A study in the Journal of Experimental Social Psychology, suggests that we don't display our emotions that easily when we look at money:

In one of the six studies, researchers showed undergrads either ten pictures of money or of seashells (ostensibly so that they could rate the lighting and clarity of the photos), and then asked them to fill out a seemingly unrelated survey asking when it’s appropriate to keep their emotions to themselves. Those who’d seen the images of money were less likely to endorse the idea of outward emotional expression than the people who’d looked at the seashell pictures.

Other studies with similar setups showed that people with money on their minds didn’t use as many emotional words in written communication; they also were more likely to judge pictures of smiling or frowning people as more emotionally extreme. “Thinking about money increases individuals’ disposition to perceive themselves in a business-like relationship with others, in which … the expression of emotion is considered inappropriate,” the authors write. “Therefore, these individuals express less emotion in public and expect others to do likewise.”

Photo credit: Aotearoa Adventures