Center for Developmental

ResearchÖrebro University, Sweden

Maarten van Zalk, Lauree Tilton-Weaver, Margaret Kerr, Håkan Stattin, Nejra van Zalk

Overview Our main interests Current SIENA studies Main issues & many wishes

Personal interests

Interests Online vs. offline networks (Maarten) Personality: psychopathic traits, Big Five

(Maarten, Margaret) Externalizing: delinquency, bullying,

aggression (Margaret, Håkan, Lauree) Internalizing: depression, social anxiety

(Maarten, Nejra) Parents, peers, & externalizing (Lauree)

Data Seven Schools: up to 8 friends in the school (N =

2,500) Political Socialization Program: Up to 10

friends in school (N = 4,500) 10-to-18: large community, up to 23 friends,

romantic partners, and siblings in the community (N = 4,500)

ONLINE vs.OFFLINE: small community & 89% of all friends found exclusively online (N = 700)

ALL data also have independent parental reports

Recent publications Kerr, M, Van Zalk, M., Stattin, H. (in press). Psychopathic traits moderate

peer influence on delinquency. Journal of Child Psychology and Psychiatry.

Van Zalk, N., Van Zalk, M., Kerr, M. & Stattin, H. (in press). Socialization of social anxiety in adolescent crowds: Punks, goths, and other eye-catching peer crowds revisited. Journal of Abnormal Child Psychology.

Van Zalk, N., Van Zalk, M., Kerr, M. & Stattin, H. (2011). Social anxiety as basis for friendship selection and socialization in a youth social network. Journal of Personality, 29, 499-525.

Van Zalk, M., Kerr, M.. Branje, S., Stattin, Håkan, & Meeus, W. (2010). Peer contagion and adolescent depression: The role of failure anticipation. Journal of Clinical Child and Adolescent Psychology, 39, 837-848.

Van Zalk M., Branje, S. Kerr, M.,Stattin, H., & Meeus, M. (2010). It takes three: Selection, influence, and de-selection processes of depression in adolescent peer networks. Developmental Psychology, 46, 927-938.

Issues & Wishes Moderation / Interaction effects Mediation / Indirect effects

Plotting Simple Slopes

Y' = b1(x1-x1^) + b2(x2-x2^) + b3((x1-x1^)(x2-x2^))

b1 = IV (parenting-ego estimate)b2 = Moderator (delinquency-alter estimate)b3 = Interaction: parenting-ego×delinquency-alter estimate

For x1^ the average parenting score was used

For x2^ the average delinquency score was used

Moderation Approach to graphing: Plot simple slopes

Is there a user-friendly way to visualize and test differences between groups?

Is this the best for two variables with a wide range of values?

Average scores or average for ego/alter? If only for ego or alters, how do you get this information?

Are ego-alter tables the way to go?

Wish: Function in RSiena that can help visualize interaction effects, visualize the slopes for the different effects

Mediation Processes / mechanisms underlying peer

influence effects Crucial for understanding how peer influence

works Stages in influence Indirect effects

Mediation Do negative cognitions mediate peer

influence on depressive symptoms?

Traditional conditions for mediation:

1) X on Y

2) X on Z

3) When X and Z together on Y, only X remains

Mediation Do negative cognitions mediate peer

influence on depressive symptoms?

Recently: Indirect effects of X on Y VIA Z

Friends depr

Targets’ depression

Negative cognitions

MediationDepressive symptoms Cognitions

Behavioral evolution (influence)

Parameter

s.e. Parameter

s.e.

Rate period 1 10.1221***

1.79 8.1231*** 1.43

Rate period 2 10.2134***

1.89 8.975*** 1.31

Linear shape 1.21*** .24 1.45*** .23Quadratic shape 1.12*** .23 1.81*** .33Ego’s negative cognitions

.43*** .08

Average alter .12*** .04 .74*** .12

Average alt

Targets’ depression

Negative cognitions

.74*** .43***

.12***

Mediation Indirect effects of X on Y VIA Z Can we use a Sobel’s test?

Boots-trapping?

Average alt

Targets’ depression

Negative cognitions

.74*** .43***

.12***

Overview Our main interests Current SIENA studies Main issues & many wishes