Subliminal Advertising: does it work?

Subliminal advertising is a method of promotion that is meant to influence consumer's responses using images, sounds, and other various techniques without them being conscious of it.

Here's a famous example:

In 1957, a market researcher named James Vicary flashed the words "Eat Popcorn" and "Drink Coca-Cola" onto a drive-in movie theater.

The words appeared for only one single frame, not long enough for the conscious mind to be aware of it, but long enough for the subconscious to take it in. Supposedly this subliminal ad increased sales by 20% for Coke, and 60% for popcorn. 

That is a massive spike.

However, it was a hoax. But more recent experiments have shown that subliminal messages can affect behavior, in a smaller way. 

Image courtesy of businessinsider.com