Five Myths of Developmental Psychobiology PSC 113 Jeff Schank

Myth 1 Myth 1: Development, including behavioral development, proceeds according to a program or blueprint represented in the genes. – As we will see, the development of organisms is not regulated by a program encoded in an organism's genes, nor is development represented as a blueprint in the genes. – Instead, development is an epigeneic process (i.e. a process of emergent development in which stages emerge from the conditions present at previous stages such as environmental factors, gene regulation, and expression; not to be confused with epigenetics). – Genes do not function as programs or blueprints but rather they function in networks (much like neural networks), which interconnect to other networks at different levels of organization.

Myth 2 Myth 2: Good causal explanations of the development of behavior must proceed up from the genes, nervous system, or hormones. Causation is never from the top down. – This comes from the view that the best scientific explanations ultimately come from the more basic sciences because organisms are composed of the things physicists, chemists, and molecular biologists study – Therefore, causal explanations must go from the bottom up and developmental processes are ultimately explained by the basic sciences on the upward causation only view. – As we will see, however, this ignores organismal composition and how components at different levels of organization interact – When the components of a biological system interact, we have networks of causal interactions – With networks, there can be causal loops that connect different levels of organization (e.g., gene expression to behavior and behavior to gene expression)

Myth 3 Myth 3: Since ontogeny does not recapitulate phylogeny, and evolution and development occur on different time scales, the sciences of evolution and development can proceed relatively independently of each other – In this view, the study of psychological and behavioral development in organisms can proceed independently of the study evolution – But, to survive and reproduce, organisms must not merely be adapted as adults, they must have adaptations specific to the ontogenetic niches they inhabit during development – Likewise, the study of evolution cannot ignore the constraints imposed by development on the evolution of organisms.

Myth 4 Myth 4: The only mechanism for transmitting information developmentally from one generation to the next is gene transmission – This is the view that the trans-generational information necessary for the development of offspring is not solely transmitted from parents via the genes – There are other modes on informational transfer from generation to generation (e.g., epigenetic and cultural transmission)

Myth 5 Myth 5: The causes of behavior can always be partitioned into that component due to nature or nurture (i.e., nature + nurture = behavior) – Nature vs. nurture is a misleading distinction – Nature is typically taken to mean genes and nurture to mean experience – Understood this way, the distinction fails to recognize that genetic and experiential components are parts of interacting networks that span multiple levels of organization – Because of these interactions, we cannot completely partition causes into proportions caused by nature and by nurture

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