I disagree. "We" are different from most people.

I know PLENTY of plain, boring people who have not changed in years. They may come into contact with new stimuli - gobs and gobs (especially when I get done with them in the exam room) but they don't react to it. It makes no change in their personality or behaviors. I believe they just chalk the experience up to something "weird" and go back to their comfortable view of the world.

You are correct that we come into contact with stimuli all our lives, but many people ignore it, especially after age twenty.

"We" may be different, in that we investigate the stimuli as children would. Our personalities may be a little more malleable than most, due to excessive schooling? Too much Pepsi?