In this chapter we outline a history of various strands of behavioural research pertaining to consumer behaviour. We first look at the current field of consumer behaviour research qua a sub-discipline of marketing. This discussion reveals the multidisciplinary nature of the field, which turns us next to the history of general trends in psychology that exert influences on many disciplines, and then to more specific developments in behavioural research at the intersection of economics and psychology. In the last section we review how these strands of behavioural research have been taken up by legal scholars at various points in history. Keywords: history of behavioural sciences, consumer behaviour, multi-and interdisciplinarity, behavioural sciences and law, history of economics, history of psychology Malecka, M. and Nagatsu, M. (2019) 'How behavioural research has informed consumer law: The many faces of behavioural research' in Hans-W. Micklitz, Anne-Lise Sibony, Fabrizio Esposito (eds.) Research handbook on methods in consumer law: A handbook. Edward Elgar Publishing. Earlier Draft: Please cite the published version. Malecka, M. and Nagatsu, M. (2019) 'How behavioural research has informed consumer law: The many faces of behavioural research' in Hans-W. Micklitz, Anne-Lise Sibony, Fabrizio Esposito (eds.) Research handbook on methods in consumer law: A handbook. Edward Elgar Publishing. Earlier Draft: Please cite the published version. claims about (i) the disciplinary identity, (ii) the extension of the target domain of study, and (iii) the multidisciplinary nature of consumer behaviour research. We will discuss them in turn. 2.1 Identity Concerning the identity of consumer behaviour research, Macinnis and Folkes (2010) claim that it is a sub-discipline of marketing. This means that institutionally speaking, much of consumer behaviour research takes place as part of the marketing discipline. One may wonder why this fact is worth establishing. The sub-disciplinarity of marketing, it turns out, refers to an attempt and (perceived) failure for consumer behaviour researchers to establish their own discipline with distinctive normative and theoretical orientations. The commissioned studies on education in business schools in the late 1950s pointed out a need for more theoretical, research-based business education, to which business schools responded by hiring more research-oriented academics. Some of these new breeds focused on consumer behaviour as an object of research, and sought for institutional independence from marketing by founding the Association for Consumer Research (1969), publishing textbooks (e.g. Engel et al. 1968; Kassarjian & Robertson 1968) and launching the flagship Journal of Consumer Research in 1974; their wish to distance themselves from marketing was also motivated by general concerns about potential negative societal impacts of advertizing and marketing of big businesses in the late 1960s. Despite this wish, much of consumer behaviour research nowadays takes place within marketing department...