You are sitting with your friends, talking about the latest movie you and your friends just saw. One of your friends mentions that theaters use subliminal messages while showing a movie to influence people to buy refreshments such as popcorn. Another friend says she has heard that some music artists insert subliminal suggestions in their music. Subliminal messages have been somewhat of an urban legend for some time; even the originator of the idea, James Vicary, admitted that his claims were just a hoax.
From scientific and biological perspectives, why wouldn’t subliminal messages work? If they don’t, then why do people still think that they do? How would you explain to your friends (without starting a heated argument) that subliminal messages cannot influence the behavior of an entire group, for example, convince the entire audience in a theater to buy popcorn?