During the Middles Ages,
decrees from the early Catholic Church triggered a massive transformation in
family structure. That shift explains, at least in part, why Western societies today
tend to be more individualistic, nonconformist and trusting of strangers
compared with other societies, a new study suggests.
The roots of that Western mind-set go back roughly 1,500 years when a branch
of Christianity that later evolved into the Roman Catholic Church swept across
Europe and beyond, report human evolutionary biologist Joseph Henrich and
colleagues in the Nov. 8 Science.
Leaders of that branch became
obsessed with what they saw as incest, the researchers say, and launched a “marriage
and family program” that eventually banned marriages between even distant
cousins, step-relatives and in-laws. Church policies also encouraged marriage
by choice instead of arranged marriages, and small, nuclear households, with couples
living separately from extended family members.
anthropological and psychological data, Henrich and his colleagues show that the
Church’s policies helped unravel the tight, cohesive kin networks that had
existed. In places under the Church’s influence, a Western-style mind-set has
come to dominate, the team says.
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“Human psychology and
human brains are shaped by the institutions that we experience and the most
fundamental of human institutions are our kinships [and] the organization of
our families,” says Henrich, of Harvard University. “One particular strand of Christianity
… got obsessed with this and altered the direction of European history.”
But behavioral economist
David Huffman of the University of Pittsburgh urges caution in interpreting the
new results. “I’m pretty convinced that they’re finding these correlations,” he
says. “I’m just not fully convinced about the causal story from kinship ties to
all these other [psychological] variables.”
Across the globe, much
variation exists among different societies’ psychological beliefs and
behaviors. But in general, individuals in European countries and other
countries of British descent tend to be more individualistic and independent
and less conforming and obedient. These societies are often described today as Western,
educated, industrialized, rich and democratic, or WEIRD for short (SN: 11/18/15). (Henrich coined the acronym in a seminal 2010 study in Behavioral
and Brain Sciences).
To understand how that
Western mind-set might have emerged, Henrich’s team started by mapping the worldwide
spread of that branch of Christianity, known as the Western Church, prior to the
year 1500, when the marriage program reached its height. The team then zoomed
in on the spread of bishoprics, or church administrative centers, across 440
regions in 36 European countries from 550 to 1500. That spread was mapped
alongside exposure to the Eastern Church, which evolved into the Orthodox
Church and did not adopt such strong taboos against “incest.”
Next, the researchers assessed
how varying levels of exposure to the church and its family policies influenced
the strength of community- and family-based institutions. For a qualitative
approach, the authors used an existing anthropological and historical database
of 1,291 populations observed before industrialization. By honing in on
elements of family structure, such as marriages between cousins, habitation
patterns and presence or absence of polygamy, the team showed that “kinship” — close ties with an extended clan beyond just
immediate family — decreased
in areas exposed to the church.
When the researchers
zoomed in on rates of marriage between cousins, they found that for each 500
years a country spent under the influence of Western Church, this type of
marriage dropped by 91 percent.
Lastly, the scientists evaluated
that transformation in family structure alongside changes in psychological
beliefs and behaviors. Drawing on existing data sources on 24 psychological metrics,
such as individualism, creativity, conformity, honesty and trust, the
researchers found that the longer a population was exposed to the Western
Church, the higher its individualism, nonconformity and trust of strangers.
This interplay between
history, family structure and psychology affects modern times, the authors say.
In Italy, for example, the Western Church’s influence was limited to the
northern and central portions of the country until well into the Middle Ages. Data
based on Vatican records show that, consequently, marriages between first
cousins were almost nonexistent in the north, but accounted for 3.5 to just
over 5 percent, on average, of all unions in the far south from 1910 to 1964,
the researchers found.
What’s more, the
country’s average blood donation rate — a proxy for trust of strangers — equaled
about 28 bags of blood for every 1,000 people, according to data from 1995. But
the authors found, for instance, that a doubling of the rate of first cousin
marriages in a given region was linked to a decline in blood donations by about
8 collection bags per 1,000 people, suggesting more distrust of strangers among
people there. Similarly, Italians from areas with higher rates of cousin
marriages were more likely than other Italians to distrust banking
institutions, preferring instead to take loans from family and friends and keep
money in cash.
One’s loyalty to extended family, or lack thereof, explains cultural variations within Italy, Henrich jokes. “The north is where the birth of the Renaissance was; the south is the birth of the Mafia.”