3 - The history and geography of human handedness

Summary

This chapter presents an overview of the various sets of data that provide insight into human handedness history and geography. The history of handedness before 1800 consists almost entirely of a few isolated points, which often are illuminated only briefly through indirect evidence that has to be treated with great care. Data on handedness from the prehistoric period and pre-literate societies are necessarily indirect, take many forms, and can be difficult to interpret. A classic epidemiological method for distinguishing the effects of genes and culture is to observe migrants between two countries which differ in some characteristic. The chapter provides a clear demonstration that rates of left-handedness vary between different countries. Most explanations in biology distinguish nature and nurture, which to a large extent can be conceptualized as genes and environment. Social pressure can take many forms, and it is useful to distinguish between direct and indirect social pressure.