“Del Giudice seems to imply that a similar epigenetic mechanism “looks around” at the world during the first few years of life to try to figure out if you’re living in the sort of unpredictable dangerous environment that needs a fast strategy, or the sort of safe, masterable environment that needs a slow strategy. Depending on your genetic predisposition and the observable features of the environment, this mechanism “makes a decision” to “lock” you into a faster or slower strategy, setting your personality traits more toward one side or the other.”