Cat parasites control society

"Cat parasite may control cultural traits in human populations," CogNews reports. New research published in PNAS on the brain parasite toxoplasma gondii, commonly found in cat faeces, offers some creative analysis:

Evidence for subtle long-term effects on an individual's personality, reported by researchers in the Czech Republic, inspired [Kevin Lafferty, a USGS scientist at UC Santa Barbara] to explore whether a shift in the average, or aggregate, personality of a population might occur where Toxoplasma has infected a higher proportion of individuals. Infection with Toxoplasma varies considerably from one population to another; in some countries it is very rare, while in others nearly all adults are infected. To test his hypothesis, Lafferty used published data on cultural dimension and aggregate personality for countries where there were also published data on the prevalence of Toxoplasma antibodies in women of childbearing age. Pregnant women are tested for antibodies because of the serious risk posed by toxoplasmosis to fetuses, which lack their own immune systems.

The results of previous work suggested that Toxoplasma could affect specific elements of human culture. Toxoplasma is associated with different, often opposite, behavioral changes in men and women, but both genders exhibit guilt proneness (a form of neuroticism). Lafferty's analysis found that countries with high Toxoplasma prevalence had a higher aggregate neuroticism score, and western nations with high prevalence also scored higher in the 'neurotic' cultural dimensions of 'masculine' sex roles and uncertainty avoidance.

"There could be a lot more to this story. Different responses to the parasite by men and women could lead to many additional cultural effects that are, as yet, difficult to analyze," said Lafferty.

Different research on cats and toxoplasma gondii suggests a causal link to schizophrenia. Pregnant women who are exposed to cat faeces seem to risk children developing schizophrenia later in life. Read more.

[Pictured above: cats are also learning to hack computers. Beware!]