Modern Darwinism conspires with Machiavellian politics and competition-based economics to paint a very cynical picture of human nature. Such theories have their uses but modern psychology suggests that they are wrong about people. We are learning that humans do best when they care for others rather than looking out for themselves.

Caring for others promotes well-being and health. That conclusion violates crude Darwinian ideas about natural selection of competitive tendencies. Yet, successful reproduction requires a huge investment from human parents, just as is true of cooperative breeding in birds. This is one plausible mechanism through which a propensity to care for others might have evolved.

That people are predisposed to care about, and care for others is surprising to no one outside the academic world. Yet, the idea that caring for others actually improves our health, and even our sanity, has unfolded slowly in the past two decades. Social psychologists were early to the topic finding that a seemingly ridiculous minimal exercise in caring for others boosts health. I refer to celebrated experiments in which elderly residents of nursing homes were asked to care for potted plants.

Love and the potted plant

The Rodin and Langer studies (1) found that caring for a potted plant substantially reduced mortality amongst nursing home residents. This finding is backed up other research on the beneficial effects of caring for plants. The movie Greenfinger recounts the true story of a hard-nosed group of English prisoners whose involvement in a garden project rehabilitated them into honest society (2).

Perhaps there is something uniquely restorative about horticulture. More likely, involvement in such programs taps into a more general human tendency towards nurture that is based on our evolutionary niche as cooperative breeders tasked with getting children through the long and dangerous period of childhood dependency.

I suspect that the polarized work roles of women and men since the Industrial Revolution contributed to the false stereotype that men are providers whereas women are nurturers. That hunch is based on what we are gleaning about the evolutionary biology of caring for others.

Evolution and nurture

In an earlier post, I presented evidence that nurturing behavior improves health and well being thereby contributing to length of life. Nurturers live longer, possibly because their health and longevity contribute to raising young who are better at surviving and reproducing.

Primates are particularly interesting here. If females do most of the nurturing, they live substantially longer than the males. Conversely, if the males spend a lot of time caring for the young, they can live as long as females (as illustrated by siamangs and titi monkeys, 3).

The greater longevity of caretakers may be due to the fact that they continue to be useful to offspring for a long time after they are born so that long livers have more progeny that survive to maturity. In other words, natural selection favors long life for caretakers.

The precise mechanisms are of great interest to health researchers because they offer clues as to how we might slow aging and extend human life. One mechanism that has received considerable empirical support is the positive impact of oxytocin – the “cuddling hormone” on health and longevity.

The cuddling hormone and health

When distressed, young mammals can have a plaintive, even obnoxious cry that motivates the caretaker to soothe their distress. Anyone with a teething infant knows that they are good at spreading the pain around! In the process of soothing an infant, the caretaker is soothed also and their empathic distress gets neutralized.

Interestingly, much of the calming impact of close social interactions is attributable to oxytocin – the cuddling hormone. Moreover, this single hormone is the most plausible explanation for the health benefits of intimate social interactions (4). So it helps explain why care givers are healthier and live longer.

Mothers release more oxytocin when they tend to infants so that they experience a direct health benefit from the interaction. Oxytocin also plays an important role in the physiology of both breast feeding and orgasm.

This would appear to leave fathers out in the cold. Initial research suggested that men did not have an oxytocin response to their infants. Yet, more recently as fathers took the job of primary caregivers, they evinced the same oxytocin response as mothers. May they also be rewarded with long life!


1. Rodin, J., and Langer, E. J. (1977). Long -term effects of a control-relevant intervention with the institutionalized aged. Journal of Personality and Social Psychology, 35, 897-902

2. Barber, N. (2004). Kindness in a cruel world. (Chapter 6). Amherst, NY: Prometheus.

3. Allman, J., et al. (1998). Parenting and survival in anthropoid primates: Caregivers live longer. Proceediongs of the National Academy of Sciences, 95, 6866-6869.

4. Uvnas-Moberg, K. (1998). Oxytocin may mediate the benefits of positive social interactions and emotions. Psychoneuroendocrinology, 23, 819-835.

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