Giving Love and Support to Others Could Help You Live Longer
Taking care of someone may lower caregivers' mortality rates, study finds.
Posted December 24, 2016
Taking care of people within—and beyond—your immediate family is associated with longer life expectancy for the caregiver, according to a new international study. The researchers used an evolutionary framework combined with a longitudinal aging study to examine whether engaging in prosocial behaviors towards both kin (biological relatives) and non-kin helped older adults stay healthier and live longer.
Based on the correlative evidence, the researchers concluded that caregiving within and beyond the family is associated with lower mortality for caregivers. The findings were published this week in the December 2016 journal Evolution and Human Behavior.
The researchers analyzed data from over 500 people aged between 70 and 103 years, who had participated in the Berlin Aging Studies (BASE) collected between 1990 and 2009. The collaborative study on the benefits of caregiving was conducted by researchers from the University of Basel, Edith Cowan University, the University of Western Australia, the Humboldt University of Berlin, and the Max Planck Institute for Human Development in Berlin.
While analyzing the life expectancy data from BASE, researchers were intrigued to find that mortality rates for grandparents who participated in 'non-custodial childcare' of their grandchildren had a much lower rate of mortality than grandparents who did not provide childcare. This discovery corroborated what is known as the grandmother hypothesis. The association between caregiving and longevity were constant after controlling for physical health, age, socioeconomic status, and various characteristics of the children and grandchildren.
Notably, the life-extending benefits of caregiving were also observed in non-grandparents and adults without children who helped others within the community beyond their families.
In a statement to University of Basel, first author Sonja Hilbrand, doctoral student in the Department of Psychology said,
“It seems plausible that the development of parents’ and grandparents’ prosocial behavior toward their kin left its imprint on the human body in terms of a neural and hormonal system that subsequently laid the foundation for the evolution of cooperation and altruistic behavior towards non-kin.”
The "grandmother hypothesis" was formulated in the 1980s after Kristen Hawkes and James O'Connell had spent time living amongst the Hadza hunter-gatherers of north-central Tanzania. The researchers observed that most older women in the society spent their days gathering tubers and other food for their grandchildren and other youngsters within the tribe. Hawkes and her colleagues developed a groundbreaking 'grandmother theory' based on the notion that humans may have evolved to live longer lives because grandmothers were inherently proactive about helping to take care of her children's offspring.
The grandmother hypothesis also proposes that by taking responsibility for gathering food for her daughter's grandchildren, each daughter is able to have more children, more quickly. This hypothesis suggests that the most evolutionarily fit grandmothers will have the most grandchildren, thus passing on their longevity-promoting genes to more robust offspring in the next generation.
The Evolutionary Biology of Altruism and Kin Selection Theory
In 1975, Harvard biologist Edward O. Wilson published his seminal book, Sociobiology: The New Synthesis, which offered a revolutionary perspective on evolution. Wilson hypothesized that certain types of prosocial behaviors—including altruism and caregiving—might be genetically hardwired into a species to help that species proliferate and avoid extinction. In the late-twentieth century, Sociobiology was considered the most significant contribution to evolutionary theory since On the Origin of Species by Means of Natural Selection by Charles Darwin.
Darwin’s theory of natural selection was based on the concept of “survival of the fittest." Through the lens of modern-day achievement, this theory implied that in a cut-throat and competitive dog-eat-dog world that every individual must claw his or her way to the top of the ladder. From an evolutionary perspective, natural selection didn't factor in the importance of cooperation or a biological need to "tend-and-befriend" in order for an individual or species to survive and thrive.
Darwin’s natural selection theory didn't make cooperation or altruism a part of the equation. E.O. Wilson saw this omission as an inaccuracy and tried to resolve the paradox that only the strong survived by creating a hypothesis he called “kin selection theory.”
According to kin selection theory, altruistic individuals would take care of their kin and prevail because the genes that they shared with kin would be passed on, which echoes the idea of the grandmother hypothesis. Because the whole clan is included in the genetic victory of a few members, the evolutionary phenomenon of beneficial altruism came to be known as “inclusive fitness” as opposed to simply “survival of the fittest.”
By the 1990s the concept of inclusive fitness and kin selection theory had become a fundamental aspect of evolutionary psychology and the anthropological explanation of altruism and prosocial behaviors. However, in 2010, Wilson rocked the boat with the announcement that he no longer endorsed the kin selection theory he'd spent decades researching and proselytizing. Along with two colleagues at Harvard, he published a study, "The Evolution of Eusociality" in the journal Nature. This caused a big stir in academia and anthropological circles.
Wilson acknowledged that according to kin selection theory, altruism only arises when the "giver" has a genetic stake in the game. But after a complex and advanced mathematical assessment of the natural world, Wilson and his colleagues had discovered that altruism evolved for the good of the community rather than just for the good of someone’s individual genes. As Wilson puts it, “Cooperating groups dominate groups who do not cooperate.” Altruism, and looking out for the well-being of others, appears to protect entire social groups whether or not they are blood relatives or kin.
Wilson and colleagues concluded, “We may be the only species intelligent enough to strike a balance between individual and group-level selection, but we are far from perfect at it. The conflict between the different levels may produce the great dramas of our species: the alliances, the love affairs, and the wars.”
Evolutionary Anthropologists Agree: Human Beings Must Cooperate to Survive
In November of 2012, Wilson’s new theory was corroborated by Michael Tomasello and researchers in the Department of Developmental and Comparative Psychology at the Max Planck Institute for Evolutionary Anthropology who developed their own new theory called the
"interdependence hypothesis." Tomasello's research offered an explanation as to why humans are much more inclined to cooperate with one another than our closest evolutionary relatives. Their findings were published in the journal Current Anthropology.
Tomasello et al. hypothesized that humans developed cooperative skills because it was in their mutual interest to work well with others. Especially when practical circumstances forced them to cooperate with others to obtain food. Evolutionary anthropology suggests that being altruistic isn't the reason we cooperate; we must cooperate in order to survive, and therefore, we are altruistic towards others because we ultimately need them for our individual survival.
The authors speculate that at some point in our evolution, it became necessary for humans to forage together, which meant that each individual had a direct stake in the welfare of his or her local community. Individuals who were able to coordinate well with their fellow foragers—while also pulling their own weight within the group—were most likely to succeed individually and collectively.
In this context of interdependence, humans evolved special cooperative abilities that other apes do not possess, including dividing the spoils fairly, communicating goals and strategies, and understanding one's role in the joint activity as equivalent to another's.
As societies grew in size and complexity, their members became even more dependent on one another. Modern theories of cooperative behavior and interdependence suggest that acting selflessly provides a selective advantage to the altruist in the form of various types of tangible and intangible rewards in return for your kindness.
Dolly Parton Is a Role Model of Altruism and Group-Minded Interdependence
From a perspective of evolutionary anthropology, caregiving, and longevity—Dolly Parton may seem like an atypical role model and case study. But her recent telethon to raise millions of dollars to help everyone who lost their homes in the recent Tennesse wildfires put her altruism and commitment to interdependence in the national spotlight.
Parton's close-knit bonds to her local community go far beyond her blood relatives. Her commitment to help others extends to everyone she considers family living in the Smoky Mountains, as well as children around the globe.
In a heartwarming interview, Dolly Parton recently explained why she is raising money for all those who lost their homes in the wildfires that ravaged Sevier County, Tenn. last month. This transcript captures the life-affirming power of prosocial behaviors and doing your part to take care of those you consider family whether or not they're technically kin. Dolly Parton said,
“I would have never imagined anything like this happening to our beautiful Smoky Mountains. This is the most devasting thing that we've all experienced... It's personal for me to help the people in the wildfires because that's my home. These are my people. These are neighbors, these are people I grew up with... Even though they might not be blood-kin, they're still my family, they're still my people.
We're going to do everything to help everyone who has been affected by these wildfires. I would have dropped anything to help. It's just like when a family member is sick or having trouble. That's how I feel about this. . . These are the people that need me now. And I'm in a position to help. I'm willing to do anything and everything that I can do to help.
Anytime there's devastation it's bad enough. But having something like this happen around the holidays—around Christmas-time is especially bad. It's a time when you're supposed to be joyful. To be with family and be in your cozy house and cooking all that food....and doing all those wonderful things. But now, so many people aren't going to have that kind of Christmas.
So, it makes it twice as bad that it's happened this time of year. For all the people out there that would still like to help. You can reach us through the DollywoodFoundation.org. I would appreciate anything and everything that anybody can do. Whether you give a little money, or a lot. Anything will help."
Parton’s “My People Fund” has raised almost 10 million dollars and is planning to donate $1,000 each month (for up to six months) to every family left homeless by the Tennesse wildfires. Below is a YouTube clip of Parton's interview transcribed above:
For decades, Dolly Parton has dedicated herself to philanthropic ventures that help and support people of all ages and walks fo life. For example, her nonprofit "Imagination Library" delivers over a million books each month to school-age children around the world. Parton's altruism and prosocial behaviors embody the phrase "Think Globally, Act Locally." She's also living proof of the uplifting power of helping others as a way to help maintain your own well-being and increase your longevity.
At 70+ years of age, Dolly Parton is going stronger than ever. A few weeks ago, she gave a rousing performance of “Jolene” alongside her goddaughter, Miley Cyrus, and Pentatonix on The Voice. Clearly, Dolly Parton is still at the top of her game and perpetuates a contagious sense of purpose by being able to help take care of people within and beyond one's blood-kin family.
Interdependence 101: When You Help Others, You're Also Helping Yourself
From an anthropological perspective, the latest empirical evidence suggests that we've evolved to live longer lives as a result of our ability to take care of one another.
During these topsy-turvy times, when the zeitgeist seems to reward being non-cooperative, nepotism, and using Twitter as a bully pulpit to rise to the top of the food chain...the science of evolutionary anthropology serves as a grounding reminder that taking care of your family, friends—as well as a broader community—benefits both the receiver and the caregiver over the long haul.
Obviously, the spirit of giving shouldn't be reserved just for the holidays. Being altruistic and lending a hand is something each of us can do in small ways 365 days a year. That said, anytime you feel a wave of self-serving narcissism or Machiavellian tendencies creeping in, remember: When you help others, you're also helping yourself.
We're all in this together. Living by the evolutionary rules of group-minded interdependence creates a win-win for all parties involved and avoids the pitfalls of zero-sum relationships. Hopefully, the combination of scientific data and real-world anecdotal evidence presented herein reinforces what you already know about the personal benefits of being generous, altruistic, and taking care of others throughout the year.
Sonja Hilbrand, David A. Coall, Denis Gerstorf, Ralph Hertwig. Caregiving within and beyond the family is associated with lower mortality for the caregiver: A prospective study. Evolution and Human Behavior, 2016; DOI: 10.1016/j.evolhumbehav.2016.11.010
Tomasello, M., Melis, A., Tennie, C., Wyman, E., & Herrmann, E. (2012). Two Key Steps in the Evolution of Human Cooperation: The Interdependence Hypothesis. Current Anthropology, 53(6), 673-692. DOI: 10.1086/668207
Hawkes, K., J. F. O'Connell and N. G. Blurton Jones. 1989. Hardworking Hadza grandmothers. In Comparative Socioecology: The Behavioural Ecology of Humans and Other Mammals, edited by V. Standen & R.A. Foley, pp. 341-366. London: Basil Blackwell. Published, 06/1989
Martin A. Nowak, Corina E. Tarnita, Edward O. Wilson. The evolution of eusociality. Nature, 2010; 466 (7310): 1057 DOI: 10.1038/nature09205