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
Can we learn anything from ants?
Is complexity simple?
Ants