If you’re looking to give your dry work emails some personality, sprinkling in emojis may not be the smartest strategy. As Mashable reports, smiley emojis in professional correspondences rarely convey the sentiments of warmth that were intended. But they do make the sender come across as incompetent, according to new research.

For their paper titled "The Dark Side of a Smiley," researchers at Ben-Gurion University of the Negev in Israel looked at 549 subjects from 29 countries. After reading emails related to professional matters, participants were asked to judge the "competence and warmth" of the anonymous sender.

Emails that featured a smiley face were found to have a "negative effect on the perception of competence." That anti-emoji bias led readers to view the actual content of those emails as less focused and less detailed than the messages that didn’t include emojis.

Previous research has shown that sending emojis to people you’re not 100 percent comfortable with is always a gamble. That’s because unlike words or facial expressions, which are usually clear in their meanings, the pictographs we shoot back and forth with our phones tend to be ambiguous. One study published last year shows that the same emoji can be interpreted as either positive or negative, depending on the smartphone platform on which it appears.

Fortunately, there are plenty of ways to communicate effectively without leaning on emojis to make you look human. Here are some etiquette tips for making your work emails sound clear and competent.

[h/t Mashable]