Carnegie Mellon psychologist Sheldon Cohen has shown that people who report an abundance of positive emotions in their lives are less likely to develop a cold when exposed to the virus--and report fewer symptoms if they do.
Cohen had published a similar paper in 2004 which however left open the possibility that associated characteristics such as extroversion and optimism could have affected the results. His most recent report, to be published in this month's Psychosomatic Medicine, these variables are controlled while the same outcome was observed.
Read more: Happy People Are Healthier, Carnegie Mellon Psychologist Says