Birth order and sibling competition

Frank J. Sulloway

in Oxford Handbook of Evolutionary Psychology

Published in print April 2007 | ISBN: 9780198568308
Published online September 2012 | | DOI:

Series: Oxford Library of Psychology

 Birth order and sibling competition

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  • Psychology
  • Cognitive Psychology
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Sibling competition is widespread in the natural world, and sometimes ends in siblicide. Birth order among siblings affects the outcome of such contests, because it is a proxy for disparities in age, size, power, and opportunity. In humans, birth order combines with the prolonged period of childhood dependence on parents to promote differences in parental investment. In addition, siblings often occupy different niches within the family and employ differing tactics in competition with one another. These disparate experiences influence personality, sentiments about the family, patterns of motivation, and attitudes more generally. Birth order has also been implicated in support for, and opposition to, radical social and scientific revolutions. Although the persistence of birth-order effects in adulthood is well established by numerous studies, the extent and magnitude of these effects remains controversial.

Keywords: sibling; competition; birth order; siblicide; humans; childhood; dependence; parental investment; adulthood

Article.  9682 words. 

Subjects: Psychology ; Cognitive Psychology ; Cognitive Neuroscience

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