Evolutionary psychology is an approach in which evolutionary principles are applied to studying human psychology and behaviour. Key concepts of importance to evolutionary psychology include:

Natural selection. Natural selection is a fundamental idea in biology, which states that individuals with traits which are most advantageous within a specific environment, will be more likely to survive and reproduce within that environment. Genetic variation is the basis of trait variation, and traits are passed on to offspring.

Evolution has shaped the brain. This general idea assumes that natural selection is responsible for all aspects of the body, the brain, psychological mechanisms and our behaviour, either as adaptations or as byproducts of adaptations.

Modularity of mind, massive modularity and domain specificity. These three terms are all variants of a basic idea, namely that the human mind can be divided into functional units which have evolved as solutions to evolutionary pressures at points during our ancestral past. The idea assumes that such functional units have some form of genetic basis.

The universality of phenomena. Some evolutionary psychologists have looked at very large populations, in order to determine the extent to which certain behaviours or attitudes can be seen across different cultures, religious groups and ethnic groups.