I think there's a preponderance of scientific evidence to show that there's probably some kind of effect on you as a member of homo sapiens, even if it's not necessarily conscious or not exactly as strong as advertisers claim it is to their clients.
For example, would you say you are immune to the Mere-exposure Effect [0]? Absent some particular gripe, you'll unconsciously give an edge in preferences to a brand you've heard about versus one you haven't.
