behavioral ecology, evolutionary psychology, and sociology.

Nature versus nurture is a long-standing debate in biology and society about the relative influence on human beings of their genetic inheritance (nature) and the environmental conditions of their development (nurture). The alliterative expression "nature and nurture" in English has been in use since at least the Elizabethan period and goes back to medieval French. The complementary combination of the two concepts is an ancient concept. Nature is what people think of as pre-wiring and is influenced by genetic inheritance and other biological factors. Nurture is generally taken as the influence of external factors after conception e.g. the product of exposure, experience and learning on an individual.

<span class="mw-page-title-main">August Weismann</span> German evolutionary biologist (1834–1914)

August Friedrich Leopold Weismann FRS (For), HonFRSE, LLD was a German evolutionary biologist. Fellow German Ernst Mayr ranked him as the second most notable evolutionary theorist of the 19th century, after Charles Darwin. Weismann became the Director of the Zoological Institute and the first Professor of Zoology at Freiburg.

<span class="mw-page-title-main">Central dogma of molecular biology</span> Explanation of the flow of genetic information within a biological system

The central dogma of molecular biology is an explanation of the flow of genetic information within a biological system. It is often stated as "DNA makes RNA, and RNA makes protein", although this is not its original meaning. It was first stated by Francis Crick in 1957, then published in 1958:

The Central Dogma. This states that once "information" has passed into protein it cannot get out again. In more detail, the transfer of information from nucleic acid to nucleic acid, or from nucleic acid to protein may be possible, but transfer from protein to protein, or from protein to nucleic acid is impossible. Information here means the precise determination of sequence, either of bases in the nucleic acid or of amino acid residues in the protein.

<span class="mw-page-title-main">Modern synthesis (20th century)</span> Fusion of natural selection with Mendelian inheritance

The modern synthesis was the early 20th-century synthesis of Charles Darwin's theory of evolution and Gregor Mendel's ideas on heredity into a joint mathematical framework. Julian Huxley coined the term in his 1942 book, Evolution: The Modern Synthesis. The synthesis combined the ideas of natural selection, Mendelian genetics, and population genetics. It also related the broad-scale macroevolution seen by palaeontologists to the small-scale microevolution of local populations.

<span class="mw-page-title-main">Lamarckism</span> Scientific hypothesis about inheritance

Lamarckism, also known as Lamarckian inheritance or neo-Lamarckism, is the notion that an organism can pass on to its offspring physical characteristics that the parent organism acquired through use or disuse during its lifetime. It is also called the inheritance of acquired characteristics or more recently soft inheritance. The idea is named after the French zoologist Jean-Baptiste Lamarck (1744–1829), who incorporated the classical era theory of soft inheritance into his theory of evolution as a supplement to his concept of orthogenesis, a drive towards complexity.

<span class="mw-page-title-main">Richard Lewontin</span> American evolutionary biologist and mathematician (1929–2021)

Richard Charles Lewontin was an American evolutionary biologist, mathematician, geneticist, and social commentator. A leader in developing the mathematical basis of population genetics and evolutionary theory, he applied techniques from molecular biology, such as gel electrophoresis, to questions of genetic variation and evolution.

<span class="mw-page-title-main">Weismann barrier</span> Distinction between germ cell lineages producing gametes and somatic cells

The Weismann barrier, proposed by August Weismann, is the strict distinction between the "immortal" germ cell lineages producing gametes and "disposable" somatic cells in animals, in contrast to Charles Darwin's proposed pangenesis mechanism for inheritance. In more precise terminology, hereditary information moves only from germline cells to somatic cells. This does not refer to the central dogma of molecular biology, which states that no sequential information can travel from protein to DNA or RNA, but both hypotheses relate to a gene-centric view of life.

<span class="mw-page-title-main">Group selection</span> Proposed mechanism of evolution

Group selection is a proposed mechanism of evolution in which natural selection acts at the level of the group, instead of at the level of the individual or gene.

<i>Sociobiology: The New Synthesis</i> 1975 book by biologist E. O. Wilson

Sociobiology: The New Synthesis is a book by the biologist E. O. Wilson. It helped start the sociobiology debate, one of the great scientific controversies in biology of the 20th century and part of the wider debate about evolutionary psychology and the modern synthesis of evolutionary biology. Wilson popularized the term "sociobiology" as an attempt to explain the evolutionary mechanics behind social behaviour such as altruism, aggression, and the nurturing of the young. It formed a position within the long-running nature versus nurture debate. The fundamental principle guiding sociobiology is that an organism's evolutionary success is measured by the extent to which its genes are represented in the next generation.

<span class="mw-page-title-main">Germ plasm</span> Biological concept

Germ plasm is a biological concept developed in the 19th century by the German biologist August Weismann. It states that heritable information is transmitted only by germ cells in the gonads, not by somatic cells. The related idea that information cannot pass from somatic cells to the germ line, contrary to Lamarckism, is called the Weismann barrier. To some extent this theory anticipated the development of modern genetics.

<i>Not in Our Genes</i> 1984 book by Richard Lewontin, Steven Rose, and Leon Kamin

Not in Our Genes: Biology, Ideology and Human Nature is a 1984 book by the evolutionary geneticist Richard Lewontin, the neurobiologist Steven Rose, and the psychologist Leon Kamin, in which the authors criticize sociobiology and genetic determinism and advocate a socialist society. Its themes include the relationship between biology and society, the nature versus nurture debate, and the intersection of science and ideology.

Hereditarianism is the doctrine or school of thought that heredity plays a significant role in determining human nature and character traits, such as intelligence and personality. Hereditarians believe in the power of genetics to explain human character traits and solve human social and political problems. Hereditarians adopt the view that an understanding of human evolution can extend the understanding of human nature.

In ecology and genetics, a reaction norm, also called a norm of reaction, describes the pattern of phenotypic expression of a single genotype across a range of environments. One use of reaction norms is in describing how different species—especially related species—respond to varying environments. But differing genotypes within a single species may also show differing reaction norms relative to a particular phenotypic trait and environment variable. For every genotype, phenotypic trait, and environmental variable, a different reaction norm can exist; in other words, an enormous complexity can exist in the interrelationships between genetic and environmental factors in determining traits. The concept was introduced by Richard Woltereck in 1909.

Behavioural genetics, also referred to as behaviour genetics, is a field of scientific research that uses genetic methods to investigate the nature and origins of individual differences in behaviour. While the name "behavioural genetics" connotes a focus on genetic influences, the field broadly investigates the extent to which genetic and environmental factors influence individual differences, and the development of research designs that can remove the confounding of genes and environment. Behavioural genetics was founded as a scientific discipline by Francis Galton in the late 19th century, only to be discredited through association with eugenics movements before and during World War II. In the latter half of the 20th century, the field saw renewed prominence with research on inheritance of behaviour and mental illness in humans, as well as research on genetically informative model organisms through selective breeding and crosses. In the late 20th and early 21st centuries, technological advances in molecular genetics made it possible to measure and modify the genome directly. This led to major advances in model organism research and in human studies, leading to new scientific discoveries.

Epigenetics is the study of changes in gene expression that occur via mechanisms such as DNA methylation, histone acetylation, and microRNA modification. When these epigenetic changes are heritable, they can influence evolution. Current research indicates that epigenetics has influenced evolution in a number of organisms, including plants and animals.

Inclusive fitness in humans is the application of inclusive fitness theory to human social behaviour, relationships and cooperation.

References

  1. ↑ de Melo‐Martín, Inmaculada (2003). "When Is Biology Destiny? Biological Determinism and Social Responsibility". Philosophy of Science . 70 (5): 1184–1194. doi:10.1086/377399. JSTOR   10.1086/377399. S2CID   224834276. 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.
  2. ↑ "Biological determinism". Oxford Reference. 2021. Retrieved 26 September 2021. The idea that an individual's personality or behaviour is caused by their particular genetic endowment, rather than by social or cultural factors—by nature rather than nurture.
  3. ↑ Hayes, Nicky; Stratton, Peter (2017). A Student's Dictionary of Psychology and Neuroscience. Routledge. p. 138. ISBN   978-1351803199.
  4. 1 2 3 4 5 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. doi:10.1007/bf00397505. JSTOR   4330882. PMID   11611452. S2CID   29672121.
  5. ↑ Lewontin, Richard; Rose, Steven; Kamin, Leon (1984). Not in Our Genes: Biology, Ideology and Human Nature. Pantheon Books. pp.  131–163.
  6. 1 2 3 May, Robert M. (1 April 1976). "Sociobiology: a new synthesis and an old quarrel". Nature . 260 (5550): 390–392. Bibcode:1976Natur.260..390M. doi: 10.1038/260390a0 . PMID   11643303. S2CID   4144395.
  7. ↑ Powledge, Tabitha M. (2011). "Behavioral Epigenetics: How Nurture Shapes Nature". BioScience . 61 (8): 588–592. doi: 10.1525/bio.2011.61.8.4 .
  8. ↑ Moore, David S. (2003). The Dependent Gene: The Fallacy of Nature Vs. Nurture. Henry Holt. ISBN   978-0-8050-7280-8.
  9. ↑ Weismann, August (1892). Das Keimplasma: eine Theorie der Vererbung [The Germ Plasm: A Theory of Inheritance] (in German). Jena: S. Fischer Verlag.
  10. ↑ Huxley, Julian (1942). Evolution, the modern synthesis. Allen and Unwin. p.  17.
  11. ↑ Turner, J. Scott (2013). Henning, Brian G.; Scarfe, Adam Christian (eds.). Biology's Second Law: Homeostasis, Purpose, and Desire. Rowman & 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.{{cite book}}: |work= ignored (help)
  12. ↑ Galton, Francis (1874). "On men of science, their nature and their nurture". Proceedings of the Royal Institution of Great Britain . 7: 227–236.
  13. ↑ Allen, Garland Edward (9 December 2015). "Biological determinism". Encyclopædia Britannica.
  14. ↑ Gould, Stephen Jay (1981). The Mismeasure of Man . W. W. Norton.
  15. 1 2 Frankowski, B. L.; American Academy of Pediatrics Committee on Adolescence (June 2004). "Sexual orientation and adolescents". Pediatrics . 113 (6): 1827–1832. doi: 10.1542/peds.113.6.1827 . PMID   15173519.
  16. ↑ Stuart, Gail Wiscarz (2014). Principles and Practice of Psychiatric Nursing. Elsevier. p. 502. ISBN   978-0-323-29412-6.
  17. ↑ Bailey, J. M.; Vasey, P. L.; Diamond, L. M.; et al. (2016). "Sexual Orientation, Controversy, and Science". Psychological Science in the Public Interest . 17 (21): 45–101. doi: 10.1177/1529100616637616 . PMID   27113562.
  18. ↑ Hamilton, W. D. (1964). "The genetical evolution of social behaviour. I". Journal of Theoretical Biology . 7 (1): 1–16. Bibcode:1964JThBi...7....1H. doi:10.1016/0022-5193(64)90038-4. PMID   5875341.
  19. ↑ Hamilton, W. D. (1964). "The genetical evolution of social behaviour. II". Journal of Theoretical Biology . 7 (1): 17–52. Bibcode:1964JThBi...7...17H. doi:10.1016/0022-5193(64)90039-6. PMID   5875340.
  20. ↑ Thompson, G. J.; Hurd, P. L.; Crespi, B. J. (2013). "Genes underlying altruism". Biology Letters . 9 (6): 20130395. doi:10.1098/rsbl.2013.0395. PMC   3871336 . PMID   24132092.
  21. ↑ Giberson, Karl (15 August 2014). "Book review: 'The Serpent's Promise', on Bible-Science tensions, by Steve Jones". The Washington Post . Retrieved 9 June 2018.
  22. ↑ Johnston, Ian (21 July 2016). "Altruism has more of an evolutionary advantage than selfishness, mathematicians say". The Independent .
  23. ↑ Constable, George W. A.; Rogers, Tim; McKane, Alan J.; Tarnita, Corina E. (22 July 2016). "Demographic noise can reverse the direction of deterministic selection". Proceedings of the National Academy of Sciences . 113 (32): E4745–E4754. arXiv: 1608.03471 . doi: 10.1073/pnas.1603693113 . PMC   4987790 . PMID   27450085.
  24. ↑ Ridley, Matt (2003). Nature via Nurture: Genes, Experience, & What Makes Us Human. HarperCollins. ISBN   978-0-002-00663-7.
  25. ↑ Moore, David S. (2015). The Developing Genome: An Introduction to behavioural Epigenetics (1st ed.). Oxford University Press. ISBN   978-0-199-92234-5.
  26. ↑ Gutiérrez, Luci (January 24, 2014). "Time to Retire The Simplicity of Nature vs. Nurture". The Wall Street Journal .
  27. ↑ Berger, Shelley L.; Kouzarides, Tony; Shiekhattar, Ramin; Shilatifard, Ali (1 April 2009). "An operational definition of epigenetics". Genes & Development. 23 (7): 781–783. doi:10.1101/gad.1787609. PMC   3959995 . PMID   19339683.
  28. ↑ Petronis, Arturas (1 July 2006). "Epigenetics and twins: three variations on the theme". Trends in Genetics . 22 (7): 347–350. doi:10.1016/j.tig.2006.04.010. PMID   16697072.
  29. ↑ Bell, Jordana T.; Spector, Tim D. (1 March 2011). "A twin approach to unraveling epigenetics". Trends in Genetics. 27 (3): 116–125. doi:10.1016/j.tig.2010.12.005. PMC   3063335 . PMID   21257220.
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