Pay attention! Many consumers believe 36 months is longer than 3 years

Feb 14, 2011

Consumers often have a distorted view when they compare information that involves numbers, according to a new study in the Journal of Consumer Research.

"As a consumer, would your preference for a dishwasher depend on whether its warranty level is expressed in months rather than years?" write authors Mario Pandelaere (Ghent University, Belgium), Barbara Briers (Tilburg University, the Netherlands), and Christophe Lembregts (Ghent University, Belgium).

To most consumers, the answer is "yes." The difference between an 84-month and a 108-month warranty looks bigger than the difference between a seven-year and a nine-year warranty, despite the fact that both differences are exactly the same.

"Qualitative information can usually be specified in alternative units," the authors write. "In many cases, however, the specific unit in which information is described is arbitrary. For instance, product quality ratings may be expressed on a scale from 0 to 10 or on a scale from 0 to 100," the authors write. "People typically fail to realize that the unit of quantitative information is arbitrary. They just focus on the number of scale units used to express a certain difference."

As a result, higher numbers seem to represent bigger quantities. This "unit effect" is the reason why consumers perceive a bigger difference between ratings 90 and 95 out of 100 than they do between a 9 or 9.5 out of 10.

In an additional study, the authors found that the unit effect can be used to encourage healthy food choices. In one experiment, participants exiting the lab were offered the choice between a complimentary apple or a Twix® bar. The energy content of these two choices was either expressed in Kilojoules (247 for the apple versus 1029 for the Twix®) or Kilocalories (59 for the apple versus 246 for the Twix®). "Participants more often chose the apple when the energy content was expressed in Kilojoules than in Kilocalories as the former difference (782 Kilojoules) looks much bigger in the latter one (187 Kilocalories).

However, the authors found that the effect was not replicated when people pay close attention to specific attribute information or when people are reminded of the arbitrary nature of the unit in which information is expressed.

Explore further: Digital native fallacy: Teachers still know better when it comes to using technology

More information: Mario Pandelaere, Barbara Briers, and Christophe Lembregts. "How to Make a 29% Increase Look Bigger: The Unit Effect in Option Comparisons." Journal of Consumer Research: August 2011 (published online February 1, 2011). More information: ejcr.org .

add to favorites email to friend print save as pdf

Related Stories

Categories help us make happier choices

Jul 17, 2008

Most of us have stood in a supermarket aisle, overwhelmed with the array of choices. Making those choices is easier if the options are categorized, according to new research in the Journal of Consumer Research.

Study: Many options equal extreme choices

Nov 14, 2005

Scientists in Canada and China are studying "range effect," to better understand what consumers do when faced with a range of price and quality options. Specifically, the authors found offering a wide range of options causes ...

Too many choices can spoil the research

Jun 26, 2008

The more choices people get, the less consistent they are in making those choices, according to a new study in the Journal of Consumer Research. The study's findings may affect the way researchers examine consumer choice ...

Recommended for you

Gypsies and travellers on the English Green Belt

Oct 17, 2014

The battle between Gypsies, Travellers and the settled community over how land can be used has moved to the Green Belt, observes Peter Kabachnik of the City University of New York.

Cadavers beat computers for learning anatomy

Oct 16, 2014

Despite the growing popularity of using computer simulation to help teach college anatomy, students learn much better through the traditional use of human cadavers, according to new research that has implications ...

User comments : 5

Adjust slider to filter visible comments by rank

Display comments: newest first

Eikka
not rated yet Feb 14, 2011
Depends on how you conceptualize numbers. For me, everything around the number 100 is treated as if it was a percentage of something, so I automatically translate 84 vs. 108 into "roughly 20% difference" which isn't very much.

I would be more easily fooled by 7 and 9 years of warranty.
Eikka
not rated yet Feb 14, 2011
And equally, for me the difference between 9 and 9.5 seems more significant than the difference between 90 and 95 because the former is "nine and half" and half is a lot, whereas the latter is "roughly 5% more" which is just a little.

I would probably fall for the apple-twix trick as well though, since a figure close to a 1000 is easily divided and I can immediately see that the apple is roughly 1/4th the joules, whereas 59 vs 246 would on the first glance seem like the apple is only 1/5th the calories since there's the "only 5.99" effect that masks the fact that 4 x 60 is 240.

That's why I always round prices up to the nearest full unit when shopping, or add 1 to every 9 I see to more quickly grasp how much everything is.
Joe_S
not rated yet Feb 14, 2011
see this is is exactly what i'm talking about
paulthebassguy
5 / 5 (2) Feb 14, 2011
This research confirms once again that the general population is just dumb.
Moebius
not rated yet Feb 15, 2011
And I believe that not only is $9.99 less than $10.00, it's a LOT less.

However, the authors found that the effect was not replicated when people pay close attention to specific attribute information or when people are reminded of the arbitrary nature of the unit in which information is expressed.


So when they were told they are stupid they got smarter?