Dr. Kai MacDonald of the University of California, San Diego School of Medicine says oxytocin is a brain chemical associated with pair bonding, including mother-infant and male-female bonds and increased paternal involvement with children.

"That's why oxytocin is sometimes called 'the love hormone,'" MacDonald in a statement. "It's said that the eyes are the window to the soul ... they certainly are the window to the emotional brain. We know that the eye-to-eye communication -- which is affected by oxytocin -- is critical to intimate emotional communication for all kind of emotions -- love, fear, trust, anxiety."

People with schizophrenia or autism often avoid eye-to-eye gaze, focus on less relevant areas of the face, and avoid meaningful social contact. The researchers theorize that oxytocin might act on the brains of patients with schizophrenia and anxiety and may ultimately increase the level of trust or emotional contact between patient and physician, or with patients and significant others.