My main research interests focus on understanding environmental behaviour, in particular household energy use and car use. I am especially interested in understanding which individual and situational factors affect intrinsic motivation to act pro-environmentally. Also, I study which factors affect the effectiveness and acceptability of environmental policy and technology. I am involved in various interdisciplinary research projects that aim to understand how to realise a sustainable energy transition. Among other activities, I am past-president of the Environmental Division of the International Association of Applied Psychology, member of the Advisory Group on Energy for Horizon 2020, member of the Board of Directors of the University of Twente, member of the scientific board of the Groningen Energy and Sustainability Program, and associated member of the Dutch Council for the Environment and Infrastructure. Also, I coordinate the European PERSON platform (see www.person.eu) that aims to unite and advise socio-economic research on the human dimensions of sustainable energy transtiions aimed to promote a secure, clean and efficient energy system.