Is psychology not the study of behaviour? Many scientists want to understand why we do, think, and feel.
To understand behaviour, we must remember its roots. This is genetic inheritance, the product of species evolution. Here, hereditary behaviour patterns are examined.
How does genetics affect behaviour?
Although the environment shapes behaviour, genetics shape personality, emotions, and specific behaviours.
Genetic and twin studies have produced the most research relating genes to intellect and impulsivity. Depression, addictions, and autism have hereditary predispositions.
An developing field is epigenetics, which studies how the environment affects gene expression. Changes would also be inherited. Thus, it offers a novel approach to studying genetic inheritance and environmental influence. This shows how stress or toxins affect behaviour.
Hereditary behaviour?
Hereditary behaviour is genetically based and passed down from generation to generation. Examples include social interaction patterns. Along with personality features and addiction patterns.
Hereditary behaviours?
Many behaviours, traits, and preferences are genetically based, despite appearances. Check out the ones below:
Addictive behaviour: some persons are more prone to substance or gambling addictions.
Intelligence: many genes determine cognitive ability. A nice overview of this Molecular Psychiatry study will satiate your curiosity.
According to a Frontiers in Behavioural Neuroscience study, aggression is also inherited. As previously mentioned, epigenetics regulates gene expression.
An article in Translational Psychiatry states that the Big Five model of personality traits estimates that genetic inheritance explains 40–60% of behaviours. It is unclear which genes cause this variance.
Genetics affect mood disorders including depression and bipolarity. “People with major depressive disorder are three times more likely than those without major depressive disorder to have a first-degree relative who also suffers from depression,” Eric Dunn et al. (2015) stated.
Not everything is a gene: inheritance models
Genes do not cause behaviours or dispositions. Most behaviours come from many gene interactions, while some follow a Mendelian inheritance model. Naturally, environmental considerations must be considered.
These genes are found by genome-wide investigations. A person's genetic variations and behaviours are investigated this manner.
A study by Okbay et al. (2016) sought to identify all academic achievement genes. From a large multi-ethnic population, they found 74 loci that explained at least 20% of this variable's inter-individual variation.
Conclusions on human behaviour heredity
As you saw, genetic inheritance explains our species' behaviour very well. In many cases, the genome accounts for over half of variability. To return to the example, academic success involves luck.
However, much remains to explore. Genetics remains unknown compared to other human nature domains. Even with environmental factors, numerous aspects must be considered to explain human behaviour.
Currently, these analyses help explain IQ and some illnesses. This understanding will improve therapy, education, and peer cohabitation. Hopeful travellers travel the long road.