Sometimes our perceptions of others tell us more about ourselves.

That can be true in how we interpret other people’s motivations, for example, and a newly published study suggests it can even be true in how we read people’s facial expressions.

In the study, researchers in Germany asked 50 participants to interpret pictures of people whose facial expressions displayed a mixture of happiness and sadness. Since the facial expressions were emotionally ambiguous, the researchers were interested in whether participants would project their own emotions onto the faces.

To test this idea, the researchers first asked participants to complete a series of tasks designed to elicit happy, sad or neutral feelings. These involved recalling happy or sad moments from one’s life and watching video clips of happy or sad scenes paired with appropriate music.

Participants were then asked to look at the pictures of emotionally ambiguous facial expressions and rate the emotions they saw. Looking at the ratings people provided, the researchers found a couple different factors that influenced whether people were more inclined to interpret the facial expressions as happy or sad.

As you might be expecting by this point, people who’d done the tasks designed to induce feelings of happiness were more likely to rate the facial expressions as happy compared to people who’d done the tasks designed to induce sadness. In other words, happy people also tended to see happiness in others’ facial expressions.

However, not all participants were equally likely to project their emotions onto others. In particular, people who were more inclined to take other people’s perspectives were less likely to see their own emotions in the ambiguous facial expressions. Thus, having a tendency to look at things from other’s perspectives might make people less likely to see their own emotions in others.

The researchers also looked at participants levels of what psychologists call empathic concern – how much people tend to “feel” others’ emotions or have sympathy for others. Perhaps surprisingly, empathic concern didn’t have any noticeable relationship with how likely people were to project their emotions onto others.

One explanation for that twist is that specifically the ability to look at situations through the eyes of others, but not necessarily the ability to sympathize with others’ emotions, is linked to being able to separate others’ true emotions from projections of one’s own.