Consumer behaviour is the study of how people buy, what they buy, when they buy and why they buy. It is a subcategory of marketing that blends elements from psychology, sociology, sociopsychology, 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 demographics, psychographics, and behavioural variables in an attempt to understand people's wants. It also tries to assess influences on the consumer from groups such as family, friends, reference groups, and society in general

Models of Consumer Behaviour

One of the best known models explaining the interactions involved is that of Howard and Sheth. This contains a deal of common sense, although, as is often the case with such models, the rather obscure terminology makes it appear more confusing than it really is. The 'inputs' (stimuli) that the consumer receives from his or her environment are:

1. significative - the 'real' (physical) aspects of the product or service (which the co make use of)
2. symbolic - the ideas or images attached by the supplier (for example by advertising)
3. social - the ideas or images attached to the product or service by 'society' (for example, by reference groups)

The 'outputs' are what happens, the consumer's actions, as observable results of the input stimuli.

Between the inputs and outputs are the 'constructs', the processes which the consumer goes through to decide upon his or her actions. Howard and Sheth group these into two areas:

1. perceptual - those concerned with obtaining and handling information about the product or service
2. learning - the processes of learning that lead to the decision itself

The Engel-Kollat-Blackwell model (EKB Model), as a further example, follows a more mechanistic approach.

In the domain of evolutionary economics, consumers are seen as active agents following rules of behaviour, fairly easy to follow and implement because they require only a limited amount of information and capability of elaboration. For instance, a consumer, being aware of a certain need and believing a certain good category satisfies it, might fix a maximum price he/she can afford and search for the best good available under such a constraint.

A more detailed description of rules of behaviour, dependent also on consumer's income and social group, is available at Consumer Decision Rules for Agent-based Models by Valentino Piana (2004). More in general, consumer behaviour models and datasets are available at Consumer theory: the neoclassical model and its opposite alternative.

Such models can help theorists to explain consumer behaviour better, but it can be difficult to put them to practical use.

The behavior of the economy as it effects consumers is reported in the "Lally Consumer Value Index" (LCVI). This quarterly index compiles 20 components that effect the consumer's economy and weights their input to gauge government policymakers' management of the economy for consumers. This index was conceived to give consumers a better understanding of what is helping or hurting their financial and social well being, more accurately and in broader terms than the government's Consumer Price Index (CPI) that only considers one component, prices of products and services. The improved Lally Consumer Value Index (LCVI) was originated by Eugene F. Lally a research economist. The Index also includes Lally's theory of "evolutionary expectations" which correctly interprets the weight of consumer "price" changes in the LCVI as opposed to the government's handling of "price" changes in the Consumer Price Index (CPI).