Kagan can foresee, in the future, his tests being applied on a wide level. "Concerned parents would take their child to the pediatrician in order to estimate the odds that he would be shy," Kagan said. However, before such a test can be administered in such a manner, it needs to be standardized, and pediatricians need to become interested in it, Kagan said.

According to Kagan, his work ushers in a new frontier in research. "There are many next steps [to my research]," he said. "There is genetics, [as well as] determining what it is that can change the disposition of a child."

Steven W. Matthysse, an associate professor of psychobiology who is pursuing genetic research related to Kagan's findings, said that Kagan's research is unique in its systematic isolation of variables related to behavioral characteristics.

Peer Praise

Kagan's colleagues were unequivocal in lauding the significance of his work. Philip S. Holzman, Rabb professor of psychology, said, "[Kagan's work] is state of the art research with an attractive feature--it effectively bridges the domains of behavior and physiology."

"In that sense, [this research] has an important statement to make on the mind-body problem," Holzman said. "It is a major contribution to our understanding of the unfolding of human development."

"What is remarkable is the connection between a psychological trait and the autonomic nervous system that Professor Kagan has uncovered," Matthysse said. "Before, it was thought that shyness was an irreducible personality trait--no one thought that it might represent an overactive nervous system."

"Work like Kagan's suggests that a chain may be uncovered linking behavioral traits like shyness to a brain function," Matthysse said.

Gardner underscored the significance of Kagan's findings by pointing out the difficulty of isolating human behavioral characteristics. "We are not measuring atomic particles or examining generations of Drosophila," he said. "We are looking at human beings in different social contexts and the temperamental variability that results."