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Tuesday, September 4, 2012

84 months vs. 7 years

Do you consider yourself as someone who cannot be manipulated without consciously being aware of it?  Can something as simple as changing the scale from 1-10 to 100-1000 have an effect on you?  A recent study shows that it certainly can (How to Make a 29% Increase Look Bigger: The Unit Effect in Option Comparisons. Author(s): Mario Pandelaere, Barbara Briers, Christophe Lembregts. Source: Journal of Consumer Research, Vol. 38, No. 2 (August 2011), pp. 308-322).  The choice of units when presenting quantitative information can have profound effects on your perceptions, choices, and preferences.

The authors of this study make several observations that they continue to support with experimental data.  The authors find that consumers tend to focus on the "the number rather than the type of units in which information is expressed."  In other words, if you present information on two choices using months and years, your average viewer is much more likely to notice the number of months and years instead of the fact that one choice is represented with months and the other choice is represented in years.  By focusing primarily on the number, rather than the unit, the viewer mistakenly believes that the difference between two choices is actually much larger than it actually is.  For instance, when judging the difference between 20 tons and 25 tons, and 40,000 pounds and 50,000 pounds, the viewer will mistakenly believes that the difference in the 40,000-50,000 case is greater than the difference in the 20-25 case, even though the difference is exactly the same.  The fact that one example uses bigger values tends to throw off mental calculations because viewers are looking at the numbers in absolute terms and ignoring the units involved.

In another example, "people incorrectly believe cancer is riskier when statistics report that it affects 1286 of every 10,000 persons than when they report that it causes the death of 24.1 per 100 persons." Consequently, as numbers get larger, quantity differences are perceived to be greater than they actually are.  When perceptions are affected, there are real consequences in people's behavior, perceptions, and choices.

To test their hypotheses, the authors conducted 4 different studies where they increased the scale of the units involved. For instance, in one of their studies, the authors presented the study participants with information on calories.  The two groups of participants were given the choice of an apple or a Twix bar.  With the first group of participants, the calorie information on both food items was presented in Kilojoules, which resulted in greater calorie quantities in absolute terms.  With the second group, information was presented in Kilocalories, which resulted in smaller quantities in absolute terms. The authors found that "participants were more likely to choose the apple in the kilojoules condition compared to the kilocalories condition" at statistically significant levels (p=.03).  The apple became a more popular choice because the participants believed it had a high energy content in absolute terms. Across all studies, the authors found statistically significant results that are consistent with initial hypotheses.

 The authors' findings can be applied in ways that promote consumers to engage in more environmentally sustainable behavior.  For instance, what if a local city council is trying to urge citizens to conserve and create less waste?  The local officials can apply this study's findings  when using statistics to show how much waste an average household in the city generates per year.  The waste amount can be listed in smaller units to make the problem seem bigger and more important.  For instance, when waste statistics at the city level are being presented, pounds can be used as the units of measurement instead of tons.  A resident seeing "500,000 pounds" might be more prone to being persuaded than seeing "250 tons."  Much like in the cancer statistic example, the waste problem can be perceived as more severe if the information is presented in units that make the problem seem bigger in absolute terms.  Once perceptions are affected, behavior will be easier to change.

Ultimately, the authors' findings can be used in many other contexts to promote beneficial behavior.

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