Scientists, philosophers, religious leaders, and ordinary people have argued for ages about how people develop their values: the "moral compass" that is often referred to when a person does something virtuous or abhorrent. The age-old argument is often "nature vs. nurture," the debate about what impacts people's behavioral development more - those innate values that make them "human" or their personal experiences and the way they are raised.
According to recent research conducted by University of New Mexico Biology professor Randy Thornhill and research assistant professor Corey Fincher, nature does indeed impact people's values, but it's the impact of nature on people, as opposed to the nature of people that matters.
"Our theory says that if you're raised in a disease-rich environment you go towards the conservative end of the vales spectrum," Thornhill said. "If, on the other hand, you're raised in a relatively low disease environment then you go towards the liberal end."
Thornhill and Fincher argue that many core pieces of people's values (e.g. prejudice vs. equality) tend to rise ultimately from encounters of human evolutionary ancestors with infectious diseases. And now experiences with infectious diseases shape human values during each individual’s lifetime. Called the "parasite stress theory of values," their premise suggests that in areas with a higher level of infectious diseases (such as tropical countries, and some countries located in Eastern Europe and Asia), ,people have adopted a more conservative ideology from a young age - with an ethnocentric belief that members of the community shouldn't leave and others from outside the community should be looked on suspiciously. Conservative values, Thornhill and Fincher argue, are defenses against infectious diseases.
People living in lower disease parts of the world tend to have more liberal values that promote larger social networks and interactions with new kinds of people and different ideas. The cost of this expanded worldview is greater exposure to potential diseases from that larger social network, and hence liberal values are, on balance, beneficial only when infectious disease stress is low.
Thornhill said, “In recent scientific papers we have shown a robust relationship between infectious disease level and and human values across the world and across the states of the U.S.A. The research shows that as infectious disease stress increases across regions, so too does degree of conservatism.”
Religiosity, Democratic Values Among Areas Measured
Thornhill's research team also examined the expansion, success and failures of democracies. Political scientists measure the level of "democracy" in countries throughout the world - measuring how widespread wealth, opportunities and participation in social affairs, among other things, are throughout the country. According to Thornhill there is a very strong pattern across the world of advanced democracy being associated with low infectious-disease adversity. In turn, democracy and liberal values are strongly intertwined.
Each area's belief in religion, their "religiosity" was also measured. Because of its focus on preserving the societal "status quo," religiosity is considered a strong feature of a more conservative mindset. Religion scholars have measured the religious commitment across regions, regardless of religion type. Religiosity tends to tie in closely with 'family values,' the degree that family connections are important in a particular community and how often family members stay in contact. After comparing this research with the "parasite stress theory of values," Thornhill found that the higher the parasite stress in a region, religiosity followed suit, with these regions showing a higher level of religiosity and 'family values.'
Gender Inequality, Child Neglect Higher
In “higher parasite stress/greater conservative value systems” communities also have greater levels of gender inequality. Men are considered superior to women. As a result men are often quicker to act out violently towards women when they perceive women acting in ways that are counter to men’s best interests. Thornhill and Fincher have reported a strong relationship between consrvatism and both lethal and nonlethal violence against women perpetrated by a male romantic partner.
Child maltreatment and neglect was another variable examined by Thornhill's team. Thornhill's team compared their research with child mistreatment data collected by the federal government and state governments around the United States.
Thornhill said, “infectious disease stress across regions is the strongest known correlate of all major types of homicides.”
They found that in places where you have a higher risk of infectious diseases there is also a greater proportion of children who their parents consider to be "sick.” Parental animals, not just humans but other mammals as well, will show "discriminative parental care,” using subconscious cues from their children to inform them of whether or not the child may survive to adulthood. Parents will adjust their care to match the chance for survival, those children seen as weak or sickly will receive less attention from their parents and may be neglected, abused or even killed.
Reducing Parasite Threats, Changing Societies?
One of the easiest ways to reduce these parasite threats, according to Thornhill, would be to provide a community with sustained modern medicine and sanitation to improve the health and well being of the community. According to Thornhill and Fincher’s research, they believe that it would be possible to change a society’s value system widely within a few generations.
"Emancipate people from parasites and you will change their values within a generation or two and you'll have a reduction in the behaviors that humanitarians think are immoral, such as violence," Thornhill mused.
As an example of this, Thornhill points to the cultural revolution for civil rights, women's rights, and gay rights in the West during the 1960s. A generation or two before the 1960s, many countries in the West embarked on a strong effort to clean up infectious diseases in their countries - from cleaning water with chlorine and adding fluoride to it, starting vaccinations programs in the 1920s, to the invention and wide availability of antibiotics such as penicillin in the years after World War II. Thornhill's research connected these early 20th century health advancements with the 1960s cultural revolution, occurring one to two generations later.
Despite expected criticisms, Thornhill insists that the science behind his research is not designed to dictate moral codes to people.
"Science’s job is to understand the causes of natural phenomenon, period." he said. "From scientific findings you can't develop a moral code. People, with their values systems, erect these moral codes. Science doesn't tell you that civil war is morally bad, or men killing each other is bad. But scientific findings can be used to achieve the moral goals separately identified by people."
