Question

Why and how was the theory of biological determinism used in the past?

Answer 1

Biological determinism, also known as genetic determinism, is the belief that an individual's genes or some component of their physiology directly control their behavior, generally at the expense of the role of the environment, whether in embryonic development or in learning.

Complete answer:
One of the great questions to which humanity has sought an answer is "Why do we behave the way we do? What causes us to think and feel the way we do?"

Nature and Nurture are two opposing theories that have been summarized. Nature refers to what we have inside of us in terms of DNA and other physical traits that we inherit from our parents and pass down to our children.Nurture refers to learned behaviors - that we begin with a blank slate and our behaviors and beliefs are shaped by what we learn from others.The Nature side of the debate is the Biological Determinism side, which holds that who we are is determined by biology.

It has been used to try to understand the body and the brain: the body as a machine, the brain as a computer, and so on. It has also been used to justify discrimination against various races and both sexes, with the idea being that race/sex x has a tendency to be smarter/dumber, better athletes/worse athletes, more likely to commit crime, more emotional, less rational, and so on, and that these tendencies, being written in the DNA, was an unchangeable fact about a race.

With the discovery that the brain constantly rewires itself (known as Brain Plasticity) and that experiences can cause the body to recode the DNA through the epigenome (here's an article that explains it well), Biological Determinism no longer holds as much sway as it once did.

Note: Genetic reductionism is a similar concept to genetic determinism, but it differs in that the former refers to the level of understanding, whereas the latter refers to the allegedly causal role of genes. Biological determinism has been linked to movements in science and society such as eugenics, scientific racism, and debates over the heritability of intelligence and the basis of sexual orientation,and sociobiology.