The Barí Partible Paternity Project: Preliminary Results

A Survey of Non-Classical Polyandry

“…She and her children will still have a provider who is motivated to invest in children that may be his own. This adaptation is identical to the one proposed by Beckerman et al (1998) for partible paternity. For men it represents a type of insurance for his children should he die: his co-husband will invest in his children after his death.…”

“…Father effect refers here to the consequences for the survival and well-being of a child should the biological father die and is inspired by Beckerman's research on partible paternity (Beckerman et al 1998). Partible paternity often leads to informal polyandry, which we defined earlier.…”

“…In a number of the societies that believe a child can have more than one father, men who had sex with the mother in the months prior to parturition are identified as fathers and provide paternal investment not only in terms of food but in social and political support as well. Among the Bari, Beckerman et al (1998) showed that children who had two fathers were significantly more likely to survive to age 15 than children who had one. Similar results were demonstrated for the Ache (Hill and Hurtado 1996).…”

Evolution of human mate choice

“…(Lancaster, 1989, pp. 68-69) In several South American Indian societies, such as the Ache and Barí, women will engage in sexual relations with men who are not their social partners, especially after becoming pregnant (Beckerman et al, 1998;Hill & Hurtado, 1996). By tradition, these men are called secondary fathers and are socially obligated to provide material resources and social protection to the woman's child, although not all of them do so.…”

“…With more than one secondary father paternity is too uncertain, and thus these men do not invest in the child. The benefit of a secondary father cannot be attributed to qualities of the mother, as Beckerman et al (1998) found that 80% of Barí children with a secondary father survived to adulthood compared to 61 % of their siblings without a secondary father.…”