Worldwide Diversity of Hair Curliness: A New Method of Assessment

The study aimed to objectively classify hair types based on specific shape criteria without referring to human ethnicity. Researchers measured four parameters related to hair curliness and kinking on hair from 2,449 subjects across 22 countries. Using principal components analysis and hierarchical ascendant classification, they identified eight main hair type groups. This method proved more reliable than traditional classifications and better reflected the global diversity of hair shapes, potentially aiding in tracing past mixed origins among human subgroups.