> how come there are so many more 40 year olds in prison than 20 year olds? You'd want to look at the age at which someone committed the crime for which they a

> how come there are so many more 40 year olds in prison than 20 year olds? You'd want to look at the age at which someone committed the crime for which they are imprisoned, not their current age, to assess the affect of age on crime-related statistics. Also, the juvenile justice system typically lets people out at 18 or 20, unless they were charged as an adult. So you don't have the same buildup of late teenagers being imprisoned at 20 as you do for people who are older. It is factually the case that brain development continues until around age 25. The impulsive areas of the brain develop/myelinate earlier than than the prefrontal cortex, for example, which exercises executive function and impulse control.