From: Wade T.Smith (wade_smith@harvard.edu)
Date: Thu 17 Oct 2002 - 03:35:18 GMT
http://www.pnas.org/cgi/content/abstract/222389599v1?ijkey=f3uGSmr3wB0r.
A reassessment of human cranial plasticity: Boas revisited
Corey S. Sparks * and Richard L. Jantz
*Department of Anthropology, Pennsylvania State University, 409
Carpenter Building, University Park, PA 16802;
and Department of Anthropology, University of Tennessee, 250 South
Stadium Hall, Knoxville, TN 37996
Edited by Henry C. Harpending, University of Utah, Salt Lake City, UT,
and approved August 30, 2002 (received for review July 1, 2002)
In 1912, Franz Boas published a study demonstrating the plastic nature
of the human body in response to changes in the environment. The
results of this study have been cited for the past 90 years as evidence
of cranial plasticity. These findings, however, have never been
critiqued thoroughly for their statistical and biological validity.
This study presents a reassessment of Boas' data within a modern
statistical and quantitative genetic framework. The data used here
consist of head and face measurements on over 8,000 individuals of
various European ethnic groups. By using pedigree information contained
in Boas' data, narrow sense heritabilities are estimated by the method
of maximum likelihood. In addition, a series of t tests and regression
analyses are performed to determine the statistical validity of Boas'
original findings on differentiation between American and European-born
children and the prolonged effect of the environment on cranial form.
Results indicate the relatively high genetic component of the head and
face diameters despite the environmental differences during
development. Results point to very small and insignificant differences
between European- and American-born offspring, and no effect of
exposure to the American environment on the cranial index in children.
These results contradict Boas' original findings and demonstrate that
they may no longer be used to support arguments of plasticity in
cranial morphology.
Link to article (PDF):
http://www.pnas.org/cgi/reprint/222389599v1?ijkey=f3uGSmr3wB0r.
[thanx to]--Stephen Carville
http://www.heronforge.net/~stephen/gnupgkey.txt
Blessed are those who, in the face of death, think only of the front
sight.
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