Document Type


Publication Date



We consider several forms of helping behavior among Tsimane Amerindians of Bolivia, including provision of shelter, childcare, food, sickcare, loans, advice, and cultural influence. While kin selection theory is traditionally invoked to explain nepotistic nurturing of youngsters by closely related kin, much less attention has been given to understanding the help provided to children and adults by individuals without close genetic relatedness. To explain who provides the various forms of help that we consider, we evaluate support for several predictions derived from kin selection theory: that helpers are most often closely related and from an older generation, provide more help when help is costly, favor beneficiaries with high reproductive value, and tend to be maternal kin more than paternal kin. We also evaluate support for a relationship effort explanation for help among genetically unrelated adults. We define relationship effort as the beneficent investments made in trust-based relationships, such as among unrelated friends, mates, in-laws, and exchange partners. Our results support kin selection and relationship effort explanations for who helps Tsimane children and adults.


ESI Working Paper 24-06



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.