Perception
How a consumer determines what they will buy is heavily influenced by their perception of the situation they are in at that moment in time. Perception is the process by which consumers select, organize, and interpret information and environmental stimuli in order to form a more meaningful picture of the world around them.
One of the most massive forms of environmental stimuli is advertising. On average, consumers are exposed to 3000 - 5000 advertisements everyday. It is physically impossible for a consumer's brain to actively pay attention to all of that stimuli. Add to that all of the other environmental stimuli around them: smells, tastes, sounds, conversations; it's a wonder that humans are able to concentrate on anything at all. As a result, the brain controls what stimuli it will engage with. It is this process that creates perception. Consumers form their perceptions through the brain's distinct processes of selective attention, selective distortion, and seletice retention.
Perception is selective. We see what we want to see. The following perceptual processes shed more light on perception.