A new study in the Journal of Consumer Research found that people actually salivate when they want material things, in certain situations.

"In multiple languages, the terms hunger and salivation are used metaphorically to describe desire for non-food items," writes author David Gal (Northwestern University). "But will people actually salivate when they desire material things?" Yes, they do. Gal examined, in one study, whether people salivate in response to money.

"Merely being exposed to the concept of money has been shown to have dramatic effects on behavior, and it has even been argued that money can be conceptualized as a drug in that it imitates the action of biological incentives in driving behavior," Gal writes. The experiment measured salivation by having the subjects put cotton rolls—the kind you might find at the dentist—in their mouths while they looked at pictures of money.  The cotton rolls were then measured to determine the amount of saliva.

However, before seeing the money, Gal primed the subjects to feel either powerful or powerless. "The main result of the experiment was that participants salivated to money (relative to baseline), but only when they were in a low-power state," Gal writes. "This suggests that people salivate to non-food items when those are items are desired to fulfill a highly active goal."

Second, Gal wanted to determine whether or not men salivated in response to top-notch sports cars. Yet, instead of taking note of their perceived power, he persuaded a number of the men to have a “mating goal.” Prior research, in fact, has proven that men purchase conspicuous luxury goods in part to impress women.

Naturally, Gal showed one group of men pictures of attractive women and asked them to choose the one they would like to date. Gal asked the other group to think about visiting the barber. The men that had the active mating goal salivated more at the photos of top-notch sports cars more than the men who were thinking about getting a haircut.

"Why do people salivate to money and to sports cars?" Gal asks. "One possibility is the increasingly well-established finding that all objects of desire, whether biological or non-biological, activate the same general reward system in the brain. Salivation might merely be the consequence of the activation of this general reward system."