Hanna Liberska is professor at the Institute of Psychology of Kazimierz Wielki University in Bydgoszcz (Poland). She is vice-director of the Institute of Psychology, chair of the Department of Social Psychology and Study on Adolescents as well as a member of the International Society for Research on Aggression and a co-founder of the Research Group on Family and Adolescents in Middle Europe (RGFAME). Her main fields of study are developmental psychology, social psychology, educational psychology and psychology of family.Marzanna Farnicka is assistant professor at the University of Zielona Góra (Poland), Faculty of Education, Sociology and Health Science. She is a member of the Polish Psychology Association, the International Society for Research on Aggression and a co-founder of the Research Group on Family and Adolescents in Middle Europe (RGFAME). Her research interests include family, coping with stress and aggression, and the support of children at school.