Is dictatorship caused by germs?

New Scientist reports (registration required) on new research linking disease prevalence to regime type:

The starting point for Thornhill and Fincher’s thinking is a basic human survival instinct: the desire to avoid illness. In a region where disease is rife, they argue, fear of contagion may cause people to avoid outsiders, who may be carrying a strain of infection to which they have no immunity. Such a mindset would tend to make a community as a whole xenophobic, and might also discourage interaction between the various groups within a society – the social classes, for instance – to prevent unnecessary contact that might spread disease. What is more, Thornhill and Fincher argue, it could encourage people to conform to social norms and to respect authority, since adventurous behaviour may flout rules of conduct set in place to prevent contamination.

Taken together, these attitudes would discourage the rich and influential from sharing their wealth and power with those around them, and inhibit the rest of the population from going against the status quo and questioning the authority of those above them. This is clearly not a situation conducive to democracy. When the threat of disease eases, however, these influences no longer hold sway, allowing forces that favour a more democratic social order to come to the fore. […]

They rated people in 98 different nations and regions, from Estonia to Ecuador, on the collectivist-individualist scale, using data from questionnaires and studies of linguistic cues that can betray a social outlook. Sure enough, they saw a correlation: the greater the threat of disease in a region, the more collectivist people’s attitudes were (Proceedings of the Royal Society B, vol 275, p 1279). The correlation remained even when they controlled for potential confounding factors, such as wealth and urbanisation.

The article points out some flaws in the theory(the United States and Syria have nearly identical rates of disease prevalence for instance) but it seems to make some intuitive sense.  This scatter-graph is generally convincing, though from this model one might expect Turkmenistan and Bahrain to be far more free than Brazil and India. 

I’m also curious about which way the causation goes and how this squares with Amartya Sen’s ideas about authoritarian countries being less prepared to respond quickly to humanitarian crises like, say, disease outbreaks. China’s slow response and secrecy following the SARS outbreak is one example.