Human Development and Dynamic Systems Theory

My ambition is to restructure dichotomous conversations—inside the academy, in public discourse, and ultimately in the framing of social policy—in order to enable an understanding of the inseparability of nature/nurture. My current case studies in this area examine the emergence of gender differences in behavior in early childhood. Newspapers are awash with reports of genes for this or that complex human trait (obesity, alcoholism, homosexuality, gender differences in math and science). A divide exists between people who accept biological explanations of human difference and those who reject biology in favor of social explanations. But the very premise of nature versus nurture is misguided. Dynamic systems theory permits us to understand how cultural difference becomes bodily difference.

Dynamic systems theory permits us to understand how cultural difference becomes bodily difference.Systems thinkers consider the dynamic interactions of all the factors contributing to a particular trait of interest; these may balance one another to attain stability, or, when for some reason one or more factors change, the dynamic balancing act can destabilize a system and lead to change. Change occurs when a system first becomes destabilized but after a time reaches some new stable state. There is significant and exciting literature on systems biology (at the level of cells and molecules), developmental psychology (especially the development in infants of motor skills such as walking and directed reaching), and at the level of individual neurons as they connect to form neural networks.A key concept is that, rather than arriving preformed, the body acquires nervous, muscular and emotional responses as a result of a give and take with its physical, emotional and cultural experiences.

To date only a few have suggested that these ideas might be productively applied to the study of the emergence of gender differences, gender identity, human sexuality, or racial and gender-based disparities in health outcomes. So far, my method has been to apply systems approaches to specific examples at different levels of human organization (organ physiology, sex differences in behavior, human sexuality and gender identity) as “proofs of concept”—which I call case studies—for a systems approach.


Phenotype (The expression of traits)

The question that interests me is, how does development produce a phenotype?
With dynamic systems, we’re almost always talking about sex differences, rather than sex dimorphism (for example, the development of genitalia).Sex differences are small average differences that begin to appear in infants, children, and then adults. There are four major goals of dynamic systems:

  • First, to understand the origin of novelty in development.
  • Second, to reconcile global regularities with local variability, complexity, and context specificity.
  • Third is to integrate developmental data at many levels of explanation. For example, systems theorists want to understand how the development of speech interacts with the development of the motor system. To provide a biologically plausible yet non-preformationist account of behavioral development we need to understand how local processes—the individual things that are going on day-to-day and moment-to-moment in infant and child development—lead to global outcomes.
  • Lastly, to establish a theoretical basis for generating and interpreting empirical research on sex differences specifically.



a. Anne Fausto-Sterling, Cynthia Garcia Coll , Meaghan Lamarre “Sexing the baby: Part 2 applying dynamic systems theory to the emergences of sex-related differences in infants and toddlers” Social Science & Medicine 74 (2012) 1693-1702 (contact author for a copy).

b. Keller, E. F. (2010). The Mirage of a Space Between Nature and Nurture. Durham: Duke University Press.

c. Diamond, L. M. (2007). A dynamical Systems Approach to the Develoment and Expression of Female Same-Sex Sexuality. Perspectives in Psychological Science, 2(2), 142-161.

d. Hollenstein, T. (2007). State Space Grids: Analyzing dynamics across development. International Journal of Behavioral Development, 31, 384-396.

e. Thelen, E. (2000). Grounded in the World: Developmental Origins of the Embodied Mind. Infancy, 1(1), 3-28.

f. Rovee-Collier, Carole. (1999) The Development of Infant Memory. Current Directions in Psychological Science 8:3. Pp80-85.

g. Gottlieb, G. (1997). Synthesizing Nature-Nurture: Prenatal Roots of Instinctive Behavior. Mahwah: Lawrence Erlbaum.

h. Thelen, E. (1995). Motor Development: A new Synthesis. American Psychologist, 50(2), 79-95.

i. Thelen, E., & Smith, L. B. (1994). A Dynamic Systems Approach to the Development of Cognition and Action. Cambridge: MIT Press.