Consumer behaviour is the study of when why how and where people do or do not buy a product. It blends elements from psychology, sociology, social anthropology and economics. It attempts to understand the buyer decision making process, both individually and in groups. It studies characteristics of individual consumers such as demograpics and behavioural variables in an attempt to understand peoples wants. It also tries to assess influences on the consumer from groups, and society in general. Customer behaviour study is based on consumer buying behaviour, with the customer playing the three distinct roles of user, payer and buyer.