Research press release


Nature Human Behaviour

Fewer pathogens associated with greater gender equality



Michael VarnumおよびIgor Grossmanは、米国については1951~2013年の、また英国については1945~2014年のアーカイブデータを使って、感染症、リソースの不足、戦争、気候ストレスの4つの重要な生態学的側面が、男女平等に経時的に及ぼす影響を調べた。その結果、検討した変数の中で、病原体の罹患率が、男女間の不平等と最も強い関連を示すことが明らかとなった。米国でも英国でも、病原体罹患率の変化は男女間不平等の変化に先立っていたことから、2つの変化に因果関係がある可能性が示唆された。またVarnumとGrossmanは、広い意味での伝統的な文化的規範および文化的態度によっては、病原体と男女間の不平等との関連を説明できないこと、一方で、生活史戦略が男女間不平等に対する病原体の影響を仲介していることを見いだした。すなわち感染症のレベルが低いと、人々はより緩やかな生活史戦略をとる可能性が高くなる。女性の場合、これは、教育および職業上の人生が優先されて、子どもをもうける時期が遅れることを意味する。


Reductions in the prevalence of infectious disease are associated with increases in gender equality in the United States and the United Kingdom over the past several decades, reports a paper published online this week in the new journal Nature Human Behaviour. The study suggests that efforts to reduce infectious diseases, such as vaccinations, free health care, public sanitation and water treatment, might increase equality between the sexes around the globe.

Although differences in gender equality between societies and changes within them have been well documented, the causes of shifts in levels of gender equality remain poorly understood.

Michael Varnum and Igor Grossman use archival data from 1951-2013 in the United States and from 1945-2014 in the United Kingdom to examine the effect of four key ecological dimensions - infectious disease, resource scarcity, warfare and climatic stress - on changes in gender equality over time. They find that, among the variables examined, pathogen prevalence shows the strongest association with gender inequality. In both countries, changes in pathogen prevalence preceded changes in gender inequality, suggesting a possible causal relationship. They find that more broadly traditional cultural norms and attitudes did not account for the link between pathogens and gender inequality, but that life history strategies significantly mediated the effect of pathogens on gender inequality. That is, when levels of infectious disease are low, people are more likely to adopt slower life history strategies. For women this might mean delaying reproduction in favour of pursuing education and careers.

The authors note that, although their analysis does not enable definite inferences concerning causality, it still suggests a crucial role for pathogen prevalence.

doi: 10.1038/s41562-016-0003


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