Control the urge to splurge - try dividing things up

April 15, 2008 -- Good things come in small packages — like the Nabisco 100 Calorie Pack. But do these portion-controlled offerings help dieters lose weight?

Yes, according to research by Amar Cheema, assistant professor of marketing at Olin Business School, and his colleague Dilip Soman, professor of marketing at the University of Toronto's Rotman School of Management.

Dividing food into smaller portions creates a "partitioning effect;" a phenomenon where segmenting a resource, such as food or money, can dramatically affect consumption.

"Partitions introduce a small transaction cost. In the case of 100 Calorie Packs, the cost is the action necessary to open a second package," Cheema said. "This transaction cost gives consumers the opportunity to pay attention to how much they're eating and may help many control overeating."

Partitions can reduce the rate of consumption as well as the total amount consumed.

In one study, each participant was given a box of 24 cookies and asked to record how long it took to consume them. Half of the participants' cookies were individually wrapped. The group that received the cookies in aggregate consumed them in an average of six days — compared with an average of 24 days for the group with the individually wrapped cookies.

"Consumption is a meta-decision, one in which we decide whether or not to start eating, but don't consider each individual action," Cheema explained. "Take potato chips, for example. Once we begin eating them, we don't ask ourselves, 'Should I have another?' before each chip."

The introduction of a partition stops automatic behavior and forces the consumer to decide whether or not to continue eating. "If we're trying to curtail a discretionary consumption activity, simply thinking about it might be enough to get us to stop.

"Interestingly, we found similar results when we partitioned money," he added.

Students were given $100 in pretend cash to participate in a gambling study. Some students received one sealed envelope with all the money, and others got 10 sealed envelopes that each contained $10. Individuals with multiple envelopes tended to spend less, sometimes half of what the people with the single envelope spent. "The power of partitioning can reduce spending by 50 percent," Cheema said.

Amar Cheema

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According to Cheema, "The effectiveness of mechanisms like snack packs can diminish over time. People grow accustomed to them and may start eating more than one pack in a sitting. Consumers may require a variety of frequently changing partitions to curb overindulgence."

He also warned of another risk: "Sometimes, calorie-counted packs are touted as being 'guilt-free.' Consequently, people may not keep track of how many they eat in a week and consume more than they would from products in regular packaging. In our research, we find that partitions work well when they are novel and when people are trying to control consumption."

Cheema and Soman's paper, "The Effect of Partitions on Controlling Consumption," will be published in a forthcoming issue of the Journal of Marketing Research.

Editor's note: Professor Cheema is available for live or taped interviews using Washington University's free VYVX or ISDN lines. Please contact Shula Neuman at (314) 935-5202 for assistance.