Relevance of the social perception in perception?

The short answer is, those who control popular media. The public perception is prescribed. In asking this question you are on the first steps to enlightenment. Maybe typing zeitgeist into google will...

Perception means adding meaning to the sensation by the help of past experience. And it is a cognitive process.

Perception is the key analyzing process of information by your brain. It also can be described as your personal view of life and how you view things.

We have perceptions of something, not on it. But note: perception is not a synonym for opinion or belief. It means "the manner in which a thing is viewed or felt."

I understand the concept of Perceptual constancies, but what are the categories/or the classified groups??