CHICAGO (CBS) — How much eye contact did your doctor make with you at your last appointment? A new study by a Chicago researcher suggests the more eye contact, the more you like your doctor.

WBBM’s Steve Miller reports researchers with Northwestern Medicine videotaped about 100 patients and 10 doctors during examinations at clinics in the Midwest.

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“We found that eye contact was really important for perceptions of empathy, so physicians that made more eye contact with their patients tended to be rated as more likable and empathetic,” said assistant professor Enid Montague, who authored the study. We also found that social touch – such as handshakes and pats on the back – also positively affect perceptions of empathy.”

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However, Montague said too much touching is a bad thing. The study found if a doctor pats a patient’s back more than three times, it’s seen as insincere, or perhaps creepy.

“That was something that was really interesting to us,” she said. “There’s a limit. If you don’t make any social touches, there’s negative consequences. The optimal amount is around three. Three handshakes. Three pats on the back. But over that and empathy scores tend to decrease.”

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She said the study found younger doctors are less likely to make eye contact than older doctors.