Several theories exist to explain the process of human development. The following will discuss five individual, influential theories of development and how they relate to age-related milestones throughout the lifespan.
Biology and Evolutionary Theories emphasize that the factors that motivate human behaviour are both genetic and biological process, and that they have gradually changed over time through a process of genetic mutation, natural selection, and evolution (Bee, Boyd, & Johnson, 2018). Associated with these theories are the study of genes, patterns of inheritance, behaviour genetics, ethology, evolutionary psychology, as well as the work of influential evolutionist Charles Darwin, who believed that the development of the human species could understood by studying child development (Bee, Boyd, & Johnson, 2018).
Psychoanalytic Theories suggest that adult behaviour and emotions stem from childhood experiences (Bee, Boyd, & Johnson, 2018). Notable psychoanalyst Sigmund Freud developed a Psychosexual Theory which suggests that personality develops in five separate stages from the time of birth through to adolescence, with each stage focusing on an erogenous zone of the body associated with the need for physical pleasure (Schultz, & Schultz, 2013). Erik Erikson proposed a Psychosocial Theory, which suggests development is the result of an interaction between internal drives and cultural demands, and that personality develops across the lifespan through a process of eight