One behavior that is a likely candidate is hugging. Hugging is a likely candidate because nonsexual physical contact is a communication of reassurance, care, and empathy. This type of behavior is linked with better immune functioning within both human and non-human primate families and communities. So, the question that emerges is:
To answer this question, an interdisciplinary group of researchers, led by Dr. Sheldon Cohen at Carnegie Mellon University conducted a study on 404 healthy adults (age 33). In this study, each participant completed a questionnaire about their perceived social support and participated in a physical exam that included a blood test for antibodies and measurement of their mucus to assure they were not sick. Each participant then completed an interview every day for 2 weeks where they reported on what they did that day, who they interacted with, whether they experienced any conflicts, and whether they received any hugs from anyone. At the end of the two weeks, they completed another physical exam and blood test to measure the presence of antibodies. Then each participant received nasal drops of the common cold (rhinovirus 39) or the flu (influenza A/Texas/39/91). For up to 6 days following exposure to the cold or flu, participants were assessed for the development of cold and flu symptoms, and then were assessed again 4 weeks after exposure to the illness.
Cohen and his team found that 78% of participants in this study contracted the illness they were exposed to (as measured by developing some symptoms), and that 31% developed a clinically significant illness of either the flu or the cold. They also found that people in this study were exposed to hugs 67% of the 14 days, while conflict was only reported on about 7% of the 14 days. The main finding of the study was that participants who reported more conflict during the 14 days preceding exposure to the flu/cold were more likely to develop an infection, however receiving more hugs served as a buffer to that effect. Thus, they found that hugs were an effective, protective experience that prevented the cold/flu.
In particular, their findings suggest that hugs are more helpful in improving immunity to the cold, rather than the flu. This may have to do with the rate that the flu replicates in the body. They also found that hugs were protective in whether or not the participant would get sick, not necessarily how sick they would get. Remember, they drew a distinction between people who developed symptoms (78%) and people who had clinically significant syndromes (31%). Hugs were effective in buffering the link between having conflict and developing symptoms, but were not necessarily effective in preventing the severity of the illness if you do contract the infection. To me, this suggests that, not surprisingly, there is more to immunity than hugs, and there are still individual differences in the ways our bodies respond to exposure to germs and viruses.
Of course, this research doesn’t suggest that we should just go around hugging one another instead of going to the doctor to get a flu shot. Rather, giving hugs to our loved ones frequently, especially if they are going through stress is an effective way to provide social support that may boost immunity.
Despite this important and fascinating potential benefit, there are several questions that emerge from this study about application and potential explanation. For example, do people who give and get hugs frequently simply have more efficient immune systems because they consistently have more exposure to germs and bacteria? I wonder whether we could test that question by comparing immunity across cultures who vary in their typical greetings, for example bowing (no physical contact), shaking hands, kissing on both cheeks. Or, is there something special about a hug that improves immunity through psychological well-being like optimism that people care about you?
Another potential limitation of this study was that conflict was reported fairly infrequently in this sample, only 7% of days (less than 1 day on average). I wonder whether these effects would be stronger or weaker among a sample with more frequent exposure to conflict, such as people exposed to domestic violence, or who deal with conflict as part of their job, such as attorneys.
To conclude, this article is just one more example for me of how we can benefit from taking care of ourselves by showing that we care for one another. I’ve always been a bit reluctant around those enthusiastic groups of people around town squares waving FREE HUGS signs. Now, I have a greater appreciation for the work that they do for public health. More free hugs for everyone!
Cohen, S., Janicki-Deverts, D., Turner, R. B., & Doyle, W. J. (2014). Does Hugging Provide Stress-Buffering Social Support? A Study of Susceptibility to Upper Respiratory Infection and Illness. Psychological science, 0956797614559284.