Pregnancy and Birth

The Leiden Consortium on Individual Development (L-CID) study was founded by Marinus van IJzendoorn, Eveline Crone, Marian Bakermans-Kranenburg and Rutger Engels in 2013. It was developed as one of four work packages of the overarching Consortium on Individual Development (CID). The L-CID study is a large-scale longitudinal intervention study in which 500 families with same-sex twins are followed over a six year period. L-CID has a cohort-sequential design with two cohorts: an early childhood cohort (ECC), aged 3-4 at wave 1, and a middle childhood cohort (MCC), aged 7-8 at wave 1. Annual assessments consist of alternating lab- or home visits during which behavioral and neurobiological data are collected. The collected data allow, among others, for testing which child characteristics shape the effect of (manipulated) environmental factors. The aim of L-CID is twofold: 1. To investigate the development of social competence and behavioral control in children between 3 and 14 years old; 2. To dissect the reason why not all children are equally responsive to variations in the social environment.