This paper seeks to explain the presence of the incest taboo, and its occasional extension to first cousins. After considering prevailing theories logically, the author conducts tests of the three prevailing theories, and concludes that inbreeding theory is both the most logically sound and is best supported by ethnographic evidence. The author subsequently addresses possible exceptions to this theory, and includes a mathematical model which suggests that early expanding agricultural populations may have been able to notice the deleterious effects of inbreeding.

This paper seeks to explain the presence of the incest taboo, and its occasional extension to first cousins. After considering prevailing theories logically, the author conducts tests of the three prevailing theories, and concludes that inbreeding theory is both the most logically sound and is best supported by ethnographic evidence. The author subsequently addresses possible exceptions to this theory, and includes a mathematical model which suggests that early expanding agricultural populations may have been able to notice the deleterious effects of inbreeding.

This paper seeks to explain the presence of the incest taboo, and its occasional extension to first cousins. After considering prevailing theories logically, the author conducts tests of the three prevailing theories, and concludes that inbreeding theory is both the most logically sound and is best supported by ethnographic evidence. The author subsequently addresses possible exceptions to this theory, and includes a mathematical model which suggests that early expanding agricultural populations may have been able to notice the deleterious effects of inbreeding.

This paper seeks to explain the presence of the incest taboo, and its occasional extension to first cousins. After considering prevailing theories logically, the author conducts tests of the three prevailing theories, and concludes that inbreeding theory is both the most logically sound and is best supported by ethnographic evidence. The author subsequently addresses possible exceptions to this theory, and includes a mathematical model which suggests that early expanding agricultural populations may have been able to notice the deleterious effects of inbreeding.

This study tests a common theory that predicts a positive relationship between exogamy and cross-allegiances between social units. Results did not support this prediction. Cross-allegiances were only weakly related to cross-cousin marriage.

This article tests the conflicting loyalties theory that predicts feuding will be absent when multiple allegiances are present. The author tests this theory using variables that are believed to establish cross-cutting loyalties, such as exogamy and cousin marriage. Several hypotheses are tested, none are supported.

This article uses alliance theory and kin selection theory to examine the relationship between consanguineous marriage and descent system. The author argues that there is no relationship between the severity of incest taboos and the rules of exogamy or endogamy. A series of testable hypotheses regarding incest, marital, and descent rules are presented.

This study tests a common theory that predicts a positive relationship between exogamy and cross-allegiances between social units. Results did not support this prediction. Cross-allegiances were only weakly related to cross-cousin marriage.

This article explores whether the practice of cousin marriage helps explain the persistence of honor cultures and honor killings. The authors have hypothesized that cousin marriage can create kin benefits but also parent–offspring conflict, leading to the evolution of honor norms and punitive practices to enforce cousin marriages. Using genomic inbreeding coefficients as a proxy for historical cousin marriage across 52 ethnic groups, these practices are likely to enforce these marriages across regions within countries. The conclusion is that honor cultures may be rooted in kinship dynamics, particularly conflicts surrounding consanguineous marriage. Authors do raise evolutionary puzzle of why female victims are harmed by blood kin.

Researchers examined kinships terminology systems for explanations regarding specifically observed typology of kin terms for cousins cross-culturally. They explore two theories, the first relating to population size via bottleneck evolution, and the second relating to social practices that shape kinship systems. Using the Ethnographic Atlas within D-PLACE, 936 societies with kinship system information were studied. The findings did not suggest a relationship between increased community size and a decrease in kinship complexity, however the research does suggest a relationship between practices of marriage and descent and kinship complexity.