Altruistic birds vs. altruistic humans

Reports the Washington Post:

A just-published study of birds reports new insights into the evolution of altruistic behavior. It suggests that sometimes the greatest beneficiaries are neither those giving or receiving alms, but those whose main job is the care and feeding of the neediest members of the population.

It is believed that about 10 percent of bird species show "cooperative breeding" behavior, in which one or more mated pairs produce chicks, which are then fed not only by the parents but by other birds sharing their territory. The helpers are usually nonbreeding males from the female's broods of the previous year - the brothers of the hatchlings they are helping to feed...

To find out what motivates this behavior, a team at the University of Cambridge in England "looked at what happened before the baby birds hatched. They compared the eggs laid by females that had helpers with those laid by solo females":

They found that fairy-wrens with helpers produce eggs with less fat, protein and carbohydrate than eggs produced by females that do not have helpers. The hatchlings of those "lite" eggs are smaller than normal chicks, but their initial scrawniness is quickly overcome by the extra food brought by the nonbreeding helpers.

The one who benefits is the mother.

Cooperatively breeding females have a 1-in-5 chance of dying over the next year, compared with a 1-in-3 chance for females without helpers. This is presumably because they are slightly healthier and stronger, having expended less energy to produce their eggs and feed their young. Their longer life span, in turn, gives them a chance to leave more offspring behind, the ultimate measure of evolutionary success.

"The mothers are stealing child care from their current young and spending it on their future young," Kilner said.

What might this say about humans? Maybe nothing. It's simply another clue in solving the mystery of why altruism exists in nature and how cooperation emerges among members of a species.

However, there are parallels with human behavior. The anthropologist Sarah Blaffer Hrdy has pointed out how cooperative child rearing has been essential at certain points in human history--for example, in hunter-gatherer societies--when fathers and adults besides the parents had to take a strong role in the care and feeding of young children. In an essay that will appear in the September issue of Greater Good, I speculate that cooperative child rearing (or alloparenting) is making a comeback in American cities, driven by the geographic and social isolation of new families, rough economic parity between men and women, and the hight cost of quality childcare.

The Way We Were vs. The Way We Are

This photo depicts the J. Bates home in Minneapolis, Minnesota in the late 1800s. Note the size of the family and the size of the porch they share. Families of this period were large, both because extended family stayed together and because children were still an economic necessity: more of them meant more hands to work in farms and shopfloors. Fathers and sons often worked side by side, and so did mothers and daughters. The economic and domestic were not separate spheres; though in the process of being eclipsed by large-scale enterprise, at this time the home economy was still America's fundamental economic unit.

As a consequence, marriage was primarily a business decision--as it had been throughout the world for thousands of years. For the lower, middle, and upper classes, people had little choice about whom to marry. Once married, they could divorce only in special or extreme circumstances. Fathers were the undisputed heads and masters of households, by both law and custom. Marital rape and wife-beating were, in most cases, perfectly legal.

Another thing to note about the J. Bates family: it is monoracial and was almost certainly monocultural. Though interracial marriage was more common than we might suppose--see Randall Kennedy's 2003 Interracial Intimacies--it was still widely condemned and illegal in many states. Nineteenth century families had more in common with previous generations than they might have with families today, but society was changing. The family as an economic unit declined; as a consequence, love rose in importance. Young people began to feel that when love dissolved, so should the marriage. Between 1880 and 1890 the divorce rate soared 70 percent.


Throughout the first half of the 20th century, people left farms and small towns for cities. Extended families fragmented and the nuclear family emerged as the dominant family form. Children became more of an economic liability than an asset; as a result, sentimental attachment to them intensified. As the century wore on, child labor was abolished and universal schooling was made mandatory. Government programs like the GI Bill educated millions of American men and increased their social mobility.

By the middle of the century, postwar prosperity made the male breadwinner and female homemaker family possible. Most men worked in offices and factories far from home; they did not take care of children. The vast majority of mothers did not work and raised kids far from from extended family. Thus mothers were isolated and many children grew up without fathers, grandparents, aunts, or uncles as stable, regular presences. By the late 1950s, middle-class women--and their children--started to rebel against isolated, retricted lives. "It took more than 150 years to establish the love-based, male breadwinner marriage," writes family historian Stephanie Coontz. "It took less than 25 years to dismantle it."


At the beginning of the 21st century, families are egalitarian, diverse, isolated, and voluntary. Where once there was no choice at all, today we have too many choices. Take a look at this 2004 photo of Brian Brantner and Matt Fuller holding their 2-month-old adopted daughter, Audrey, in San Francisco. Their family could not have co-existed with the J. Bates family in 19th century Minnesota. The gay family is, in fact, something totally new under the sun, blossoming side by side with stepfamilies, female breadwinner/male homemaker families, multiracial families, and so on. Today, only 7 percent of families fit the 1950s mold of breadwinning father and homemaking mother.

At the same time, the American economy is far less stable and social mobility has declined dramatically; class barriers are much more rigid than they are anywhere else in the developed world. This means that family is more important than ever in determining a child's chances in life. Poor children are falling behind richer counterparts, a process that starts before they even enter school. Educated parents are investing large amounts of time and money in their small number of offspring; both husbands and wives are spending more time with kids and at work, and less time with each other or in the community, which puts tremendous strain on love-based marriages.

Surveying decades of research, the sociologist Gosta Esping-Andersen writes, "What is now becoming clear is that the seeds of inequality are sown prior to school age on a host of crucial attributes such as health, cognitive and noncognitive abilities, motivation to learn, and, more generally, school preparedness." As marriages become more egalitarian, society becomes less so. We should celebrate the gains made in women's economic empowerment and male participation in domestic labor. At the same time, we should do what we can to resist rising inequality and social under-development.



Most of the photos above illustrate an article by Stephanie Coontz that will appear in the September issue of Greater Good magazine, which will focus on the relationship between the diversification of family types and the well-being of parents and children. I'm happy to provide a free copy to any blogger who promises to write about the issue. Send me an email at jeremyadamsmith (at) mac.com.