15 to roughly 25 is the period when the frontal cortex is maturing, and also the period where peer influence has the most impact on development. The frontal cor

15 to roughly 25 is the period when the frontal cortex is maturing, and also the period where peer influence has the most impact on development. The frontal cortex is highly involved in silencing the fear response, and in determining the socially correct response to threats, particularly threats towards a person's social position (a common theme for studies around violence). 1) I have not read any study however that looked at periods of social uncertainty, but it sounds plausible. 2) My guess would go towards the relation of frontal cortex maturation. Before fully maturation, other parts of the brain "step in" and handle some of the frontal cortex' role, but by around age 25 they stop doing that.