Progress Daily

Vera Morhenn examined whether munificence towards strangers could be manipulated through touch. In her experiment (see “Monetary sacrifice among strangers is mediated by endogenous oxytocin release after physical contact“), she split 96 male and female graduate students into three groups. The first and second received a professional massage but the third did not. Then the first and third group took part in a “trust game.”

Participants were paired at random and seated in front of a computer, physically removed from their anonymous partner. Each also got $10 in cash, supposedly for showing up. The rules stipulated that for each pair, one person, the giver, could cede a part of their money to the other, the trustee. This amount would then be tripled and credited to the trustee, who was subsequently prompted by the computer to sacrifice a part of his stash by returning some to the giver.

Morhenn took blood samples at the start and end of each game and looked for changes in oxytocin levels. She found no effect in the massaged group who did not participate in the game, implying that trust acts as some sort of trigger. But in the players the hormone rose in those who were massaged and fell slightly in those who were not.

Despite receiving statistically identical trust signals from givers, the massaged trustees with their higher oxytocin levels returned a whopping 240% more than their unrubbed counterparts. Women appear more susceptible than men to tactile manipulation.

“A touch of generosity,” The Economist

Corey Fincher and Randy Thornhill hypothesized that in places where disease is rampant, it behoves groups not to mix with one another more than is strictly necessary, in order to reduce the risk of contagion. They therefore predicted that patterns of behaviour which promote group exclusivity are stronger in disease-ridden areas. Since religious differences are in that category, they predicted that the number of different religions in a place will vary with the disease load. [See "Assortative sociality, limited dispersal, infectious disease and the genesis of the global pattern of religious diversity."]

Using accepted definitions, they calculated that the average number of religions per country is 31. The range, though, is enormous — from 3 to 643. Côte d’Ivoire, for example, has 76 while Norway has 13, and Brazil has 159 while Canada has 15. They found that the average number of parasitic diseases per country is 200, with a range from 178 to 248.

Some of the differences between countries are caused by differences in their areas and populations. But these can be accounted for statistically. When they have been, the number of religions in a place is strongly correlated with how disease-ridden it is. There is less than one chance in 10,000 that it has come about accidentally.

The researchers also looked at anthropological data on how much people in “traditional” (ie, non-urban) societies move around in different parts of the world. They found that in more religiously diverse — and more disease-ridden — places people move shorter distances than in healthier, religiously monotonous societies.

“Praying for health,” The Economist