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No. 36: Nov-Dec 1984

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Why most people are right-handed

Depending upon which estimate you believe, 6 to 16% of us are left-handed. On the surface, left-handers seem little different from right-handers. So why the highly skewed population? Why not 50% of each? Dr. Peter Irwin, at Sanddoz, Ltd., of Basle, Switzerland, has what is certain to be a controversial answer. He was led to his conclusion by a series of experiments with psychoactive drugs, performed in collaboration with Professor Max Fink, SUNY, Stony Brook. Left-handers, the study demonstrated, are much more sensitive to drugs that act upon the central nervous system. Irwin believes that this finding is consistent with the known association of left-handedness with epilepsy and learning disorders.

"But perhaps the most exciting aspect of Irwin's hypothesis is that it makes evolutionary sense. 'A greater resistance of right-handers to centrally active substances, when Man was a forager and before he learned to identify non-toxic edibles, would have favoured righthanded survival. This might account for the skew in the present handedness distribution that is unique to humans.'"

And why should left-handers be more sensitive to psychoactive substances? Irwin thinks they must absorb or metabolize them differently, or perhaps there is a difference in the blood-brain barrier that affects the transport of substances into the brain.

(Grist, Liz; "Why Most People Are Right-Handed," New Scientist, 22, August 16, 1984.)

From Science Frontiers #36, NOV-DEC 1984. 1984-2000 William R. Corliss

Science Frontiers Sourcebook Project Reviewed in:


  • "A sourcebook of unexplained phenomena is therefore a valuable addition to a collection of scientific literature. William R. Corliss has provided this in the past with his source books of scientific anomalies in several subjects, and now he has provided it for astronomy. He has done an excellent job of collecting and editing a large amount of material, taken in part from scientific journals and in part from scientific reporting in the popular or semi-scientific press." -- "The Mysterious Universe: A Handbook of Astronomical Anomalies", reviwed by Thomas Gold, Cornell University, in Icarus, vol.41, 1980

  • "An interesting, systematic presentation of unusual weather [..] This book is recommended for a general audience" --"Corliss, William R., Tornados, Dark Days, Anomalous Precipitation, and Related Weather Phenomena, Sourcebook Project, 1983.", revieweed in Choice, September 1983
  • "..the science is necessarily somewhat speculative, but Corliss's symthesis is based on reputable sources." -- "Corliss, William R. (Compiler). Lightning, Auroras, Nocturnal Lights, and Related Luminous Phenomena" reviwed by Joseph M. Moran, Univ. of Wisconsin in Science Books and Films, Sep/Oct 1983

  • "Before opening the book, I set certain standards that a volume which treads into dangerous grounds grounds like this must meet. The author scrupulously met, or even exceeded those standards. Each phenomenon is exhaustively documented, with references to scientific journals [..] and extensive quotations" -- "Book Review: The moon and planets: a catalog of astronomical anomalies", The Sourcebook Project, 1985., Corliss, W. R., Journal of the Royal Astronomical Society of Canada, Vol. 81, no. 1 (1987), p. 24., 02/1987