Executive functions are a set of mental abilities that are mediated by the frontal lobes. These include planning, analyzing, considering alternative actions, abstraction, changing sets, etc. These critical mental functions help people adapt to a complex and ever-changing environment. When the frontal lobe is damaged, people lose executive functions. They become more impulsive, disorganized, unable to plan, and unable to monitor and regulate their own behavior. In effect they become more childlike, regressing to a time when the frontal lobe was less developed.