According to self-categorisation theory, referent informational influence i
s a process whereby individuals conform to the norms of social groups with
which they identify. This paper investigates whether smoking is a stereotyp
ical attribute of particular social groups and how the group normative infl
uence with regard to smoking may affect group members' personal smoking inv
olvement. A sample of young adults (initial N = 3300) was surveyed at 3 six
-month intervals after leaving their final year of school. Results showed t
hat particular labels (such as rebels, using illegal drugs and riding motor
bikes) were associated with extensive smoking within peer groups. An indiv
idual's smoking status was found to be strongly related to a favourable smo
king norm in the peer group. This relationship was round to be stronger amo
ngst those who strongly identified with their peer group compared with thos
e who were weakly identified. Individuals whose behaviour was discordant wi
th the group norm tended to express weak identification with the group and,
over time, to alter their main friendship group to one with norms that are
more compatible with their own behaviour.