In a new study from the August issue of the Journal of Consumer Research, researchers from Northwestern University demonstrate how advertisements can be manipulated to cause overemphasis of a particular feature and increase the likelihood that a certain product is chosen. Their finding runs contrary to economic models, which assume that choices are based on stable preferences and should not be influenced by the inclusion of inferior options.

"By showing the impact of perceptual focus on consumer preferences, this research demonstrates that in addition to the many overt ways companies can draw attention to products, the visual arrangement of alternatives can also have a significant influence on their relative choice shares," explain Ryan Hamilton, Jiewen Hong, and Alexander Chernev.

In a series of fascinating experiments, the authors show how grouping together options with similar characteristics can emphasize dissimilar options and help them pop-out. For example, consider a comparison of two sofas, A and B. Sofa A has softer cushions; Sofa B is more durable. In a head-to-head comparison, sofa A is preferred by less than half of the survey participants - 42.3 percent.

However, if sofas A and B are grouped with three other sofas, all of which have a low rating for cushion softness, then preference for sofa A jumps to 77.4 percent. One of these things is not like the others, and that apparently makes it more desirable - a phenomenon the authors term "perceptual focus effect."

"The research presented in this article has practical implications for manufacturers and retailers in determining the size and composition of their product assortments," conclude the authors. "In particular, when designing product displays, in both print and electronic media, companies need to be aware of the potential impact of the visual characteristics of choice alternatives on consumer preferences."

The researchers also found that how consumers process information can influence how susceptible they are to perceptual focus effect. Those who rely on intuition are more likely to choose a perpetually focal option. In addition, having participants perform an analytical test before making a product choice drained logical reasoning resources and increased the likelihood that the person would choose the perpetually focal option.