On the Spirit Level

Behavioural Psychology and The Spirit Level

 

 

Peter Winsley

 

Health inequalities are associated with income inequality and rank status in social hierarchies are at the heart of this.  Rank status inequality is translated into poor health outcomes by biochemical, epigenetic and behavioural mechanisms and these are mediated or triggered by psychological responses to the social environment. 

Developed countries that reduce income and especially rank status inequality are likely to achieve better social outcomes.  Inequality can be reduced by low market income differentials, progressive taxation and income transfers, or policies that promote higher social mobility.  Further improvements in social outcomes will come from better understanding of early human development and epigenetic factors and recognition that individuals differ in their response to the social environment and capacity for self-control. 

 

Keywords: rank status inequality, income inequality, behavioural psychology.

 

Introduction

Studies (e.g. Rodgers 1979, Marmot 1991, Wilson & Daly 1997, Brunner & Wilkinson 1999, Subramanian & Kawachi 2004, Wilkinson & Pickett 2006) have highlighted correlations between high income inequality and poor health.  These have been drawn together in the popular text The Spirit Level (Wilkinson & Pickett 2009). 

Countries with high income inequality tend to higher violence levels (Hsieh & Pugh 1993; Gilligan 1996; Wilson & Daly 1997) and lower trust.  High income inequality is also associated with high fertility and associated social problems such as teenage pregnancy (Gold et al 2004).  Developed countries with the highest income inequality (the US, UK, New Zealand and Portugal) have much higher teenage birth rates (relative to older women’s birth rates) than more equal countries such as Japan, Sweden, Norway and Finland (Wilkinson & Pickett 2009). 

However, before the above correlations can form a basis for policy-relevant inferences, we need to gain a richer picture of the relationships between variables and understand causation.  This paper addresses these questions, and contends that behavioural psychology is key to understanding phenomena discussed in The Spirit Level and related studies.

 

Understanding the correlations

 

Wilkinson & Pickett (2006) reported evidence that, above a certain threshold where societies and individuals can afford good nutrition, sanitation and medical services, what matters for health and other social outcomes is income inequality, that is, relative not absolute income.  This raises questions such as, are health inequalities the result of factors such as health system performance, education and ethnicity rather than income inequality?  If not, are they caused by income inequality directly or by factors associated with it?  Is income inequality simply a proxy for something deeper?

Correlations between income inequality and poor health seem independent of health system differences, being regularities in e.g. Austria that provides universal health care and in the more market-based US system.  Educational inequalities are associated with income inequality (Case et al 2005, Almond 2006, Cutler et al 2008).  Ethnicity is also associated with both income and health inequalities (Mellor & Milyo 2001, Deaton & Lubotksy 2003, Elo et al 2004, Cutler et al 2008).   These however are correlations only and we need to look more deeply to understand causes.  This requires understanding of behavioural psychology and its evolutionary roots:

Evolutionary origins of behavioural psychology

 

Natural selection’s “invisible hand” produced the human mind’s structure and therefore generates the “invisible hand” of economics (Cosmides & Tooby 1994). 

Human psychology evolved in evolutionary time to solve problems our ancestors faced in small social bands where resources were scarce, people both competed and cooperated, survival depended on immediate rather than deferred consumption.  and capital could not be stored or leveraged. Our psychology evolved with face to face exchange not with abstract and impersonal markets, and with direct observation rather than abstract reasoning.  The ability to attract a mate when resources were scarce was dependent on status relative to competitors.  Reference points, such as how one ranks in a status hierarchy, are therefore fundamental

Evolution has shaped such modern psychological phenomena as:

Innate sense of fairness

 

Experimentally and in real world observations people have an innate sense of fairness (Rabin, 1993).  An innate aversion to unfairness is demonstrated in three standard economic experiments: the dictator, ultimatum and trust games.  Imposing losses on others is seen as unfair under conditions where failing to share gains is acceptable.

Willingness to contribute to socially valuable goods can be evolutionarily stable so long as there are mechanisms to discourage free riding (Price et al 2002).  People are hard-wired with cognitive programmes to detect and punish cheaters.  People punish strangers who mistreat other strangers.  Many people will forgo a large sum to deny a larger sum to an anonymous stranger who has treated them badly (Cameron 1999). 

Wilkinson (2000) contends that inequality affects health by insulting humans’ innate sense of fairness.  This is supported in Deaton (2003 p. 115) which notes that “raw correlations that exist [between income inequality and poor health]…are most likely the result of factors other than income inequality, some of which are intimately linked to broader notions of inequality or unfairness.”

Innate need for personal dignity

Robert Fuller (2006) relates individual dignity to “status competition” arguments.  (Wilkinson & Pickett 2009 p. 36) highlight the importance of self esteem, pride and dignity to good health, and Donnellan et al (2005) link low self esteem to conflict.  “Self esteem” can have negative as well as positive aspects.  Positive forms are based on self awareness, and well-founded confidence in one’s abilities.  However, negative forms of “self esteem” involve denial of weakness, a “talking up of oneself”, a self-centred focus on image, insensitivity to others, and narcissism.  This can be associated with status anxiety and hypersensitivity to rank status threat from those of similar social standing.

The importance of dignity and rank status is illustrated across many countries and time periods.  The decline in male life expectancy in Russia following the break up of the Soviet Union and the establishment of a market economy had much to do with the destruction of male self-esteem tied up in jobs that disappeared (Marmot 2004). 

 

Rank status

Dignity and pride are created by how others treat an individual and how an individual is valued and ranked within a hierarchy.  Causative relationships between rank status in a social hierarchy and social outcomes are detailed in e.g. Berkman & Kawachi (2000), Fuller (2006), Offer (2006), Price et al (2007), Wilkinson & Pickett (2009).  The evidence is that health inequalities result from perceived rank status inequality that is associated with but distinct from income inequality (Cutler et al 2008).  As Offer (2006 p. 286) observes “social ranking is a matter of life or death”.  

Some of the earliest empirical evidence comes from Whitehall 1, a long term study of civil servants set up in 1967 (see Marmot 1978; Marmot et al 1991).  This found a strong inverse correlation between position in the civil service hierarchy and death rates.  This and subsequent Whitehall studies found people with low status had higher rates of heart disease, and of some cancers, lung and gastrointestinal diseases.  Those in lower status grades were more likely to smoke, have high blood pressure, be obese and be less physically active, however these lifestyle factors explained only about one third of the differences in heart disease (Wilkinson & Pickett 2009 p 75).

Conversely, there is evidence high status people typically live longer.  Oscar winners live an average four years more than other actors (Fuller 2006 p 96).  Status is associated with self esteem and meaningful life.  Longevity can be enhanced by a high sense of existential purpose and life meaning (Frankl 1959; 1967).  Winston Churchill, a heavy drinking smoker with a poor diet contended he felt little stress during World War Two as he would wake up in the morning with one life purpose: the destruction of Adolf Hitler.

Status competition between individuals can generate net economic loss as well as erode health.  Literature on the relationship between psychology, “over-consumption” and associated phenomena such as “status races” (“keeping up with the Jones”) dates at least from Veblen (1899) and includes Offer (2006).  Frank (1985) contends that increases in wealth and associated consumption do not increase wellbeing but rather change where people sit in an unnecessary hierarchy.  A deeper evolutionary perspective on consumption can be found in Saad (2007).  Status races are wasteful because resources are spent on positional goods, not on those that confer utility, and because these races cannot ultimately be won (“there is no finishing line”).  Advertising pitches exacerbate status competition, inequality ramps up pressure to consume and this causes indebtedness (Wilkinson & Pickett 2009, p 233).

Rank status competition also causes violence.  People are hard-wired to regulate competitive risks in response to social status cues.  Many male-male conflicts with escalating violence begin as disputes over “respect” where a status challenge from a near equal cannot be ignored (Ermer et al 2008).  Such status-driven violence is diminished by reduced rank status inequality and by social cohesion.  Paradoxically, suicide rates can be higher in societies with low rank status inequality, lower violence and higher social cohesion.  Suicide may signify social alienation and may involves people turning their violence on themselves rather than others.

Rank status perception has a subjective element that differs among individuals.  Subjective social status measures are better predictors of composite scores of physical and mental health than occupational grade (Singh-Manoux et al 2005).  Josephs et al (2006) note that some people desire high status while others avoid it. 

Some jobs such as teaching and nursing are of high status though modestly paid, while some high paid jobs can be of low status.  Many people have high status in community organizations (recreational clubs, churches, voluntary organizations) while working in low status jobs. 

Status in a hierarchy may also be associated with group identity.  Some group-related identities may be vulnerable to racist or other stigmatizing behaviour by other groups and this can be a factor in, for example, ethnicity-based health inequalities.  

perception.  Inzlicht et al (2008) report that individuals belonging to stigmatized groups are less able to regulate their own behaviour when they become conscious of their stigmatized status or enter threatening environments.  Coping with stigma can weaken the ability to control and regulate one’s behaviour in domains unrelated to the stigma.  However, people have multiple identities, can shift between them and therefore have some affiliative choice (Sen 2006).  It is often difficult to identify which of an individual’s multiple identities is most relevant to rank status perception. 

 

Understanding the mechanisms

 

If we accept health inequalities are causatively associated with behavioural psychology in general and rank status psychology in particular, we need to dig deeper into the underlying mechanisms.

 

Genetic and epigenetic factors

 

Genes and alleles do not determine anything unless triggered by environmental factors: it is nature via nurture not nature versus nurture.  Gene variants associated with anxiety, extreme risk taking and anti-social behaviours only manifest themselves when triggered by environmental factors such as an abused or stressful childhood or other environmental triggers.  These so-called “bad” gene variants are associated with a heightened sensitivity to all experience and can be a source of creativity and achievement, depending on the social environment’s influence.  This is the basis of the emerging “dandelion-orchid” thesis where some gene variants can be good in some environments and bad in others.  “Dandelion children” do well over a whole rank of environments while “orchid children” will wilt if ignored or abused, but bloom spectacularly with “greenhouse” care.  The “orchid” genes can therefore be seen as highly leveraged evolutionary bets that humanity needs rebels and risk takers as well as stable risk managers.

Epigenetic[1] early stage human development is influential in later stage physical and cognitive development.  People with a poor start in life will be born with physical and cognitive development problems and this will influence later health and social problems.   A developing fetus takes a biochemical “weather forecast” predicting the kind of world it is likely to be born into (Gluckman 2009).  If its mother is psychologically stressed due, for example, to domestic violence the signal is that life is dangerous and possibly short and it is best to economise on brain and other cells needed for a longer more stable life and favour the development of early maturation, physical strength and fast reaction times.

If a fetus is poorly nourished it develops capacity to store fat in anticipation of scarcity; when it is born into a food-rich world the individual in later life may be prone to obesity and associated problems such as diabetes. Obesity also results from social factors such as high consumption of energy-rich and nutrient-poor processed foods, and “time deficits” as parents “cut corners” in food preparation with convenience foods.  This is compounded by the psychology of food advertising.

Parents with stressful lives may have high fertility levels and this and associated psycho-social factors can have intergenerational effects.  When a developing baby “predicts” its life will be short its epigenetic biological switches will favour short term development that maximizes the chance of early life reproduction at the expense of long life and the investments needed to support it. The biological (and the later social) signal for girls who will grow up with poor prospects might be: “life is dangerous and short so reproduce as early as you can.  This means your children are more likely to have a living mother (and perhaps grandmothers) to provide for them to an age where they can become independent.” 

Biochemical mechanisms

 

Low social status is stressful because it reduces people’s control over their lives and because low status people feel looked down upon (Charlesworth et al 2004).  Such stress has biochemical ramifications.  Dickerson & Kemeny (2004) show that exposure to social evaluative threats raises stress hormone (cortisol) levels. Maner et al (2008) report drops in testosterone levels among socially anxious men who lose a competition.

 

A key mechanism is “fight or flight” where threats trigger energy mobilization, blood vessels constrict, clotting factors are released into the blood stream in anticipation of injury, and lungs and heart work harder.  Blood is diverted from essential organs to skeletal muscles and the senses and immune system are enhanced.  Over the short term this is a healthy response; over the long term if stress is ongoing damage starts to occur.  This damage includes higher glucose levels in the bloodstream leading to obesity and perhaps diabetes, and hypertension and heart disease due to blood vessel constriction and raised levels of blood clotting factors (McEwen 1998, Seemen et al 2001, Epel et al 2004, Cawthon et al 2003, Wilkinson & Pickett 2009 p 86).

The above biochemical mechanisms are similar to those found in monkey and baboon experiments – significantly animals with social hierarchies, and our close genetic cousins (Sapolsky 1993, 2004). 

High rank status inequality can erode trust and this has biochemical implications.  The hormone oxytocin is associated with trust and with social attachment and bonding more generally.  There is experimental evidence (Kosfeld et al 2005) showing that oxytocin levels are boosted by increased trust between people.

The above biochemical mechanisms transmit psychological reactions into physiological effects.  The psychological response is the trigger that translates a reaction to social status stress into biochemical mechanisms with subsequent physiological impacts.  The direct p impacts are compounded by indirect effects on behaviour and lifestyle which in turn may have second order physiological impacts.

 

Baumeister et al (2005) report experiments showing that being excluded or rejected causes decrements in self control. 

 

Where people lack self control they may abuse their own health or commit crime or anti-social acts.  It is for this reason that society generates ways of helping people regain self control (religious beliefs, military-style boot camps), or where that self-control is irretrievably lacking to protect the community from the negative effects (prisons).

 

Psycho-social factors

Psycho-social pathways have health implications (Marmot & Wilkinson 2001), and they amplify wider social risks.  For example, in modern times young people develop sexually before they are fully developed cognitively and socially (Gluckman & Hanson 2006).  This disconnect between biological and social maturation is compounded by advertising targeting children and young people, the sexualisation of childhood in advertising and the media, and by popular culture and social norms.

Young people who, when growing up, perceive others as untrustworthy, relationships as opportunistic or self-serving and resources as scarce or unpredictable will reach biological maturity and be more sexually active earlier.  They will be less inclined to long term relationships and invest less in parenting (Belsky et al 1991).

Parents psychologically shape children’s life plans and expectations.  Middle class parents with high aspirations for their children may refer to them in diminishing ways, as “rug rats” or “ankle biters” (something obnoxious underfoot), or  “little possums” (something pestiferous overhead), as if to delay their maturation.  In contrast, lower socio-economic parents who expect their children to become more self reliant at a younger age encourage “stoic and staunch” behaviours, pretending to be more adult at a younger age, with these children being referred to in more adult terms such as “youth” or “bro”.  

People also respond to direct economic incentives.  Poorly educated teenage girls face low opportunity costs of having children compared to the cost of a higher education.  With social welfare support available, having a child may make economic sense, as well as bringing identity, role definition and a socially mandated status. 

 

Policy implications

 

The Spirit Level evidence suggests that income inequality is associated with and in some senses is a proxy for more deep-seated phenomena, notably rank status inequality that has Darwinian evolutionary roots.  Countries minimize income and rank status inequality through different policy routes.  Japan has low wage/salary differentials while Scandinavian countries use progressive tax and income transfers.  Some countries (Canada, and historically the US) have minimized income inequality, at least over generations, through higher social mobility.  New Zealand uses “mana enhancement” initiatives to build Maori pride and dignity, progressive tax and transfer policies, and uses education policy to foster social mobility.

Through an individual’s lifecycle status-related inequalities are transmitted and have health impacts through different mechanisms.  At the fetal stage the transmission mechanism is epigenetic.  The policy response to this must be to ensure children get the best possible start in life, which means mothers must be protected from stress such as domestic conflict, be well nourished, and avoid harmful drugs.  Social policy might well be more “front loaded” in favour of early human development stages, while expecting more personal responsibility and less social policy input at later life stages.

At the early childhood through to youth stages what matters is nurturing, education and peer influence.  The “dandelion-orchid” theory suggests that many at risk children will respond extremely well to “hot house” interventions that turn risk into creative opportunity. 

Other policy options include reducing inequality in market earnings, progressive tax policies, and enhancing social mobility by increased educational investment and reducing professional and industry regulatory barriers.  Such policies need to be reinforced by social norms and prevailing popular culture, are influenced by “authority bias” and by examples (positive or negative) set by high status exemplars.  They are inextricably linked to political and moral philosophy questions relating to individual autonomy and expectations of personal responsibility and self control, versus what the state or civil institutions can be responsible for.

 

Conclusion

Health inequalities and other social “bads” result primarily from rank status rather than income inequality as such.  Reducing rank status inequality is a moral philosophy as well as a socio-economic policy issue and is significantly influenced by psycho-social factors.  Countries can choose different routes to reduce inequality, and this also requires understanding of human development stages and the psychology associated with them.  

References

Almond D (2006): Is the 1918 influenza pandemic over?  Long-term effects of in utero influenza exposure in the post-1940 U.S. population.  Journal of Political Economy 114: 562-712.

Baumeister, R.; DeWall, C. N.; Ciarocco, N.; Twenge, J. 2005: Journal of Personality and Social Psychology 88 (4), 589-604.

Belsky, J.; Steinberg, L.; Draper, P.  (1991): Childhood experience, interpersonal development, and reproductive strategy: an evolutionary theory of socializations.  Child Development 62 (4), 647-70.

Berkman, L; Kawachi, I. (eds) (2000): Social epidemiology.  New York: Oxford University Press.

Brunner E. Marmot M G. (1999): Social organization, stress and health.  17-43 in  Marmot, M.; Wilkinson, R. (eds): Social determinants of Health. Oxford: Oxford University Press. 

Cameron L (1999): Raising the stakes in the ultimatum game.  Experimental evidence from Indonesia.  Economic Inquiry 37 (1), 47-59.

Case, A.  , Fertig, A. Paxson, C. (2005): The lasting impact of childhood health and circumstance.  Journal of Health Economics 24, 365-389.

Case & Paxson (2002): Parental behavior and Child Health.  Health Affairs 21 (2), 164-178.

Cawthon A.; Smith, K.; O’Brien, E.;  Sivatchenko, A.;  Kerber, R. (2003): Association between telomere length in blood and mortality in people aged 60 years or older.  Lancet 361 (1),  393-395.

Charlesworth, S. J.; Gilfillan, P.; Wilkinson, R. (2004): Living inferiority.  British Medical Bulletin 69, 49-60.

Cosmides, L.; Tooby, J. (1994): Better than rational: evolutionary psychology and the invisible hand.  American Economic Review 84 (2) Papers and proceedings, 327-332.

Cutler, D M.; Lleras-Muney, A.; Vogl, T. (2008): Socioeconomic status and health: Dimensions and mechanisms.  NBER Working Paper 14333.

Deaton, A Lubotsky D. (2003): Mortality, inequality and race in American cities and states.  Social science and medicine 56(6), 1139-1153.

 

Dickerson, S. S.; Kemeny, M. E. (2005): Acute stressors and cortisol responses.  Psychological Bulletin 130, 355-391.

 

Donnellan, M.; Trzesniewski, K.; Robins, R.; Moffit, T.; Caspi, A. (2005): Low self-esteem is related to aggression, anti-social behavior and delinquency. Psychological Science 16, 328-335.

Elo, I.T.; Turra, B.  Kestenbaum B; Ferguson B. R. (2004): Mortality among elderly Hispanics in the United States: past evidence and new results. Demography 41, 109-128.

 

Epel E. S.  Blackburn E. H., Lin J et al (2004): Accelerated telomere shortening in response to life stress.  PNAS 101 (49), 17,312 -17, 315.

Ermer E. Cosmides L. Tooby J (2008): Relative status regulates decision making about resources in men: evidence for the co-evolution of motivation and cognition.  Evolution and human behaviour 29, 106-118.

Frank, Robert (1985): Choosing the right pond: human behavior and the quest for status.  New York: Oxford University Press. 

Frankl, V. (1967): Psychotherapy and Existentialism.  New York: Simon and

Schuster. 

Frankl, V. (1959): Man’s search for meaning.  New York: Simon and Schuster.

Fuller, R. 2006: All rise.  Somebodies, nobodies and the politics of dignity.  San Francisco: Berrett-Koehler Publishers.

 

Gilligan, J. (1996): Violence: Our deadly epidemic and its causes.  New York: G.P. Putnam.

 

Glaeser, E. L. (2003).  Psychology and the market.  NBER Working Paper 10203.

 

Gluckman, P. (2009): Growing old before you are born.  Dialogue, Newsletter of the Liggins Institute.

 

Gluckman, P., Hanson, M. (2006): Mismatch.  Oxford University Press.

Gold, R.; Connell, F.; Heagerty, P. et al (2004): Income inequality and pregnancy spacing.  Social Science and Medicine 59, 1117-1126.

Hsieh, C.; Pigh, M. (1993): Poverty, income inequality, and violent crime: a meta-analysis of recent aggregate data studies.  Criminal Justice Review 18,  182-202.

 

Inzlicht, M.; McKAy, L.; Aronson, J. (2008): Stigma as ego depletion.  How being the target of prejudice affects self-control.  Psychological Science 17, (3), 262-269.

 

Josephs, R.; Sellers, J.; Newman, M.; Mehta, P. (2006): The mismatch effect: when testosterone and status are at odds.  Journal of Personality and Social Psychology 90 (6), 999-1013.

Kosfeld, M.; Heinrichs, M; Zak, P; Fischbacher, U.; Fehr, E. (2005): Oxytocin increases trust in humans.  Nature 435, 673-6.

Maner, J. Miller, S., Schmidt, N.; Eckel, L. (2008): Submitting to defeat: Social anxiety, dominance threat and decrements in testosterone.  Psychological Science 19 (8), 764-768.

Marmot M. G.l et al (1991): Health inequalities among British civil servants: The Whitehall 11 study.  Lancet 337 (8754), 1387-1393.

Marmot, M. G. Rose, G. Shipley, M. Hamilton PJS (1978): Employment grade and coronary heart disease in British civil servants.  Journal of Epidemiology and Community Health 1978 32, 24-249.

Marmot, Michael (2004): The status syndrome.  How social status affects our health and longevity.  New York, Times Books.

Marmot, M.; Wilkinson, R. (2001): Psychosocial and material pathways in the relation between income and health.  British Medical Journal 322, 1233-1236.

 

McEwen B. S. (1998): Protective and damaging effects of stress mediators.  New England Journal of Medicine 338 (3): 1771-1779.

Mellor J. M.; Milyo, J. (2002): Income inequality and health status in the United States: Evidence from the Current Population Survey.  Journal of Human Resources 37, (3),  510-539.

Offer, Avner (2006): The challenge of affluence.  Self-control and well-being in the United States and Britain since 1950.  Oxford University Press.

Price, J. S.; Gardner, R.; Wilson, D. R.; Sloman, L.; Rohde, P.; Erickson, M. (2007): Territory, rank and mental health: The history of an idea.  Evolutionary Psychology 5 (3) 531-554.

Price, M.; Cosmides, L.; Tooby, J. (2002): Punitive sentiment as an anti-free rider psychological device.  Evolution and Human Behavior 23, 203-231.

 

Rabin, M.  (1993): Incorporating fairness into game theory and economics.  American Economic Review 83 (5), 1281-1302.

 

Rodgers, G. (1979): Income and inequality as determinants of mortality: an international cross-section analysis.  Population Studies 33 (3), 343-51.

Saad G (2007): The evolutionary bases of consumption.  Mahwah, New Jersey Lawrence Erlbaum Associates.

 

Sapolsky R. M. (1993): Endocrinology alfresco: Psychoendocrine studies of wild baboons.  Recent Progress in Hormone Research 48, 437-468.

 

Sapolsky R. M. (2004): Why Zebras Don’t Get Ulcers.  An updated guide to stress, stress-related diseases, and copying.  (3rd Edition).  New York, Freeman. 

Seeman, T; McEwen, B; Rowe, J; Singer, B. (2001): Allostatic load as a marker of cumulative biological risk: MacArthur studies of successful aging.

Proceedings of the National Academy of Sciences 98 (8), 4770-4775.

Sen A. (2006) Identity and violence.  New York, W W Norton Books.

Singh-Manoux, A. Marmot, M. G. Alder N. E. (2005): Does subjective social status predict health and change in health status better than objective status?  Psychosomatic Medicine 67, 855-861.

Subramanian, S.; Kawichi, I (2004): Income inequality and health: what have we learned so far?  Epidemiologic Reviews, 26, 78-91.

 

Veblen, T. (1899): The theory of the leisure class: an economic study of institutions. 

Wilkinson R. G. (2000): Mind the Gap: Hierarchies, Health and Human Evolution.  London: Weidenfeld and Nicolson.

Wilkinson, R.; Pickett, K. (2009): Spirit Level.  Why more equal societies almost always do better.  London, Allen Lane.

Wilkinson, R.; Pickett, K. (2006): Income inequality and health: a review and explanation of the evidence.  Social Science and Medicine 62 (7), 1768-1784.

Wilson, M.; Daly, M. (1997): Life expectancy, economic inequality, homicide and reproductive timing in Chicago neighborhoods.  British Medical Journal, 314 (1271).

 


[1] Epigenetics is permanent changes in gene expression due to environmental factors, especially at fetal stage development.

Advertisements

About Peter Winsley

I’ve worked in policy and economics-related fields in New Zealand for many years. With qualifications and publications in economics, management and literature, I take a multidisciplinary perspective to how people’s lives can be enhanced. I love nature, literature, music, tramping, boating and my family.
This entry was posted in Papers. Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s