Groundbreaking research in the controversial field of behavioral genetics suggests that the factors leading an individual to pursue any occupation, including engineering, cannot be explained as a simple tug of war between "nature" and "nurture."
The researchers are finding that vocational interests are primarily the products of genetics and unique, or nonshared, environmental factors, with shared family experiences holding less sway. The research may indicate why some individuals are predisposed to careers in engineering. It might also explain the high occurrence of autism in the families of engineers.
Wendy Johnson, postdoctoral research fellow at the University of Minnesota, is in the vanguard of the research. She and her colleagues are using structural magnetic resonance imaging (MRI) to reveal the relative placement and volume of gray matter in the brain. They are also using the technique to determine to what degree the brain is influenced by genetic vs. environmental factors.
The research into gray matter volume and its distribution has only just begun; the University of Minnesota team intends to publish its full findings in December. But preliminary results show that while verbal ability and focus orientation are widely dispersed throughout the brain (see story, this page), spatial abilities appear to be more specialized--and therefore localized--within the brain.
Rotation tests help determine spatial ability. Image C cannot be brought into congruence by any rotation.
A high degree of spatial ability, or the ability to mentally rotate objects in space, is a key trait of an engineer.
Previous studies compared the volume of gray matter in the brains of identical and fraternal twins and found the identical twins' gray matter to be twice as similar as that of the fraternal twins. That led to the conclusion that almost all of the variation in gray matter is due to genetic influences.
"The volume of gray matter in the brain is hugely heritable, like height. That's the only other trait I know that's shown that kind of pattern of similarity," said Johnson.
The autism link
Genetics also plays a role in predicting autism in families with engineering backgrounds. In the January 2006 issue of Archives of Disease in Childhood, Simon Baron-Cohen revealed that fathers and grandfathers of children with autism are twice as likely to be in the engineering field as in other occupations.
Baron-Cohen, professor of developmental psychopathology and director of the Autism Research Centre at Cambridge University, said the brains of engineers have systemizing mechanisms that are set at a higher-than-average, or hypersystemizing, level. "Normal systemizing would be being able to read the instructions on your new appliance easily, reading maps or figuring out how your new digital camera works. Hypersystemizing would be doing these things much faster and recalling all the tiny details about the new system," said Baron-Cohen.
There are eight levels of systemizing, he said. As the levels increase, the individual's ability to cope with spontaneous change severely decreases.