Epigenetic Theory

Epigenetic theory is an emergent theory of development that includes both the genetic origins of behavior and the direct influence that environmental forces have, over time, on the expression of those genes. The theory focuses on the dynamic interaction between these two influences during development.

Interactivist ideas of development have been discussed in various forms and under various names throughout the 19th and 20th centuries. An early version was proposed, among the founding statements in embryology, by Karl Ernst von Baer and popularized by Ernst Haeckel. A different approach, James Mark Baldwin's "Baldwin effect," is prominent in contemporary discourses. A radical epigenetic view (physiological epigenesis) was developed by Paul Wintrebert. Another variation, probabilistic epigenesis, was presented by Gilbert Gottlieb in 2003. Probabilistic epigenesis is the view that there are bidirectional influences, based on four levels of analysis, on the development of an organism. These levels of analysis are environmental (social, physical, and cultural), behavior, neural activity, and genetic activity. This view encompasses all of the possible developing factors on an organism and how they not only influence the organism and each other but how the organism also influences its own development.

Noted developmental psychologist Erik Erikson developed an idea he called the epigenetic principle that says we develop through an unfolding of our personality in predetermined stages, and that our environment and surrounding culture influence how we progress through these stages. This biological unfolding in relation to our socio-cultural settings is done in stages of psychosocial development, where "progress through each stage is in part determined by our success, or lack of success, in all the previous stages."

The epigenetic theory views development as the result of an ongoing, bi-directional interchange between heredity and the environment. Environmental influences range from the things we lump together under nurture, such as parenting, family dynamics, schooling, and neighborhood quality, to biological encounters such as viruses and happenings in cells. In addition, Hofstede's cultural dimensions theory says that different cultures contribute to environmental influences in different ways. Since epigenetic theory relies on the environment (which varies among cultures) and heredity as influencing development, where and how individuals grow up can forecast their potential development. Socioeconomic status can aid environmental influences for example, access to healthy foods, medicines, and care facilitates positive development.

Genes produce proteins throughout the course of ones life, these proteins can differ in different environments. While the epigenetic view supports the theory that genes are collaborative, not determining an individual’s traits in an independent manner, but rather determine traits in association with the environment, there is no consensus on what percentage of nature or nurture makes us who we are.