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Given a plant to care for, elderly nursing home residents live longer. That simple classic experiment (1) highlights the fact that care giving - even for a potted plant - yields a health advantage.
There are some exceptions, e.g., caring for people with degenerative brain disorders, such as Alzheimer's disease. Yet, the generality that individuals who care for others on a regular basis live longer healthier lives is supported by surprisingly diverse strands of evidence, encompassing other species as well as humans.
To begin with female mammals live longer than males and also do most of the caring for youngsters. Moreover, in species where males care for offspring, they live longer, neutralizing the usual lifespan advantage of females. Such phenomena reveal the handiwork of natural selection. The females generally stick around for longer to raise their young to independence.
Being bonded to a sexual partner is another type of caring relationship. Married people live significantly longer than singles, although married men have more to gain than married women, partly because they lead healthier lifestyles as to sleep habits, alcohol consumption, diet, and reduced risk-taking. The majority of married couples also raise at least one child.
Pet ownership may also provide modest health benefits, although such research has been controversial. If even caring for a potted plant improves health, it is not hard to imagine that an emotionally responsive animal can do as much.
The intersection
All of these various examples of care giving contributing to health have at least two points of intersection. At the psychological level there is intimacy, or caring, or emotional involvement. If you are entrusted with a potted plant, you have a stake in seeing that it survives and flourishes.
At a biological level, there is the chief hormone of intimacy, namely oxytocin that plays a key role in all kinds of social relationships of vertebrates (2). Its actions range from the general effects of social touching (the cuddling hormone) to quite specific functions, including the milk let-down response, and orgasm
Oxytocin promotes calmness and relaxation with a myriad of social and health effects. It is a primary hormone involved in social bonding as revealed by experiments on voles. It is also the key to stable marriage.
Perhaps the most significant effect of oxytocin from a health perspective is that it is physiologically calming. It works as an anti-stress agent. Given that nurturant relationships involve a boost to oxytocin levels in the blood, they counteract stress hormones. In so doing, they boost immune function, helping us to fight off illness and to lead longer healthier lives.
So why should anyone care?
Science simplifies the world and that is exciting for scientists Unfortunately, non scientists are often put off by the superficial complexity and miss the blinding simplicity that underlies the long words and detailed protocols.
Buried in all of this is a very simple recipe for how we should live our lives if we want to be healthy and happy.
The recipe is illustrated by the small town of Roseto, PA, celebrated among health researchers (3). This transplanted Italian village had half the heart disease rates of the surrounding community. This had little to do with genetics because the advantage slowly disappeared as younger generations became assimilated.
The Roseto effect was due to the fact that its residents knew and cared about each other. That is a form of health insurance we could all do with.
1. Langer, E. J., and Rodin, J. (1976). The effects of choice and enhanced personal responsibility for the aged: A field experiment in an institutional setting. Journal of Personality and Social Psychology, 34, 191-198.
2. Uvnas-Moberg, K. 1998. Oxytocin may mediate the benefits of positive social interaction and emotions. Psychoneuroendocrinology 23: 819-835.
3. Barber, N. (2004). Kindness in a Cruel World (Chapter 6). Amherst, NY: Prometheus.
