National differences in extraversion and neuroticism.

A method is proposed for measuring national differences in extraversion and neuroticism from demographic and epidemiological data. The method is to use national prevalence rates of a number of variables and treat them as indices of the levels of extraversion and neuroticism in national populations. The variables taken are the national rates of divorce, illegitimacy, accidents, crime, murder, suicide, alcoholism, chronic psychosis and coronary heart disease; and the per capita consumption of calories, cigarettes and caffeine. Data for these indices are presented for the advanced western nations. The relationship of these variables to extraversion and neuroticism among individuals is used to set up a model for their relationship among nations. The variables were factored by principal components analysis and this yielded two major factors identified as extraversion and neuroticism. The factor scores of each nation on the two factors were then computed. These indicate that the most extraverted nation is the United States and the most introverted is Japan. The most neurotic nation is Austria and the least neurotic is Ireland.