The work of Charles Darwin has had a big impact on the world, particularly in the sciences. While he hypothesized and theorized a lot of things some of his research works were more salient to psychology compared to other aspects. According to Darwin, animals and humans descended from a common ancestor.
Since Darwin stated that animals and human have a lot in common, studying animals to learn human behavior increased in popularity. Although scientists had studied animals for many years and made inferences from these animals, theories of Darwin led to scientists making inferences about behavior of humans, emotions, memory, and social interaction based on experiments and observations with animals.
Darwin’s theories also resulted in increased research in the psychology of individual differences. Prior to his theories, many scientists tried to understand human by examining similarities and averages between people. These researchers were just trying to comprehend the basic underlying concepts of human behavior. After Darwin, psychologists started to study individual differences. Today, many researchers focus on intelligence when investigating individual differences. Some psychologist also focuses on human traits that make some individual more successful than others. This is based on Darwin theory of natural selection where the most adaptive and strongest species survives and the weak dies.