When people in an experiment were shown two DVD players, 32% indicated they would buy one of the brands and 34% chose the other. But when the participants were shown a single DVD player, only 9% or 10% (depending on which brand they saw) said they would purchase the product, says Daniel Mochon of Tulane University. Retailers should bear in mind that consumers have an aversion to being offered just a single option, he says. Even if they can find an option they like, they may be unwilling to purchase it without considering similar options first.
Source: http://www.jcr-admin.org/files/pressreleases/072613081746_MochonRelease.pdf
Image source: http://www.skulpt.com/3d-animator-career-options.htm
More Than One Option = More Sales