Monday, June 28, 2010

Trust and Testosterone

The latest issue of PNAS has this study which suggests that testosterone decreases trust in socially naïve humans. Here is the abstract:

Trust plays an important role in the formation and maintenance of human social relationships. But trusting others is associated with a cost, given the prevalence of cheaters and deceivers in human society. Recent research has shown that the peptide hormone oxytocin increases trust in humans. However, oxytocin also makes individuals susceptible to betrayal, because under influence of oxytocin, subjects perseverate in giving trust to others they know are untrustworthy. Testosterone, a steroid hormone associated with competition and dominance, is often viewed as an inhibitor of sociality, and may have antagonistic properties with oxytocin. The following experiment tests this possibility in a placebo-controlled, within-subjects design involving the administration of testosterone to 24 female subjects. We show that compared with the placebo, testosterone significantly decreases interpersonal trust, and, as further analyses established, this effect is determined by those who give trust easily. We suggest that testosterone adaptively increases social vigilance in these trusting individuals to better prepare them for competition over status and valued resources. In conclusion, our data provide unique insights into the hormonal regulation of human sociality by showing that testosterone downregulates interpersonal trust in an adaptive manner.

And BBC News has the scoop on the study here. A sample:

Testosterone reduced interpersonal trust, say the researchers, "but only in subjects who were generally trusting, and therefore more at risk for deceit".

Whereas in some mammals, testosterone is confined to motivating aggression in competition for status and resources, "in humans the hormone seems to motivate for rational decision-making, social scrutiny, and cleverness, the apparent tools for success in a modern society," Jack van Honk and colleagues explain.

Dr Daryl O'Connor, a health psychologist from the University of Leeds, says these findings are broadly consistent with previous research which showed that testosterone injections in men influenced aspects of their spatial and verbal abilities.

He said: "There is growing evidence to suggest that testosterone has activational as well as organisational effects in men and women.

"It is possible that testosterone can activate changes in the way we perceive and think about aspects of the world," he said.

"However, it is important to remember that hormones never act in isolation and do not account for behaviour on their own."


Tuesday, June 22, 2010

Where the Action Is: On the Site of the Playful Life (Part 7: In Pursuit of the Play Dividend)

This post in the latest installment in my series of posts on the importance of play

This morning I read this short article by Bertrand Russell entitled "In Praise of Idleness". As always, Russell is the perfect author to turn to for inspiration on bold and imaginative ideas.

So Russell's article has inspired me to write a post that brings together a number of themes I have been working on of late- namely, health, happiness and play. And that proposal is that the government ought to prioritize and implement what we might call the pursuit of the "Play Dividend".

What do I propose? We need to increase the opportunities for play at all stages of the human lifespan. The Play Dividend focuses on a two-fold strategy:

(1) reconceptualising the education of our children, so that play is an intricate part of their physical, social, imaginative and moral development; and

(2) to re-calibrate the balance between work and play in adulthood by reducing the number of hours (by an average of 2 hours a day) spent in paid employment. Instead of the standard full time workload of 8 hours a day, 5 days a week, the Play Dividend campaign would transform this to 6 hours a day, 5 days a week (or, alternatively, 7.5 hours for 4 days).

Such a proposal is, I believe, a modest yet feasible one that would help the population and governments more accurately appreciate and value the importance of the opportunities for leisure, family and play.

What would the benefits of the Play Dividend most likely be? I think there are at least 5 important identifiable benefits:

(1) A happier population
(2) A healthier population
(3) Healthier families
(4) More creative individuals and cultures
(5) 1-4 would bring enormous economic benefits.

Pursuing the Play Dividend ought to become a priority for all countries affluent enough to pursue and implement it. Yet, sadly, it is unlikely to get strong support (at least initially) from the very people who would benefit the most from it- the citizenry themselves. Why is there likely to be so much opposition to this proposal? No doubt there are many factors at play. I will briefly identify only a few.

One concern is simply economical- many people will be unwilling to give up the income they would lose by reducing the number of hours they work. They (falsely) believe that more money will bring them greater happiness, and the prevalence of this belief is thus a major obstacle to realizing the Play Dividend.

Advocates of the Play Dividend need to topple the myths upon which current economic policies are premised. Rather than simply assuming that growing a nation's GDP is the most important goal, we need a rival of the Aristotelian vision of politics as the science primarily concerned with eudaimonia (happiness). Advocates of the Play Dividend thus need to draw upon insights from philosophy and the findings of positive psychology in order to effectively pitch the proposal.

Another reason that many will object to the Play Dividend is identified by Russell in "In Praise of Idleness". Namely, that we are raised to believe that "work for work's sake" is a virtue and that play and leisure a vice. And this is why it is vital to instill a respect for the importance of play early in a child's education. If our children are raised to respect play and leisure they will treasure them throughout their whole life. Thus the Play Dividend can serve as the basis for an ambitious reform in education at all levels of schooling.

By the time a child finishes high school they should have developed at least one physical sport (e.g. sport like soccer, or running, or weight training, etc.) and one artistic endeavour (e.g. mastering a musical instrument, drama, culinary art, dance, etc.) to a level of enjoyment and achievement that they will stay with them for the rest of their lives. These activities would, in effect, be an intricate part of their identity. And teachers and the education curriculum should be as determined to ensure that all children finish school with these two skills as they are concerned that all students develop the skills necessary to enter the workforce (e.g. read, write, math, science, etc.).

Envision your 13 year-old child coming home from school and saying "I learned how to cook chicken Parmesan today". Or imagine a homework assignment that entails helping to teach your child how to cook the family an omelet breakfast on Sunday or help plan the next family vacation.

The pursuit and celebration of leisure and social and imaginative play ought to be integral part of our development, from childhood through retirement.

Sadly, time for family and play is becoming more and more scarce. This report notes that, over the past 20 years, the amount of time women spend with their families has declined by 39 minutes for the typical working day and for men the decline was 45 minutes. The reduced working hours of the Play Dividend campaign would help parents and spouses re-claim that valuable time back. What could be more important than having more time to spend with loved ones? You can't put a monetary value on this time and yet our culture has become so impoverished that we have let the most important opportunities to our health and happiness erode. Namely, our relationships with loved ones. Help reverse this sad state of affairs. Demand your government support the Play (or call it the "Family" or "Leisure" or "Creativity") Dividend.

Here are some inspirational Ted talks that endorse the values and principles which underpin the Play Dividend campaign:


Tuesday, June 15, 2010

Mating Competition and Mortality Rates

If you head over to this web page you can find the chart posted above which illustrates the difference in health and life expectancy for men and women in Canada.

Why is it that men have higher mortality rates than women?

This article in the latest issue of Evolutionary Psychology suggests that the answer is- mating competition.

The press release for the paper explains: "women invest more physiologically in reproduction than men, thus men compete with other men for mating partners and try to make themselves attractive to women. This competition leads to strategies that are riskier for men both behaviorally and physiologically, and these result in higher levels of mortality".

Here is the abstract:

Sex differences in mortality rates stem from a complex set of genetic, physiological, psychological, and social causes whose influences and interconnections are best understood in an integrative evolutionary life history framework. Although there are multiple levels of mechanisms contributing to sex based disparities in mortality rates, the intensity of male mating competition in a population may have a crucial role in shaping the level of excess male mortality. The degree of variation and skew in male reproductive success may shape the intensity of male mating competition, leading to riskier behavioral and physiological strategies. This study examines three socio-demographic factors related to variation in human male reproductive success; polygyny, economic inequality, and the population ratio of reproductively viable men to women across nations with available data. The degrees of economic inequality and polygyny explained unique portions in the sex difference in mortality rates, these predictors accounted for 53% of the variance. The population ratio of reproductively viable men to women did not explain any additional variance. These results demonstrate the association between social conditions and health outcomes in modern nations, as well as the power of an evolutionary life history framework for understanding important social issues.

And this comment from the conclusion is worth noting, and is important for political philosophers:

.... despite the potential benefits of economic leveling interventions, any effort to substantially reduce variations in wealth and resource control will likely face considerable political opposition. Paradoxically, opposition to such redistributions will be especially prevalent from men. Due to the long association of male status and reproductive success in our evolutionary history, men are both more sensitive to their position in the social hierarchy as well as to perceived threats to their relative status. The fragility of socialist utopias such as the Paris Commune of 1871 and other communities intentionally suppressing status differentials reveals the difficulty in sustainably implementing such social structures. Edward O. Wilson once remarked that “Karl Marx was right, socialism works; it is just that he had the wrong species” (Novacek, 2001). In sum, this study contributes to the growing body of literature demonstrating the substantial benefits that the evolutionary framework offers for understanding social patterns and important social issues.

This last point provides perhaps an interesting response to Cohen's question "If You're An Egalitarian, How Come You Are So Rich"? Answer: because our interest in sex outweighs our interest in an egalitarian ethos.

I'm not saying this is a morally justified response. But it further illustrates how important it is for political philosophers to take human nature seriously. The factors at play in our psychology are much more complex than simple greed. Rather than focusing on just market incentives (which is Cohen's focus), the egalitarian ought to dig deeper and consider the impact mating competition has played (and continues to) on our psychology.


Sunday, June 06, 2010

Annals of the NY Academy of Sciences Publication

My paper "Why Aging Research?" is now published in the latest issue of the Annals of the NY Academy of Sciences. Here is the abstract:

The American philosopher John Rawls describes a fair system of social cooperation as one that is both rational and reasonable. Is it rational and reasonable for societies that (1) are vulnerable to diverse risks of morbidity (e.g., cancer, heart disease) and mortality and (2) are constrained by limited medical resources, to prioritize aging research? In this paper I make the case for answering "yes" on both accounts. Focusing on a plausible example of an applied gerontological intervention (i.e., an antiaging pharmaceutical), I argue that the goal of decelerating the rate of human aging would be a more effective strategy for extending the human health span than the current strategy of just tackling each specific disease of aging. Furthermore, the aspiration to retard human aging is also a reasonable aspiration, for the principle that underlies it (i.e., the duty to prevent harm) is one that no one could reasonably reject.

And a few samples from the article, to help give you a sense of the different issues I address in the paper:

All else being equal, the more simple and self-evident the justification for supporting a cause, the easier it will be to generate support for that cause. Unlike research on treatments for specific diseases, the justification for prioritizing biomedical gerontology is not self-evident and simple. The skeptic will ask: What are the costs of aging? What kinds of benefits could be reaped by an applied gerontological intervention? What is the “aging ideal” that research on the biology of aging strives to help us realize? Unlike advocates of cancer research, advocates of aging research have no simple and obvious answers at hand to these difficult questions. The field of biogerontology does not reap the benefits that justificatory simplicity often provides advocates of research for specific diseases. And this predicament no doubt helps (at least partially) explain why less than 0.1% of the 2006 National Institutes of Health budget of $28 billion was spent on understanding the biology of aging.3

....A person’s interest in remaining healthy and alive does not evaporate as the number of birthday candles they accumulate increases. The aged, like the young, have an interest in remaining healthy and vigorous for as long as possible. When a person over age 65 is murdered or killed in a car accident we conceive of these events as constituting a serious harm. We believe that there is a moral duty to prevent these harms from being realized, if it is possible to do so. Whether these harms come from an external source that we can easily perceive (such as a criminal wielding a gun or a speeding car) or from complex biological processes that are internal to our biology is irrelevant to the stringency of the moral duty to prevent harm.

....A realistic time frame for realizing the benefits of any health innovation must take seriously the diverse logistics involved in making these benefits accessible to diverse populations. The tasks of monitoring water quality and pollution are complex and large-scale endeavors. Governments face many coordination challenges, such as enforcing compliance, for both rural and densely populated urban settings. And so the general affluence of a country, as well as its natural resources, profoundly influences the quality of sanitation it can offer its citizens. But in the case of developing an antiaging pill to protect against chronic disease, there is good reason to believe that many of these obstacles will be less of a challenge.

Unlike sanitation, the main costs associated with the development of an antiaging pill will most likely be with research and development, rather than the manufacture and dispersion of such a pill. So I believe there is good reason to be optimistic that such an antiaging intervention could be enjoyed by most of the world’s population in a relatively short time from when it is first developed. Especially if we make, as we ought to, the commitment to retard human aging a global, and not just a domestic, health priority.


Thursday, June 03, 2010

Genetics of Infectious Disease

The role our genes play in increasing or decreasing our susceptibility to various diseases has become an area of intense study in the biomedical sciences. News stories often report about studies that find that a particular gene increases the risk of various chronic diseases, like cancer and Alzheimer's disease.

But our genes also influence our risk of infectious disease. In this earlier post I noted this study which identified a group of genes that helped make the 1918 flu so deadly. And in this previous post I linked to a recent study that found a family of genes that influence the ability of HIV to cause infection.

The latest issue of the New England Journal of Medicine has this study which examines the risk CISH alleles have for the development of infectious disease. Here is the abstract:

Background The interleukin-2–mediated immune response is critical for host defense against infectious pathogens. Cytokine-inducible SRC homology 2 (SH2) domain protein (CISH), a suppressor of cytokine signaling, controls interleukin-2 signaling.

Methods Using a case–control design, we tested for an association between CISH polymorphisms and susceptibility to major infectious diseases (bacteremia, tuberculosis, and severe malaria) in blood samples from 8402 persons in Gambia, Hong Kong, Kenya, Malawi, and Vietnam. We had previously tested 20 other immune-related genes in one or more of these sample collections.

Results We observed associations between variant alleles of multiple CISH polymorphisms and increased susceptibility to each infectious disease in each of the study populations. When all five single-nucleotide polymorphisms (SNPs) (at positions –639, –292, –163, +1320, and +3415 [all relative to CISH]) within the CISH-associated locus were considered together in a multiple-SNP score, we found an association between CISH genetic variants and susceptibility to bacteremia, malaria, and tuberculosis (P=3.8x10–11 for all comparisons), with –292 accounting for most of the association signal (P=4.58x10–7). Peripheral-blood mononuclear cells obtained from adult subjects carrying the –292 variant, as compared with wild-type cells, showed a muted response to the stimulation of interleukin-2 production — that is, 25 to 40% less CISH expression.

Conclusions Variants of CISH are associated with susceptibility to diseases caused by diverse infectious pathogens, suggesting that negative regulators of cytokine signaling have a role in immunity against various infectious diseases. The overall risk of one of these infectious diseases was increased by at least 18% among persons carrying the variant CISH alleles.