Fluctuations in national levels of neuroticism and extraversion, 1935-1970

National levels of neuroticism and extraversion in 18 advanced Western nations are measured at intervals from 1935 to 1970. It is shown that levels of neuroticism rose significantly in the nations that suffered military defeat and occupation in the Second World War and then declined during the 1950s to prewar levels. National levels of extraversion have been generally rising over this period.