Demography

Declining Life Expectancy in the Richest Country in the World

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A new paper (discussed in this New York Times article) shows what many demographers have suspected for a while.  Life expectancy in the nation's poorest counties has actually declined since 1983, while life expectancy continues to rise for the more affluent counties.  This finding stands in stark contrast with the trends recorded from 1961-1983.  During this period, life expectancy increased in nearly every county in the United States.  The basic idea is that if you were well off when Ronald Reagan entered the White House, you have done well in terms of mortality since.  However, if you had the misfortune of being poor, then you have typically fared less well.  The result? Diverging health fortunes among the haves and the have-nots in American society.  

This finding relates to what my colleagues Shripad Tuljapurkar and Ryan Edwards refer to as "the ultimate inequality."  The manifestation of inequality does not get much more stark than through systematic differences in the number of years lived by people of different socioeconomic or ethnic backgrounds.   

In the 1983-1999 period, mortality from the largest cause of death, cardiovascular disease, declined in both rich and poor counties.  So what has caused the divergence in life expectancy between rich and poor counties?  It appears to be driven largely by increased mortality among the poor from diabetes and other non-communicable diseases on the one hand, and lung cancer and chronic obstructive pulmonary disease (COPD; of which emphysema is an example) on the other.   Among men in the poor counties, the probabilities of death from homicide or HIV/AIDS have also increased.  While the probabilities of death due to either homicide or AIDS increased only a little, homicide and AIDS can have a big impact on life expectancy for a population.   This is because victims of homicide and AIDS are usually young, so that every homicide or AIDS death leads to a relatively large number of lost years for the sub-population. So much for that goal of  "accelerat[ing] CDC’s health impact in the U.S population and to eliminate health disparities for vulnerable populations as defined by race/ethnicity, socio-economic status, geography, gender, age, disability status, risk status related to sex and gender, and among other populations identified to be at-risk for health disparities."  We can do better...

Human Ecology, Infectious Disease

West Nile Virus Activity, Spring 2008

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I don't want to jump to conclusions about global warming, but the extremely early start to the 2008 West Nile Virus season in the Western United States is extremely troubling. Earlier this week, a Maricopa County, Arizona man became the first human case of WNV this year.  The report of a WNV infected bird this week in Bakersfield, California means that WNV has appeared 2 months earlier than last year in Kern County, a place that saw 140 human cases and 4 deaths last year.  There are a number of possible ecological explanations for why WNV activity could be off to such an early start this year.  One set of possibilities  involve warming temperatures. There is real concern that global warming will expand the range of a variety of vector-borne diseases.  Let's hope that dengue and malaria don't manage to invade California too.

Diet & Nutrition, Human Ecology, Infectious Disease

High Rice Prices Affect Nearly Three Billion

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Nearly half the world's population relies on rice as its primary food staple.  In the last three months, the trading price of rice on international markets has nearly doubled.  This is bad news for poor people in Asia and, especially, parts of urban West Africa. One contributor to this dramatic increase in price is the reduced growth in production in places like Vietnam because of viral infections such as grassy stunt virus and tungro and other crop infestations such as brown planthopper.  So far, the infestations have not spilled over into China, the worlds largest rice producer, but one worries about the proximity and borders that are notoriously permeable to the smuggling of agricultural products. 

Evolution, Statistics

Do These Points Form a Curve?

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I was interested to browse through a paper by Buunk et al. in the most recent issue of Evolution and Human Behavior in which the authors report the results of psychological experiments exploring the differential relationship between height and sexual jealousy in women and men. The authors predicted that (self-reported) sexual jealousy would decline with increasing height in men and that women of average height would report the lowest levels of sexual jealousy. The theory driving these predictions is that higher-status, more attractive individuals should be less jealous on average because they are better able to prevail over would-be competitors and, presumably, if they experience partner infidelity, they can always find another partner. The authors cite the abundant evidence for increased social dominance in taller men and suggest the relationship between women's attractiveness and height is quadratic, with women of average height being most attractive. One hundred women and 100 men were asked question, “In general, how jealous are you in your current relationship?” Responses fell on a six point scale ranging from (1) "not jealous" to (6) "morbidly jealous". The authors' results apparently support their hypotheses. So here are the two figures that they use to show that (1) jealously declines linearly with height in men and (2) is quadratic for women, with average-height women least jealous. The first figure is for men:

Buunk et al. (2008) Figure 1

The second figure is for women:

Buunk et al. (2008) Figure 2

Hmmm. I don't know if I would rest much on the interpretation of that figure as being "quadratic." It seems entirely possible that the curve is driven simply by the sparseness of the tails. There are fewer women of extreme height, either tall or short and this allows a few influential points to leverage the line up at the ends. Think about the upper 95% confidence interval of a linear regression line. Doesn't look that different from their figure 2, no? This makes me wonder how robust the relationship is. For example, if we were to bootstrap replicate samples (with replacement) and re-fit the quadratic form, how many would have a significant at some conventional level (e.g., p<0.05)? There is also the question of whether this quadratic curve fits better than a linear relationship. One could test the two nested models using a likelihood ratio test.

Then there is the question of confounding variables. At the very least, it seems that one would want to control for age of the actors, duration of relationship, and quite possibly other measures of wealth or status. It seems reasonable to posit that being extremely wealthy would modify the degree of sexual jealousy experienced by a man of average height, for instance.

This is why I remain a skeptic of evolutionary psychology...

Reference

Buunk, A.P. J. H. Park, R. Zurriaga, L. Klavina and K. Massar (2008) Height predicts jealousy differently for men and women. Evolution and Human Behavior. 29(2):133-139.

Human Ecology

On Culture and Ecological Anthropology

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Following up on a thread still circulating on the EANTH List, the question arose of how essential is the concept of culture for defining ecological anthropology. In an earlier post, I had objected to the idea that culture lies at the center of ecological anthropology. For instance, most scholars coming out of an ethological tradition (e.g., primatologists, human behavioral ecologists) see behavior as the focus of their analysis. Especially important for primatologists are relationships, which scale to yield social structure, an idea quite distinct from culture. In the continuing debate on EANTH-L, a suggestion was made that while culture may not be important for primatologists, primatologists are an abject minority of ecological anthropologists and therefore are not really relevant for defining the field. Without "culture" in the definition, ecological anthropology loses its heart. No mention was made of human behavioral ecology (HBE). Here, I post an edited version of my latest contribution to this debate in which I specifically address the role of HBE in ecological anthropology.

It is not just the primatologists among us anthropologists for whom culture is secondary. Surely, most anthropologists (at least in the United States) are primarily interested in culture. But defining a field based on the majority practice is rather hegemonic, no? Human behavioral ecologists, a group of scholars mentioned in the big-tent description of ecological anthropology also focus their analysis on behavior, and specifically decision-making. Culture may play a role in such decision-making processes, but it need not. Some HBE contributers to major questions of interest to ecological anthropologists, broadly construed, include: Mike Alvard on hunting and indigenous resource conservation, Smith and Wishnie on the relationships between conservation and subsistence, Rebecca Bliege Bird and Doug Bird on Aboriginal burning, successional dynamics and subsistence, Bram Tucker on subjective discounting, etc. I list some references following this text of work by human behavioral ecologists who are certainly not on the margins of what I would call ecological anthropology. None of these works rely on the analytic concept of culture as a primary explanation.

Those of us trained in the British Social Anthropology tradition may also be able to relate to a certain ambivalence toward the concept of culture. Though a primatologist by training, I find myself as much influenced by the Manchester School of Social Anthropology (e.g., Max Gluckman, John Barnes, Elizabeth Bott) as I am by Robert Hinde. Both primatologists (with their ethological background) and social anthropologists of the British School focus their analysis on social structure that arises through relationships and other social interactions. It was, after all, the Manchester school that gave rise to the field that came to be known as social network analysis, despite the fact that this field is generally associated with sociology today.

So, yes, by all means let's pitch a big tent for what we call ecological anthropology, but let's also cast our definitions of what counts as ecological anthropology in such as way as to be truly inclusive of the various historical traditions within anthropology. Recasting the suggested definition of ecological anthropology somewhat to account for this broader definition, I propose something like:

Ecological anthropology takes as its field of study the role of culture, social structure, and human agency in explaining the dynamic interactions between human populations and the ecosystems in which they are embedded.

This is a rough first approximation. I would like to work in Andrewartha and Birch's definition of ecology as being the distribution and abundance of species in there as well, but that's for another day...

Selected References.

Alvard, M. S. 1998. Evolutionary ecology and resource conservation. Evolutionary Anthropology 7 (2):62-74.

Bird, D.W., R. Bliege Bird, and C.H. Parker. 2005. Aboriginal burning regimes and hunting strategies in Australia’s Western Desert. Human Ecology 33: 443-464.

Bliege Bird, R. (2007) Fishing and the sexual division of labor among the Meriam. American Anthropologist 109:442-451.

Borgerhoff Mulder, M., Caro, T and A. O. Msago. 2007. Integrating anthropological, archeological, biological and historical research in a long term conservation study in the Katavi ecosytem. Conservation Biology 21(3): 647-658.

Gurven, M.D., K. Hill, H. Kaplan, A. Hurtado, R. Lyles. 2000. Food transfers among Hiwi foragers of Venezuela: tests of reciprocity. Human Ecology 28(2):171-218.

Hinde, R. A. 1991. A Biologist Looks at Anthropology. Man (n.s.) 26 (4):583-608.

Ruttan, L. M. and M. Borgerhoff Mulder. 1999. Are East African pastoralists truly conservationists? Current Anthropology 40(5):621-652.

Smith, E. A., and M. Wishnie. 2000. Conservation and subsistence in small-scale societies. Annual Review of Anthropology 29:493-524.

Tucker, B. 2006. A future discounting explanation for the persistence of a mixed foraging-horticulture strategy among the Mikea of Madagascar. In Behavioral Ecology and the Transition to Agriculture, edited by D. J. Kennett and B. Winterhalder. Berkeley: University of California Press.
Pp. 22-40.

Tucker, B. and L. Rende Taylor 2007. The human behavioral ecology of contemporary world issues: Applications to Public Policy and International Development. Human Nature 18(3): 181-189.

Winterhalder, B., and F. Lu. 1997. A forager-resource population ecology model and implications for indigenous conservation. Conservation Biology 11(6): 1354-1364.

Conservation, Demography, Diet & Nutrition, Evolution, Human Ecology

The Requirements for an Ecological Anthropology Curriculum

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A question was posted today on the ecological anthropology listserv: What are the basic requirements for an ecological anthropology graduate program? I don't claim to be qualified to say what these are for the field as a whole, but I am qualified to say what we have decided on in setting up our new ecological and environmental anthropology Ph.D. program at Stanford. Here I include an edited version of the reply I sent to the thread.

At the risk of essentializing, there are, broadly speaking, two general classes of ecological anthropologists: (1) those who use human relationships with the environment as a lens through which to study problems in cultural anthropology (e.g., agency, social structure, the construction of meaning, etc.), and (2) ecologists who study humans as their primary organism. The majority of practitioners currently falling under the latter category are probably human behavioral ecologists, though I can think of some notable exceptions to this. This is the approach our program emphasizes.

In addition to departmental requirements, EE students are required to take the following:

  • Evolutionary Theory
  • Research Methods in Ecological Anthropology
  • Data Analysis in the Anthropological Sciences

All students need to know how to integrate theory, method, and application, but the specific nature of the courses in which they learn that doesn't matter that much. Therefore, we require three courses from a list of theory-driven graduate classes, including (but not limited to):

  • Advanced Ecological Anthropology
  • Human Behavioral Ecology
  • Conservation and Evolutionary Ecology
  • Demography and Life History Theory
  • Environmental Change and Emerging Infectious Disease

Required classes deal with what you know, but equally important is how you know. We expect our students to engage in research from the outset of their graduate studies. Students attend weekly lab meetings. These can be within the Anthropology department (e.g., Rebecca Bird and I run a joint meeting or we have a joint spatial interest meeting this quarter) or in other departments (e.g., Biology, Woods Institute).  Students also attend a colloquium (comprised of visiting speakers) one quarter out of the year.

We're big on methods, but we don't legislate what methods students learn (other than research design and statistics).  Most students are interested in remote sensing and GIS, but we also have students working on social network analysis, demographic methods,  and advanced statistical methodology.

So, that's our idea for a graduate program.  We will have  a proper web page describing the program in detail some time in the future.

notes on human ecology, population, and infectious disease