This chapter refers to an ethnographic study of consumer testing in the perfume industry carried out in 2007, whose detailed results have already been published. The chapter also uses marginally some ethnographic materials gathered in 1999 on the use of methods of experimental economics in the study of consumer behaviour and a few theoretical insights elaborated elsewhere. Notable interest in the vocabulary of performativity has been expressed in recent contributions to the study of marketing and market research practices. This interest is justified by the obvious: whereas sometimes marketing practitioners are struggling to grasp an elusive and indiscernible reality, at other times this reality - of consumer behaviour, market trends and shopping desire - is explicitly conceived as the outcome of their tasks. A number of notable contributions to the social understanding of technological testing have emphasized the problematic distance that exists between what is produced inside the testing venue and what this is meant to refer to outside.