Barbara Class is a postdoc researcher interested in among-individual and genetic variation in behaviour, how this variation changes during the lifetime of individuals, and its consequences in terms of survival, reproductive success, and mate choice. To carry out this research, she has been using long term data collected in wild vertebrate populations (birds, lizards) and a variety of mixed (quantitative genetic) models. She is currently investigating whether urban and non-urban great tit populations differ in their quantitative genetic variation for an array of traits and therefore in their potential to respond to selection.