According to Williams Belle, the philosophies and theories behind parkour are an integral aspect of the art, one that many non-practitioners have never been exposed to. Belle says he trains people because he wants it "to be alive" and "for people to use it". Châu Belle explains it is a "type of freedom" or "kind of expression"; that parkour is "only a state of mind" rather than a set of actions, and that it is about overcoming and adapting to mental and emotional obstacles as well as physical barriers. Traceur Dylan Baker says, "Parkour also influences one's thought processes by enhancing self-confidence and critical thinking skills that allow one to overcome everyday physical and mental obstacles". A study by "Neuropsychiatrie de l'Enfance et de l'Adolescence" (Neuropsychiatry of Childhood and Adolescence) in France found traceurs seek more excitement and leadership situations than gymnasts do.