Adolescents’ tendencies to seek novel experiences, even at the risk of physical or social harm, might be expected if their capacity to assess risk or compute outcome probability is underdeveloped. Cognitive abilities do continue to develop at this time (Luna et al., 2004; Spear, 2000). According to Piaget, the formal operation period, which is associated with more abstract reasoning, reaches full maturity during adolescence (Schuster and Ashburn, 1992), and may be less well developed in some individuals. Also, the persistence of egocentrism, in which teenagers experience an ‘imaginary audience’ along with the ‘personal fable’ of unique feelings, may cause them to believe they are exceptional and give them a sense of invulnerability (Arnett, 1992; Elkind, 1967). However, only modest cognitive improvements appear from mid-adolescence onward (Luna et al., 2004; Spear, 2000), and even young children exhibit an accurate implicit understanding of probability (Acredolo et al., 1989). Furthermore, there is little evidence that adolescents actually perceive themselves as invulnerable or underestimate risk; in fact, they often overestimate risk, such as the chance they will become pregnant within a year, go to
