1. "Perception is the process by which organisms interpret and organize sensation to produce a meaningful experience of the world. Sensation usually refers to the immediate, relatively unprocessed result of stimulation of sensory receptors in the eyes, ears, nose, tongue or skin. Perception, on the other hand, better describes one's ultimate experience of the world and typically involves further processing of sensory input. In practice, sensation and perception are virtually impossible to separate, because they are part of one continuous process."
Peter Lindsay & Donald A. Norman: Human Information Processing: An Introduction to Psychology, 1977.
2. "Process by which people translate sensory impressions into a coherent and unified view of the world around them. Though necessarily based on incomplete and unverified (or unreliable) information, perception is 'the reality' and guides human behaviour in general."
Perception is a way which people see things. Each of us receive stimuli by seeing, hearing, smelling, tasting, touching but we interpret it differently. I mean that not everybody has to see something the same, smell etc.
Now I will put some pictures which can prove that not every person will notice first the same thing on picture:)
Depends how you look on the picture you can notice there two faces looking at each other or vase.
What did you see first? :)
Have you seen first horses? :)
Do you see a couple or skull?
Monks or waterfall??
Now try to count black points ... it is not so easy ... even impossible ;)))
I think that for example commercials has big influence at people stimuli. I will try find an example which shows it :)
Usually when in commercials we see babies it takes more our attention and it's also quite funny. This one present baby's nappies. Music is very optimistic "Don't worry, be happy" which is well-known for everybody.