some results from Scottish data Topic smoking behaviour and friendship Problem influence and/or selection Theory drifting smoke rings (Pearson, West, Michell) Data three wave panel ’95’96’97, school year group, age Method SIENA modelling

some results from Scottish data skip through to Theory Smoke rings (Pearson & Michell 2000) and Drifting smoke rings (Pearson & West 2003) Group position determines smoking behaviour (influence effects) – peripherals most unstable? (P&M) – peer pressure strongest in groups? (O&D) – isolates most stable smokers? (E&B) Smoking behaviour determines group position (selection effects) – peripheral smoking rewarded by acceptance in a smoking group? (P&W) – group smoking punished by rejection in a non-smoking group? (O&D) – isolate smoking breeds further isolation? (P&W)

some results from Scottish data Modelling (A) group position as local cohesion, e.g., reciprocity: group member is embedded in many reciprocal dyads peripheral is attached to others, but not reciprocated isolate is not part of any reciprocal dyad Problem:reduction to one explanatory dimension

Modelling (A) include effects of » reciprocity » similarity » similarity × reciprocity into the objective functions for network and/or behavioural change of actor i. some results from Scottish data

Modelling (A) include effects of » reciprocity » similarity » similarity × reciprocity into the objective functions for network and/or behavioural change of actor i. some results from Scottish data similarity

some results from Scottish data Modelling (B) group position as specific configuration of the neighbourhood group member belongs to clique of three peripheral is unilaterally attached to group isolate has no incoming ties Problem:reduction of ‘explanatory data’, loss of statistical power

some results from Scottish data Modelling (B) include effects of » isolate status » group status » peripheral status » similarity » group status × similarity » peripheral status × similarity into the objective functions for network and/or behavioural change of actor i.

some results from Scottish data Results (A) SIENA “target statistic” descriptives Average statistic observed per actor and time interval. Second column: expectations under independence.

Results (A) SIENA parameter estimates: basis model some results from Scottish data

Results (A) SIENA parameter estimates: basis model some results from Scottish data

Results (A) SIENA parameter estimates: basis model some results from Scottish data

Results (A) SIENA parameter estimates: basis model some results from Scottish data

Results (A) SIENA estimates extended models: similarity × reciprocity in network model (all other parameters barely change) some results from Scottish data

Results (A) SIENA estimates extended models: similarity × reciprocity in behavioural model some results from Scottish data

Results (A) SIENA estimates extended models: same model with prev. estimates as starting value some results from Scottish data

some results from Scottish data Results (B) SIENA “target statistic” descriptives Average statistic observed per actor and time interval.

some results from Scottish data Results (B) SIENA parameter estimates group position in behavioural model

some results from Scottish data Results (B) SIENA parameter estimates same without peripheral status effect

some results from Scottish data Influence question Are peripherals most unstable? Yes… –influence is strongest in asymmetric relationships but… –results do not strictly distinguish between peripherals and isolates. If a peripheral is attached to a homogeneous group, the asymmetric influence effect can be decisive.

some results from Scottish data Influence question Is peer pressure strongest in groups? Definitely not. –reciprocity ‘cools down’ the similarity effect, influence is strongest in asymmetric relationshipss –(effect not shown here:) there is a non- significant preference for group homogeneity after controlling for reciprocated similarity There is peer influence, but not predominantly in groups.

some results from Scottish data Influence question Are isolates most stable smokers? No. –neither isolation nor indegree have a significant impact on behavioural preference. On the contrary… –isolates may be extremely unpredictable (as there is no reciprocation of friendship tempering the influence of their perceived friends).

some results from Scottish data Selection question Is peripheral smoking rewarded by acceptance in a smoking group? Not this easily. –main effect sim×rec on network is negative, so there is a net negative tendency to have additional smokers in a smoking group –question is: does tie creation differ here from tie dissolution?

some results from Scottish data Selection question Is group smoking punished by rejection in a non-smoking group? Not either. –main effect sim×rec on network is negative, so there is a net positive tendency to have smokers in a non-smoking group. –question is again: does tie creation differ here from tie dissolution?

some results from Scottish data Selection question Does isolate smoking breed further isolation? ‘Indirect evidence’ supports claim… –smokers are significantly less chosen as friends, –(effect not shown here:) unpopular others are significantly less chosen as friends; isolates are “extreme unpopulars”

some results from Scottish data Literature E&BS. Ennett & K. Bauman (1993). Peer Group Structure and Adolescent Cigarette Smoking: A Social Network Analysis. Journal of Health and Social Behavior 34(3): O&DE. Oetting and J. Donnermeyer (1998). Primary Socialization Theory: the Etiology of Drug Use and Deviance. Substance Use and Misuse 33(4): P&M M. Pearson & L. Michell (2000). Smoke Rings: Social Network Analysis of Friendship Groups, Smoking, and Drug-Taking. Drugs: Education, Prevention and Policy 7(1): P&WM. Pearson & P. West (2003). Drifting Smoke Rings: Social Network Analysis and Markov Processes in a Longitudinal Study of Friendship Groups and Risk-Taking. Connections 25(2):59-76.