We’ve all said it, or heard it before: "I’m wary of emailing because someone might misread my tone".

It’s true.  Think about it.  A work colleague sends an email that closes with "Don’t work too hard".  Is he being friendly, or sarcastic?

A recent study shows that your interpretation of that email will be correct about half the time.

"That’s how flame wars get started," says psychologist Nicholas Epley of the University of Chicago, who conducted the research with Justin Kruger of New York University. "People in our study were convinced they’ve accurately understood the tone of an e-mail message when in fact their odds are no better than chance," says Epley.

The researchers took 30 pairs of undergraduate students and gave each one a list of 20 statements about topics like campus food or the weather. Assuming either a serious or sarcastic tone, one member of each pair e-mailed the statements to his or her partner. The partners then guessed the intended tone and indicated how confident they were in their answers.

Those who sent the messages predicted that nearly 80 percent of the time their partners would correctly interpret the tone. In fact the recipients got it right just over 50 percent of the time.

"People often think the tone or emotion in their messages is obvious because they ‘hear’ the tone they intend in their head as they write," Epley explains.

At the same time, those reading messages unconsciously interpret them based on their current mood, stereotypes and expectations. Despite this, the research subjects thought they accurately interpreted the messages nine out of 10 times.

Why do we get email messages wrong?  Because, according to the researchers, we’re selfish pricks:

The reason for this is egocentrism, or the difficulty some people have detaching themselves from their own perspective, says Epley. In other words, people aren’t that good at imagining how a message might be understood from another person’s perspective.

Instinctively, I think regular email users already know this.  But it’s nice to know that science has backed us up.