She is a charismatic 8-year-old girl who made her debut on December 17, 1989, from Season 1 through Season 3, Episode 1 (September 19, 1991) when she turns 8 years old for the duration of the series. From Season 3 onwards she is an 8-year-old girl who exceeds the standard achievement of the intelligence level of children her age. Not to everyone's surprise, she is also the moral center of her family. In her upbringing, Lisa lacks parental involvement of Homer and Marge, which leads to hobbies such as playing saxophone and guitar, riding and caring for horses, and interest in advanced studies. In school, Lisa's popularity is affected by those who view her as a geeky overachiever, which leaves her with only a few friends. She focuses on her goals and strives to reach her potential, and at the age of eight, she is already a member of Mensa with an IQ of 159. Her lack of parental involvement also leads to her lashing out at those who she deems lower than her or even above her. She has extreme jealousy from time to time and will do whatever it takes to reclaim her title as the smartest; but only if she deems it necessary. Otherwise, she's the intelligent and rational one who usually thinks things through.
