Your political views may be shaped by a parasitic infection called toxoplasmosis, a new study has found. Toxoplasma gondii is one of the most widespread parasites worldwide, mainly transmitted by humans through contact with infected cats and by eating foods (particularly lamb, pork and venison) contaminated with the parasite. It is estimated that around a third of the population is infected.
“People infected by Toxoplasma gondii show no specific symptoms, but show a higher incidence of many diseases, disorders, and differences in personality and behavior,” the team wrote in their study, published in Evolutionary Psychology. “The aim of this study was to compare people’s political beliefs and values toxoplasma-infected and toxoplasma-free participants.”
The team used a survey to measure the political beliefs of 2,315 people, 477 of whom were infected toxoplasma, taking into account factors such as age, gender and the area where they lived. Compared to the control group, it was found that people with toxoplasmosis generally scored higher on tribalism and lower on cultural liberalism and anti-authoritarianism than their uninfected peers.
There were differences between male and female participants, with males being infected toxoplasma It shows a mildly negative association with tribalism, as well as an increased preference for economic justice and a less competitive society, which the researchers did not expect. Infected women, on the other hand, performed higher in tribalism and lower in cultural liberalism. Both men and women with toxoplasmosis have previously found that they perform worse on conscientiousness and generosity.
The team speculated that the differences in political beliefs could be due to poorer physical health (among infected men and women) and poorer mental health (mainly among infected women). However, when they controlled for these factors, the associations were not reduced, “suggesting that impaired health in infected individuals is not the cause of changes in political beliefs,” the authors write. “The fact that the changes in men and women are in the same direction also supports the same conclusion, since stress management-associated behavioral and personality changes tend to be in different directions in men and women.”
The team offered some possible explanations for the change, including the fact that the differences could be due to a long-term mild inflammatory response from the parasites.
“While the direction of causality needs further investigation, and while the human-related field of parasite-induced personality trait changes is unfortunately understudied and rather complex, we can expect at least some impact of infectious diseases on political attitudes induced by changes in the personality traits,” the authors write in their discussion. Given the prevalence of the disease, it could theoretically impact the political climate in countries with high infection rates.
“toxoplasma is a very widespread parasite, and therefore its prevalence (which varies greatly between and within countries) can affect not only the political climate in different countries and different social classes of the population,” study author Jaroslav Flegr told Psypost, “but also in real life – World politics and thus history.”
The study is published in Evolutionary Psychology.