What is sensation? Give an example.

Sensation is the immediate response of our sensory receptors (those in our eyes, ears, nose, mouth, and skin) to such basic stimuli as light, colour, and sound.
One "neuromarketing" study, using brain-scanning (fMRI) technology, found that when no brand name was presented prior to tasting cola beverages (i.e., consumers relied only on sensation), the reward centres of the brain lit up and Coke and Pepsi were equally preferred. But, when explicitly told the brand name before drinking, more consumers preferred Coca-Cola, and an entirely different part of the brain lit up-the medial prefrontal cortex. This is the area of the brain responsible for thinking and judging. Learned meanings about the brand influenced consumers' ultimate perceptions of Coca-Cola.
Thus, based on sensation alone, consumers might equally prefer Pepsi and Coke. However, our ultimate preferences are also shaped by our perceptions-the way in which we organize, interpret, and form associations about the brand.