Reteratals (2000), define consumer behaviour as “the physical action of consumer that can be directly observed and measured by othersâ€. Consumer behaviour is seen as overt behaviour by Reteratal.  It is called overt behaviour to distinguish it from mental activities such as thinking that cannot be observed directly.

Achumba (1996), view consumer behaviour as “the activities of people engaged in actual or potential use of market items whether products, services, information or ideasâ€.  In other words, consumer behaviour is simply those act of individual, directly involved in obtaining and using economic goods and services presently or as in the future.

American Marketing Association(AMA); (1995), define consumer behaviour as “the dynamic interaction of affect and cognition behaviour and the environment by which human beings conduct the exchange aspect of their livesâ€.  The term affect refers to feelings, responses, or emotional reaction whereas cognition means mental responses such as thinking, remembering or knowing.

Philip and Gray(2004), define consumer behaviour as “the buying behaviour of the final consumer – individual and households who buy goods and services for personal consumptionâ€. Consumption is a concrete, physical and observable behaviour, such as a consumer purchasing a packet of milk.  Consumer behaviour includes mental operations which are not directly observable, such as the decision to engage in low fat dieting and to refrain from eating snacks.  Behaviour may be reasoned and deliberated upon.  It may be impulsive, such as an order at a bar.  It is habitual like buying the same brand always.  It is not only acts but motives and causes are taken into consideration when embarking on consumer research to find out whether display of products persuade consumers to buy or if consumer do care about the opinions of others.

Consumer behaviour plays a major role in marketing of goods and services.  Consumer behaviour is not restricted to only individual behaviour but also group behaviour.  Most consumers exhibit their behaviour on behalf of other but towards product or services the behaviour may likely be different. Consumer behaviour deals with scarce goods and services; and frequently include a cycle consisting of orientation, purchase, use and disposal.

2.2   Importance and Difficulty of Understand Consumer   Behaviour
According to Ugboji (2003) “the success of any marketing programme depends on the ability of the marketer to understand how consumer behaveâ€. Therefore marketer should have quality  data on the number of people living in each of the geographical region, how many are school graduates, what is their income capacity and choice for some brands, Demographical and economic factors alone may explain why consumers always choose to buy a particular brand of product.  However, consumers are influenced by cultural factors which is our area of study or interest.  Demographic and economic factors do not satisfactorily explain some variations in personal behaviour.  These factors alone cannot account for the differences between the person who loves to look and the one who does not, or preferences for soft drinks, in blind-test where consumers cannot differentiate one brand from another.