*Marketers at Virginia Tech share stealthy new ways to control how people perceive numbers that go far beyond simple psychological pricing.*

Retailers almost never round up because of psychological pricing, the old marketing rule that dictates that consumers are more easily swayed by prices that end with ".99" because they seem substantially cheaper.

This week on *Professional Help*, discover five more nuanced ways proprietors, politicians, and public relations professionals may be using numbers to influence your perceptions and behavior. Based on classic numbers texts as well as their own forthcoming *Journal of Consumer Research* paper, Virginia Tech marketers Rajesh Bagchi and Derick F. Davis break down the complexities of numbers psychology, from the significance of number size and unit choice to how even your own culture, mood, and mathematical abilities may be used against you.

**Size matters.** The basic finding in numbers research is called numerosity, and it refers to people's tendency to infer larger sizes or "more" of something from larger numbers. To downplay a 30-day service penalty, therefore, simply referring to it as a one-month suspension might help. Conversely, bigger numbers should be used to convey increases in nutritional benefits (1,000 milligrams of fiber, not one gram) or cellphone talk time (660 minutes, not 11 hours) to make people feel as though they are getting better deals.

**Units matter.** People may sometimes rely more on units than numbers to make judgments. For example, since conversational norms dictate that small quantitative changes be disclosed using small units like days and large changes be conveyed via large units like weeks, people may perceive weeks as a greater unit than days, regardless of the number attached to it. A two-week change may seem longer than a 14-day change, for instance. This effect, called unitosity (PDF), occurs in contexts that are more abstract or future-oriented. Consumers may pay more attention to units when evaluating longer-term loan payments, for example, so an additional payment over 180 months may appear easier to manage than one over 15 years.

**Order matters.** We give much higher estimates for the value of 4 factorial (4!) when it's expressed as 4 x 3 x 2 x 1 vs. 1 x 2 x 3 x 4 (PDF) because we "anchor" our perceptions on the first multiplication result (12 > 2) or the first number (4 > 1). Because of this, the order in which the package's cost and the number of items in the package are presented can influence perceptions. When the larger benefit is presented before the price (e.g., "70 items for $29"), consumers find the package more appealing than when the price is presented first (e.g., "$29 for 70 Items"). The temptation to present price first may be strong, but our research finds no evidence that mentioning price first is inherently advantageous.

**Calculation difficulty matters.** When people find it hard to do the math, they rely on heuristics or shortcuts that are highly susceptible to numerosity, unitosity, and order influences. They will believe that unit prices are lower in a "70 items for $29" package over one billed as "$0.41 per item," even though the unit prices are identical (PDF). However, assessments of unit prices in a package billed as "50 items for $20" will not differ from one presented as $0.40 per item, as it is easier to compute and be objective. Thus, to trigger the biases mentioned above, try making any calculation slightly more complicated. If facilitating good decision-making is the objective, though, simplifying computations is the clear choice.

**Combinations of the above matter.** This final tip is a cautionary one. A complete picture of how all the aforementioned variables interact with one another is still coming together. The relative influence of numerosity, units, order, and calculation difficulty depends on decision contexts, individual mindsets, cultural conventions, and mathematical competencies, among other variables. This much we do know, however: We need to be aware of these factors when deciding how to communicate numbers and how to take them in.

*Image: Sychugina/Shutterstock.*

This article available online at:

http://www.theatlantic.com/health/archive/2012/02/professional-help-5-ways-youre-influenced-by-numbers-psychology/251906/