# Evolution of flexibility and rigidity in retaliatory punishment

> Research article (Proceedings of the National Academy of Sciences, 2017) · cited 16× · AI/ML

**Wikidata**: [openalex:W2756144379](https://www.wikidata.org/wiki/openalex:W2756144379)  
**Source**: https://4ort.xyz/entity/evolution-of-flexibility-and-rigidity-in-retaliatory-punishment