Original Source:

"Consumer behavior represents the study of individuals and the activities that take place to satisfy their realized needs. That satisfaction comes from the processes used in selecting, securing, and using products or services when the benefits received from those processes meet or exceed consumers' expectations. In other words, when an individual realizes that he has a need, psychological process starts the consumer decision process. Through this process, the individual sets out to find ways to fulfill the need he has identified. That process includes the individual’s thoughts, feelings, and behavior."

Laura Lake, Consumer Behavior For Dommies, 2009, John Wiley & Sons publishing (don't know the page...because it is on-line preview source, I will check it later.)

Paraphrased

In this book, Consumer Behavior For Dommies, Laura Lake defines and explains of the consumer behavior which published by John Wiley & Sons. She mentions that the consumer behavior is a kind of research to investigate people do some actions to achieve their requirement.  She also illustrates that when a person understands that he/she has the requirement to acquire something, this person must have the decisive choice procedure. She ponts out this kind of procedure starts from the mind, thinking and action; people will accomplish it via choosing, buying or receiving service. With this ways and behaviors, people will be contented with their anticipations.