Newswise — Whether it's your favorite pizza that's only available in your hometown, or your need for a daily Facebook fix, when something becomes temporarily unavailable, does your desire for it increase or decrease over time? The answer depends on whether substitutes for those missing things are introduced. In a recent study titled "How Non-Consumption Shapes Desire," Ayelet Fishbach, Professor of Behavioral Science and Marketing at the University of Chicago Booth School of Business and co-author Xianchi Dai of Chinese University of Hong Kong, found if a person is aware of a substitute for something, the longer they have gone without, the weaker their desire for the non-consumed good becomes. So the adage "Out of sight, out of mind" is accurate. The study will be published in an upcoming issue of the Journal of Consumer Research. Conversely, when no substitute comes to mind, the longer non-consumption period suggests to a person that their need has been neglected, and their desire becomes stronger. Therefore, "Absence makes the heart grow fonder" is the fitting sentiment in this situation. "We demonstrate these effects on desire in five studies that assess various aspects of desire: feelings of missing, liking, and consumption intentions," Fishbach says. "Our findings indicate that desire is constructed: it results from a judgment people make based on the length of their non-consumption and the availability of substitutes for the original good," she adds. Implications of these research findings could turn conventional marketing wisdom upside-down. Popular marketing practice seems to suggest that desire would always increase over the length of a non-consumption period. For example, advertising and promotional efforts often start their persuasive messages by prompting the question of "When was the last time you had … ?" "Presenting this question is intended to increase consumers' craving for goods. Based on our findings, the question would be effective only when no substitutes come to the consumer’s mind and as long as the non-consumption appears outside of personal control," Fishbach says. If consumers consider substitutes for the non-consumed goods, such a strategy may backfire and negatively impact sales. "Additionally, while the marketing practice using the limited supply principle is usually effective in raising consumers' valuation and desire for product, our research suggests it may sometimes rebound. If a company restricted the supply too much, consumers could not get their much-liked products and as a consequence, would develop new tastes for substitutes and desire the product less over time," Fishbach says.