In general, teens will have teen passengers in their car because they are their peers that they spend time with, go to the same places as, and enjoy the company of. However, it is difficult to prevent the behaviors that the passengers cause because teen drivers tend to yield to peer pressures and overestimate their abilities when peers are around. It is very difficult to alter a teens perspective when they are aiming for social acceptance. Also, teens are less likely to think things through when they are proposed. In fact, there is evidence from MRI research that the prefrontal cortex (the area of the brain responsible for planning, impulse control, and executive decision-making) does not mature fully until the early to mid-20s. Thus, social and biological factors can influence their decisions on the road.