In public speaking class, we were taught to make eye contact with our audiences. You're supposed to stare deep into their eyes, connect, and convince them of what you're saying.

But new research suggests that unless you're having a friendly conversation, staring into someone else's eyes might be the total opposite of what you should do to be persuasive.

According to a study from the University of British Columbia, the University of Freiburg in Germany, and the Harvard Kennedy school, locking eyes with someone discussing controversial views actually made the listener less likely to be persuaded by the speaker's argument.

The study used remote eye-tracking to record where the subjects (20 university students working for course credit) were looking as they watched several videos featuring people talking about controversial issues like assisted suicide, factory farming and nuclear energy. At the end of each video, the participants were asked how they felt toward the arguments made int he video and how they felt about the viewpoints expressed by the speaker.

Researchers found that subjects spent more time looking into the eyes of the speaker when they already agreed with the arguments the speaker was making.

Another experiment involved researchers showing a different set of students videos of people speaking about the same issues, but participants only saw videos arguing for a position researchers knew they disagreed with. Students who were instructed to look at the speaker's eyes the whole time were less likely to be persuaded by the argument than those who spent the video's duration looking at the speaker's mouth.

The findings suggest that perhaps in more dire situations, an argument for example, eye contact might be associated with dominance or intimidation, rather than a sign of connection like in friendly situations. Researchers also note that different cultures use eye contact differently.

Researchers plan to study whether there are physiological changes associated with eye contact, like an increase in heart rate or release of stress hormones. "Eye contact is so primal that we think it probably goes along with a whole suite of subconscious physiological changes," lead author Frances Chen said.