In 1957, an amateur psychologist named James Vicary fl ashed imperceptible messages on a screen during showings of the fi lm Picnic. The messages were “Hungry? Eat popcorn” and “Drink Coca-Cola.”...

In 1957, an amateur psychologist named James Vicary fl ashed imperceptible messages on a screen during showings of the fi lm Picnic. The messages were “Hungry? Eat popcorn” and “Drink Coca-Cola.” Although Vicary claimed these “subliminal ads” increased sales of popcorn and Coke, research proved him wrong. However, the ads did have the effect of arousing hostility toward Pavlovian conditioning. Was Vicary’s amateur experiment really a study of Pavlovian conditioning?