Patients also gave doctors higher empathy scores when their total visit length was longer and when doctors engaged in a few "social touches" such as a handshake or pat on the back. However, more than three social touches in one visit decreased empathy scores. The researchers said it's possible that too many social touches from a doctor may seem forced and not genuine to a patient.

The study, published in the Journal of Participatory Medicine, analyzed videotaped doctors' visits and reinforces the notion that nonverbal social communication is an important part of doctor/patient relationships that should be thoughtfully managed, especially as more technology and "screen time" is introduced into doctors' offices.

"The goal is to one day engineer systems and technologies that encourage the right amount of physician eye contact and other non-verbal social communication," said Enid Montague, first author of the study. "As we collect more data we can build models that tell us exactly how much eye contact is needed to help patients trust and connect with a doctor, and design tools and technology that help doctors stay connected to patients."

Montague is an assistant professor in medicine, general internal medicine and geriatrics at Northwestern University Feinberg School of Medicine and an assistant professor in the McCormick School of Engineering and Applied Sciences.

The researchers collected data from 110 first-time encounters between patients with common cold symptoms and primary care doctors. All of the doctors used paper charts and spent an average of 3 minutes and 38 seconds with each patient. After each visit, patient participants completed questionnaires to measure their perception of their doctor's empathy, connectedness with the doctor and how much they liked their doctor.

The visits were videotaped and researchers analyzed the recordings second-by-second, documenting what each person was doing, paying special attention to non-verbal communication. The researchers purposely chose to study doctors who used paper charts so they could develop a baseline for nonverbal communication activities without the presence of computerized systems.

"Previous studies have found that nonverbal communication is important based on patient feedback, but this is one of the few that have looked at these things more broadly quantitatively," Montague said. "We rigorously looked at what was happening at every point in time, so we validated a lot of the qualitative studies."

They concluded that while social touch and length of visit can play a role in a patient's perception of doctor empathy, the amount of eye contact the doctor made was the most important factor for patients.

"Simple things such as eye contact can have a big impact on our healthcare system as a whole," Montague said. "If patients feel like their doctors aren't being empathetic, then we are more likely to see patients who aren't returning to care, who aren't adhering to medical advice, who aren't seeking care, who aren't staying with the same providers. If they switch providers, that's very costly for the healthcare system."