Scientific interest in emotions has been growing since the 1980s. Neurologists, psychiatrists and psychologists have sometimes defined emotions as neurophysiological and psychological phenomena that are internal to individuals. This ontology is linked to a desire to show that these phenomena are material (for example, using medical imaging), as if the methods should define the subject. If, on the other hand, we consider emotions to be complex processes that are shaped and managed within a framework of contextualized social interactions, then methods that are more qualitative and open (field observations and in-depth interviews) are an essential component if we are going to understand their signification, the issues involved and how they are regulated. I rely on my research with diplomats and police officers to illustrate how relevant this is if we are to operationalize a notion that makes sense in both the life sciences and the social sciences, that of affective colouring.