Is success genetic? | Kathryn Paige Harden

The relationship between heritability and response to the environment is complicated. Heritability is the proportion of variation in a population due to genetic differences between people.

People often misinterpret heritable as 'genetically determined and unmodifiable by the environment.' But it doesn't mean that. Genetic studies that ignore the environment and only look for the main effects of genes require sample sizes above one million people. Adding gene-by-environment interaction, the problems get even bigger.

Just because a gene influences the probaility of an outcome in one group of people to the point that it's probabilistic rather than deterministic doesn't mean that it is portable when another group of people are studied.

Heritable means that within a group of people that have experienced roughly equivalent environmental conditions,  genetic differences between them are related to the phenotypic differences between them.

Imagine a garden with the perfect amount of sunlight and different flowers in the garden. The difference between the plant's heights is because of the different seeds planted. The differences are genetic.

Imagine another garden with different flowers that are neglected. The flowers will be shorter than the plants in the rich, well-resourced garden. The difference between the tall and short plants across very different environments is not just due to genetics. While this is obvious when it comes to plants, it's difficult for people to keep in mind.