The University of Pennsylvania Wharton school of Business recently interviewed Marketing Professor and Jay H. Baker Retailing Center Director Barbara Kahn about her research on food consumption habits for the March 20, 2014, edition of its [email protected] series. Describing how product shape and size affect consumer perception, Kahn noted that individuals will eat more of a particular food item if they perceive it as “incomplete,” that is, if the product is broken into pieces or presented with holes in it. A study co-authored by Kahn and published in the America Marketing Association’s Journal of Marketing Research apparently supported these findings, suggesting that consumers “overweight the completeness” of a product in their decision-making process.

“[P]eople are not normative decision-makers,” explained Kahn. “They don’t eat what they think they need to eat to feel full. They eat what they perceive is the right amount, and they use these implicit rules for deciding how much to eat.”

In addition, Kahn has investigated the impact of visual and verbal displays on consumer choice, including the best ways to present a wide variety of products to shoppers. “We do show that you can manipulate what the expectation is, and change people’s behavior,” she concluded, pointing to a study in which consumers were offered rolls and cheeses with holes in them. “When we called it a roll or cheese, people thought the ones with the holes were less compete. They tended to consume more of the holey bread. On the other hand, if we set the expectation that it was a bagel, or that it was swiss cheese, their thought was: ‘A whole bagel has a hole in it.’That reversed the findings.”