away from it". Another factor that influences the evaluation process is the degree of involvement. For example, if the customer involvement is high, then he/she will evaluate a number of brands; whereas if it is low, only one brand will be evaluated. Purchase decision This is the fourth stage, where the purchase takes place. According to Kotler, Keller, Koshy, and Jha (2009), the final purchase decision can be disrupted by two factors: negative feedback from other customers and the level of motivation to comply or accept the feedback. For example, after going through the above three stages, a customer chooses to buy a Nikon D80 DSLR camera. However, because his good friend, who is also a photographer, gives him negative feedback, he will then be bound to change his preference. Secondly, the decision may be disrupted due to unanticipated situations such as a sudden job loss or the closing of a retail store. Post-purchase behavior These stages are important to keeping customers. Customers match products with their experiences on whether they are either content or discontent with the product. This affects the decision process for resemblant purchases from the same company in the future, mainly at the information search stage and evaluation of alternatives stage. If brand loyalty is made then customers will often fast-tracked or skip completely the information search and evaluation of alternative stages. Either being content or discontent, a customer will spread good or bad opinions about the product. At this stage, companies try to make favorable post-purchase communication to encourage the customers to purchase. Also, cognitive dissonance (consumer confusion in marketing terms) is common at this stage; customers often go through the feelings of post-purchase psychological tension or anxiety. Questions include: "Have I made the right decision?", "Is it a good choice?", etc. Models of buyer decision-making There are generally three ways of analyzing consumer buying decisions: Economic models - largely quantitative and are based on the assumptions of rationality and near perfect knowledge. The consumer is seen to maximize its utility. See consumer theory. Game theory can also be used in some circumstances. Psychological models - psychological and cognitive processes such as motivation and need recognition. They are qualitative rather than quantitative and build on sociological factors like cultural influences and family influences. Consumer behavior models - practical models used by marketers. They typically blend both economic and psychological models. In an early study of