Part of Kavner's contract says that she will never have to promote "The Simpsons" on video and she rarely performs Marge's voice in public because she believes it "destroys the illusion. People feel these are real people." Kavner takes recording sessions seriously, and feels that voice acting is "a little more limiting than live acting. And I have nothing to do with my character's movement." Nancy Cartwright, who voices Bart Simpson, said in her book "My Life as a 10-Year-Old Boy" that Kavner is "a workhorse of an actor" with "extraordinary professionalism and quiet work ethic", and notes that she is rarely late for recording sessions.