Biological Determinism: Definition and Examples

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Biological determinism is the idea that an individual’s characteristics and behavior are dictated by some aspect of biology, like genes. Biological determinists believe environmental factors have no influence on a person. According to biological determinists, social categories like gender, race, sexuality, and disability are based on biology and this justifies the oppression and control of specific groups of people.

This perspective implies that an individual's path in life is determined from birth, and therefore, that we lack free will.

Key Takeaways: Biological Determinism

  • Biological determinism is the idea that biological attributes, such as one’s genes, dictate one’s destiny, and environmental, social, and cultural factors play no role in shaping an individual.
  • Biological determinism has been used to uphold white supremacy and justify racial, gender, and sexual discrimination as well as other biases against various groups of people.
  • Although the theory has been scientifically discredited, the idea that differences between people are based in biology still persists in various forms.

Biological Determinism Definition

Biological determinism (also referred to as biologism, biodeterminism, or genetic determinism) is the theory that an individual's characteristics and behavior are determined exclusively by biological factors. In addition, environmental, social, and cultural factors do not play a role in shaping an individual, according to the theory.

Biological determinism implies that the divergent circumstances of various groups in society, including those from different races, classes, genders, and sexual orientations, are inborn and predetermined by biology. As a result, biological determinism has been used to justify white supremacy, gender discrimination, and other biases against groups of people.

Today, biological determinism has been scientifically discredited. In his 1981 book refuting biological determinism, The Mismeasure of Man, evolutionary biologist Stephen Jay Gould asserted that the researchers who found evidence for biological determinism were most likely influenced by their own biases.

Yet, biological determinism still rears its head in current debates about hot button issues like racial categorization, sexual orientation, gender equality, and immigration. And many scholars continue to uphold biological determinism to advance ideas about intelligence, human aggression, and racial, ethnic, and gender differences.


The roots of biological determinism stretch back to ancient times. In Politics, Greek philosopher Aristotle (384-322 BCE) claimed that the distinction between rulers and the ruled is evident at birth. It wasn’t until the eighteenth century, however, that biological determinism became more prominent, especially among those who wished to justify unequal treatment of different racial groups. The first to divide and categorize the human race was Swedish scientist Carolus Linnaeus in 1735, and many others soon followed the trend.

At the time, assertions of biological determinism were mainly based on ideas about heredity. However, the tools needed to directly study heredity were not yet available, so physical features, like facial angle and cranium ratio, were instead associated with various internal traits. For example, in the 1839 study Crania Americana, Samuel Morton studied over 800 skulls in an attempt to prove the "natural superiority" of Caucasians over other races. This research, which sought to establish racial hierarchy in the nineteenth and early twentieth century, has since been debunked.

However, some scientific findings continued to be manipulated to support assertions about racial differences, such as Charles Darwin's ideas about natural selection. While Darwin did at one point reference “civilized” and “savage” races in On the Origin of Species, it was not a major part of his argument that natural selection led to the differentiation of humans from other animals. Yet, his ideas were used as the basis for social Darwinism, which argued that natural selection was taking place among the different human races, and that “survival of the fittest” justified racial segregation and white superiority. Such thinking was used to support racist policies, which were viewed as a simple extension of natural law.

By the beginning of the twentieth century, biological determinism reduced any traits that were undesirable to faulty genes. These included both physical conditions, such as cleft palate and clubfoot, as well as socially unacceptable behaviors and psychological issues, like criminality, intellectual disability, and bipolar disorder.


No overview of biological determinism would be complete without discussing one of its most well-known movements: eugenics. Francis Galton, a British naturalist, originated the term in 1883. Like the social Darwinists, his ideas were influenced by the theory of natural selection. Yet, while social Darwinists were willing to wait for survival of the fittest to do its work, eugenicists wanted to push the process along. For example, Galton championed planned breeding among "desirable" races and preventing breeding among "less desirable" races.

Eugenicists believed that the spread of genetic "defects," especially intellectual disabilities, was responsible for all social ills. In the 1920s and 1930s, the movement used IQ tests to sort people into intellectual categories, with those scoring even slightly below average being labeled genetically disabled.

Eugenics was so successful that, in the 1920s, American states began to adopt sterilization laws. Eventually, more than half of the states had a sterilization law on the books. These laws mandated that people who were pronounced "genetically unfit" in institutions must be subjected to mandatory sterilization. By the 1970s, thousands of American citizens had been involuntarily sterilized. Those in other countries were subjected to similar treatment.

Heritability of IQ

While eugenics is now criticized on moral and ethical grounds, the interest in creating a link between intelligence and biological determinism persists. For example, in 2013, the genomes of highly intelligent individuals were being studied in China as a means to determine the genetic basis for intelligence. The idea behind the study was that intelligence must be inherited and, therefore, established at birth.

Yet, no scientific studies have shown that specific genes result in a specific degree of intelligence. In fact, when a relationship between genes and IQ has been demonstrated, the effect is limited to just an IQ point or two. On the other hand, one’s environment, including educational quality, has been shown to influence IQ by 10 or more points.


Biological determinism has also been applied to ideas about sex and gender, particularly as a way to deny specific rights to women. For instance, in 1889, Patrick Geddes and J. Arthur Thompson claimed that metabolic state was the source of various traits in men and women. Women were said to conserve energy, while men expend energy. As a result, women are passive, conservative, and lack interest in politics, whereas men are the opposite. These biological “facts” were used to prevent the extension of political rights to women.