WHO CARES?
The primary historical reason that the hand-brain link was considered important and became a generally-accepted methodology, was because for nearly a century it was the only hint that a neurosurgeon had prior to surgery which hemisphere was specialized for language. Clinicians used handedness as a marker for brain lateralization until the Wada (sodium amytal) Test was introduced in the 1960s.
This association between hand and brain captured the imaginations of researchers because it would be so useful (so easy, so non-invasive, so cheap) to study patterns of brain asymmetries by using a person's handedness as a marker for brain lateralization (direct methods involve neurosurgery, invasive drug testing, or expensive imaging techniques). I have argued, however, that many fundamental problems exist with this methodology, and advocate going back to the drawing board to work out some of these basic problems, rather than continue to embrace 19th-century methodology.
Better understanding how handedness relates to brain function is relevant to many people, among them: academic researchers, medical clinicians, neurological patients, educators and left-handers. Clarifying the relationship between handedness and functional brain specializations, and learning more about the developmental and neurobiological mechanisms that underlie these relationships, may help us better understand a wide range of seemingly unrelated issues such as dyslexia, stuttering, human variation, comparative brain research, developmental neurobiology of the brain, and the origins of human language.
<http://www.indiana.edu/~primate/brain.html> (Accessed: 8.7.2005)