Final answer:
James Vicary's claim about increasing sales with subliminal messages is false.
Step-by-step explanation:
James Vicary's claim that he increased the sale of popcorn and Coca-Cola with subliminal messages is false. In 1957, James Vicary publicly stated that he conducted an experiment in which he flashed subliminal messages saying 'Eat popcorn' and 'Drink Coke' during a movie, supposedly leading to increased sales. However, it was later revealed that Vicary made up the experiment as a publicity stunt, and there is no scientific evidence to support the effectiveness of subliminal messages in influencing behavior.