I’ve often wondered why women in wealthy societies have fewer children. Melanie Moses (who teaches Computer Science at the University of New Mexico) offers a solution in an article entitled, “Being Human: Engineering: Worldwide Ebb,” appearing in the 2/5/09 edition of Nature (available online only to subscribers). This phenomenon is counter-intuitive because evolution by natural selection would seemingly predict that human animals with more resources would have more babies. Moses employs the Metabolic Theory of Ecology (MTE), an approach for understanding the dynamics of flow through networks. It was developed
to explain why so many characteristics of plants and animals systematically depend on their mass in a very peculiar way. . . According to the theory, the larger the animal, the longer its cardiovascular system (its network of arteries and capillaries) takes to deliver resources to its cells. That delivery time, which in turn dictates the animal’s metabolic rate, is proportional to the animal’s mass raised to the power of ¼. Thus, because its circulatory system works less efficiently, an elephant grows systematically more slowly than a mouse, with a slower heart rate, a lower reproductive rate and a longer lifespan.
Moses argues that this idea that networks become predictably less efficient as they grow has “profound” consequences. With regard to fertility, she starts with facts regarding our energy consumption.
The average human uses up only about 100 watts from eating food, consistent with predictions based on body size. But in North America, each person uses an additional 10,000 watts from oil, gas, coal and a smattering of renewable sources, all of which are delivered through expansive, expensive infrastructure networks.
How do energy networks interact with the reproductive choices of humans?
The decline in human birth rates with increased energy consumption is quantitatively identical to the decline in fertility rate with increased metabolism in other mammals. Put another way, North Americans consume energy at a rate sufficient to sustain a 30,000-kilogram primate, and have offspring at the very slow rate predicted for a beast of this size . . . As infrastructure grows we get more out of it, but must invest more into it, reducing the energy and capital left to invest in the next generation.
Moses disagrees with alternative explanations, such as availability of birth control or decisions to marry later, because these don’t explain decisions to have fewer children in the first place. She also dismisses the idea that “as societies become wealthier, greater educational investments are made in each child to make them competitive in labour markets” because investments in eduction correlate inversely with fertility rates.
Sometimes, when I see videos of President Barack Obama, I think of how important it might be for Americans to see photos and videos of highly-accomplished African-American role models. For decades, television has too often portrayed African-Americans as dysfunctional, lazy or violent criminals. The onslaught of these abnormal images has been terrible and relentless. I assume that these media caricatures have damaged and even destroyed some lives by encouraging young African-Americans to think that they are worth less because their physical appearance is different than those TV characters who are more often portrayed to be capable or admirable.
There was a time in my life when I didn’t believe that media images could be so powerful. It’s not that my attitude completely changed on one particular day, but I do recall one especially memorable day. In 2001, my wife (Anne) and I traveled to China to adopt our second daughter (our first daughter is also Chinese). While we were staying in a hotel in Changsha, Hunan Province, I decided to carry my new 9-month old daughter to a nearby department store to get some baby supplies. At that department store, I was surprised to see so many Caucasian mannequins. I took a photo of one of these displays. Back at the hotel, I asked two English-speaking Chinese tour guides why there were so many Caucasian mannequins, rather than Chinese mannequins. They both told me, without hesitation, that Chinese women think that Anglo women are more beautiful. I was incredulous when I heard this. But after it sunk in, it became a sad idea, indeed. I had just adopted my second daughter from China. She was a startlingly beautiful little baby. Back in Changsha, hoped that it would never occur to my daughter that she was not “pretty” because she was not Anglo.
Those who are truly interested in community-building (rather than striving to enhance their own status through resource-exhausting displays of material wealth) might want to take note of two ways city folks play in water. This idea occurred to me while walking through Tower Grove Park in St. Louis last week. Dozens of children splashed in […]
Who is best prepared to deal with a severe economic depression? Based on the work of educator and author Ruby Payne, the best survivors in difficult economic times might be those who are in the lowest economic class, those in “generational poverty.” Payne has spent her career studying the mindsets of economic classes and studying […]
I am a wealthy person, but not in the way most people understand “wealthy.” I don’t drive an expensive car (I drive a 9-year old Saturn). I don’t own a vacation house. I don’t expect to retire for many years. I am wealthy because I am a survivor. I have repeatedly escaped adversity and I’ve […]
This question is not really fair. After all, there are many people out in the suburbs who don’t have it easy and there are many people living in the city who have never had to overcome serious challenges. Nonetheless, it is my prejudice that those people with the highest character, those people we admire the […]
This set of charts is shocking. It’s part of a website entitled “Too Much.” Here’s an excerpt from the “About” page: Each and every week, Too Much explores excess and inequality, in the United States and throughout the world. We cover a wide swatch of economic and political territory, everything from executive pay and […]