Have you ever crunched through a full bag of potato chips in a matter of minutes and instantly regretted doing so? Do you ever wonder why you feel compelled to finish that last bite of apple pie, even though you’re already full? Cornell University marketing professor Brian Wansink is attempting to answer questions like these as he studies the psychological factors that cause people to eat more than they want to.

Wansink believes there are many factors that determine appetite, and that many of these factors are perceived and acted upon without conscious thought.

Frederick Gibbons, professor of psychology, agrees with this assessment.

“There are many factors that contribute to [over] eating, and hunger is only one of them. Many of them are social, emotional or trivial,” Gibbons said. “Much eating behavior is externally driven and so varying those external cues can influence behavior.”

Wansink has already observed some of the effects such cues have on eating behaviors.

Wansink observed the tendencies for people to eat more M&M’s when there are more colors to choose from and to drink more juice from a short, wide glass than a tall, thin glass.

Wansink has also found evidence that the larger the size of food package, the more frequently these foods will be eaten.

Richard O’Neill, lecturer of marketing, said food companies are well-aware that people are affected by such subtle factors.

“Marketers know what makes people tick, and they use this to their advantage,” O’Neill said. “Look at package labels. They shout ‘no cholesterol,’ ‘no fat,’ all the things that consumers want to hear.”

O’Neill said this form of marketing may not be a bad thing, but it is still up to the consumer to stay healthy.

“It makes us smarter consumers and helps us to realize what marketers are doing. Without this knowledge, marketers have the upper hand,” O’Neil said. “The consumer still has the ultimate say, by just saying ‘no.’ We can’t forget that.”