Human handedness and scalp hair whorl direction: No evidence for a common cause

Abstract

A much wider variation in many physical and cognitive behaviours exists among left-handers than among right-handers, which is evidence for more than one aetiology of left-handedness. Despite these findings some researchers are still attempting to link left-handedness to a single cause, most recently genetic determination, by pairing left-handedness with a presumed genetically based characteristic. One of these characteristics is scalp hair whorl, which may be clockwise, counter-clockwise (purportedly associated with left-handedness), or a reversal whorl (rare). Results of recent research in this topic are reviewed, our own findings are presented, and we conclude that there is no logical reason for, nor evidence of, a common aetiology of both hair whorl direction and handedness.

Keywords:

• Handedness
• Laterality
• Hair Whorl
• Left-handers

Acknowledgements

We are grateful to Diane A. Granville for her editing skills, and to John Delate, Associate Dean, and Joseph Blando, Computing and Telecommunication Services, both of Purchase College, for data collection aid.

Notes

¹The original study included 17 left-handers. Following the suggestion of a peer reviewer and the Editor we obtained results from an additional 49 left-handers