Changes in personality are often attributed to damage in the frontal lobe. This area is crucial for the development of personality, sense of self and humor development. It is also important in the development of affective-emotional responses. Damage to this area can result in disinhibition and inappropriate joking. It can also cause an inability to understand indirect communication, such as sarcasm.
Damage to the right frontal lobe can also cause problems with organizing and integrating information.