Mother-in-law daughter-in-law conflict: An evolutionary perspective, ethnographic review, and report of empirical data from the United States
Relationships with genetic relatives have been extensively studied in the evolutionary social sciences, but affinal relationships have received much less attention, and virtually no work has examined both cooperation and conflict among affines from an evolutionary perspective. Yet humans have extensive interactions with the kin of their mates, i.e., in-laws or affines, as humans form long-term pair bonds with mates, with both sexes investing heavily in resulting offspring, thus leading to many opportunities for interacting with extended kinship networks. To begin to address the gap in scholarship on affinal bonds, and particularly on affinal conflict, we conducted an ethnographic review and collected empirical data on (cooperation and) conflict among affines. Here we present (1) a sample 37 of ethnographies showing cross-cultural evidence of conflict in affinal relationships. We also report (2) empirical evidence of self-reported (cooperative and) conflictual aspects in affinal relationships in a Western sample. U.S. men and women both reported more conflict with mothers-in-law than with mothers, and mothers reported more conflict with their daughters-in-law than with their daughters. We discuss the implications of this work and directions for future research.