Data for this project came from a larger study funded by the German Federal Ministry of Education and Research (BMBF; reference number 01GWS068). All responsibility concerning the content is with the authors, whereas the funding source did not have any involvement other than the financial support for gathering data. We also thank the German Academic Exchange Service (DAAD) for making this project possible through facilitating international collaborations. Svitlana Iarmolenko was involved in conception and design; analysis and interpretation of data; drafting the article. Peter F. Titzmann was involved in conception and design; collection, analysis and interpretation of data; drafting the article. Rainer K. Silbereisen was involved in securing funding, managing data collection, and critical revisions of the article. The authors confirm that they have access to the original data on which the article reports.