IAV

Incest Avoidance

Class: IV - Unknown or Disputed

EPA Total Score: 1 /100

Thornhill, N. W. (1991). An evolutionary analysis of rules regulating human inbreeding and marriage. Behavioral and Brain Sciences, 14, 247-261.

Abstract: Evolutionary theory predicts that humans should avoid incest because of the negative effects incest has on individual reproduction: production of defective offspring. Selection for the avoidance of close-kin mating has apparently resulted in a psychological mechanism that promotes voluntary incest avoidance. Most human societies are thought to have rules regulating incest. If incest is avoided, why are social rules constructed to regulate it? This target article suggests that incest rules do not exist primarily to regulate close-kin mating but to regulate inbreeding between more distant kin (especially cousin categories) and sexual relations between affinal relatives (often nonkin). Three evolutionary hypotheses about cousin marriage and affinal kin mating follow from this suggestion: (1) Rules regulating mating between affinal kin are means of paternity protection. Cousin marriage (inbreeding) is regulated because, if it occurs, it can concentrate wealth and power within families to the detriment of (2) the powerful positions of rulers in stratified societies and (3) the relatively equal social statuses of most men in egalitarian societies. Tests using the comparative method on a worldwide sample of 129 societies supported the three hypotheses. Two alternative anthropological hypotheses (derived from Freudian theory and alliance theory) failed to be supported.

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Supporting Evidence

10/100

Submitted by DJGlass

10/100

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No one has (yet) rated this source as containing any supporting Medical evidence for this EPA.

No one has (yet) rated this source as containing any supporting Physiological evidence for this EPA.

10/100

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No one has (yet) rated this source as containing any supporting Genetic evidence for this EPA.

No one has (yet) rated this source as containing any supporting Phylogenetic evidence for this EPA.

No one has (yet) rated this source as containing any supporting Hunter-Gatherer evidence for this EPA.

Supporting Evidence is evidence that suggests that this trait is an Evolved Psychological Adaptation (EPA) - i.e., that it has been shaped by natural selection to solve a particular adaptive problem.

Challenging Evidence

0/100

Submitted by DJGlass

0/100

Submitted by DJGlass

No one has (yet) rated this source as containing any challenging Medical evidence for this EPA.

No one has (yet) rated this source as containing any challenging Physiological evidence for this EPA.

0/100

Submitted by DJGlass

No one has (yet) rated this source as containing any challenging Genetic evidence for this EPA.

No one has (yet) rated this source as containing any challenging Phylogenetic evidence for this EPA.

No one has (yet) rated this source as containing any challenging Hunter-Gatherer evidence for this EPA.

Challenging Evidence is evidence that suggests that this trait is not an EPA - e.g., that it is a product of cultural learning or genetic drift, or maybe it does not exist at all. However over each line of evidence for a description.