Many marketers consider consumers a fickle and unpredictable lot, known to change their purchasing decisions as quickly as winds shift, without being able to say why. In part, suggest two researchers, that’s because subtle cues in the environment influence consumers without their knowledge.

How Environmental Cues Influence Product Evaluation and Choice, a January 2007 working paper forthcoming in the Journal of Marketing Research, explains how consumers’ behavior is affected by their everyday environment — cues such as writing with a pen of a certain color, or the link between pets and brands with animal associations. Jonah Berger, assistant professor of marketing at Wharton Business School, and Gráinne Fitzsimons, assistant professor of psychology at the University of Waterloo, conducted a series of field studies and experiments to determine how peoples’ product evaluations and purchase decisions might be influenced by their surroundings.

In one experiment, 29 participants completed a survey, for which each was given a pen that wrote either with orange or green ink. After a brief writing exercise to ensure that participants had seen the ink color, the participants chose which product they preferred from sets of pictures of consumer goods ranging from beverages to detergents to candy.

The results demonstrated that merely exposing participants to more of a certain color acted as a perceptual cue and led them to prefer products associated with that color: Those who wrote in orange were more likely to choose products associated with that color, such as Sunkist soda; those who wrote in green were more likely to choose a product that was green in color, such as lemon-lime Gatorade. Pen color made no difference for control sets that had neither orange nor green products.

Of course, completing a survey is a long way from actual consumption. So the researchers conducted other studies to help bridge that gap. In one field study, 59 undergraduate students were each shown one of two slogans — “Live the healthy way, eat five fruits and veggies a day,” or “Each and every dining hall tray, needs five fruits and veggies a day” — halfway into a two-week study of their eating habits. The first slogan was better liked in a pretest survey of different students. Yet those who saw the second slogan and ate in dining halls that used trays ate more fruits and vegetables in the week after they saw the slogan. “The problem with the first slogan,” says Berger, “was that there was nothing