How to get people to see their doctor on time, how to convince people to sort waste, or obey traffic rules? Answers to these questions are given by behavioural science, used increasingly to promote social change. One of the leading centres for behavioural science research is based at University College London. The Centre for Behaviour Change was founded by the world-renowned health psychologist Susan Michie. Under her leadership over the past 10 years, critical research is conducted and the findings put into practice. . Based on more than 80 theories and numerous studies, her team of researchers has defined what determines human behaviour, completely disproving the myth that all a person has to do to change his or her behaviour is to be informed and willing to do so. In reality, there are a total of 26 factors determining a person’s behaviour, including knowledge, skills, social norms, opinion of the desired behaviour, self-efficacy, self-image, values, goals, etc. These factors are divided into three broad groups: capability, opportunity, and motivation. If just one of these components is missing, we cannot expect a person to change his or her behaviour. The COM – B model (capability, opportunity, and motivation) for behavioural change, developed by Michie and her team, helps identify what needs to be done for a behaviour change intervention to be effective. Vita Savicka’s discussion with the Centre for Behaviour Change Professor Robert West on behavioural science and behavioural change communication.