ABSTRACT

One simple way to describe development is ”qualitative transformations during an individual life span.” Development is fundamentally about becoming different from a previous condition, and the job of a developmental scientist is to figure out how this happens. Differentiation is the term used by developmental biologists to label this fundamental developmental process at the cellular level. Differences between males and females, which have come to occupy a lot of thought, provide good examples of predictable divergences in development. Development is constrained by the raw materials available at each stage, is rarely linear, and is often nudged in one direction or another by historical contingencies. The use of ”explanatory”categories such as ”innate” and ”genically fixed” obscures the necessity of investigating developmental processes in order to gain insight into the actual mechanisms of behavior and their interrelations. The process view of development moves forward, starting from material precursors and actions from which organisms can build new states, mechanisms, or actions.