Researchers have discovered a genetic variation that may contribute to how empathetic a human is, and how that person reacts to stress. In the first study of its kind, a variation in the hormone/neurotransmitter oxytocin's receptor was linked to a person's ability to infer the mental state of others.

Rodrigues said oxytocin has already been significantly linked with social affiliation and reduction in stress. It is a peptide secreted by the pituitary gland and regulated by the hypothalamus of the brain and is best known for its role in female reproduction (it is important for labor and breastfeeding, for instance). It is also associated with social recognition, pair bonding, dampening negative emotional responses, trust, and love.