Evolutionary Perspectives on the Nature of Sibling Conflict: The Impact of Sex, Relatedness, and Co-Residence
Our siblings can be our closest allies and yet are often our first rivals. What factors influence the nature of these relationships, and are there certain aspects that make our siblings more likely to be a source of conflict rather than solidarity? From an adaptationist perspective, sibling conflict should vary in frequency and intensity as a function of degree of relatedness. For example, conflict should be most frequent and intense between non-biological and step-siblings while conflict between full biological siblings should be least frequent and intense with half-sibling conflict being of an intermediate degree. This study examines levels of sibling conflict as a function of sex of participant, sex of sibling, degree of relatedness, and length of co-residence as well as self-reported sources of conflict. Results indicate that genetic relatedness does influence the frequency and intensity of conflict, though the most intense conflict was between non-biological siblings and the least was between half-siblings.
Evolutionary Psychological Science
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