Laura A. Baker1
Psychophysiological measures have been used extensively as biological markers in the study of mental processes, risk for psychiatric disorders, antisocial behavior, and reactions to stress. Yet, relatively little is known about the genetic and environmental underpinnings of most variables derived from a psychophysiological laboratory testing. The present study of twins attempted to further our understanding of the heritable and non-heritable bases of a number of psychophysiological indicators. We examined electrodermal and cardiac measures of autonomic arousal, during both rest and task situations, in 150 pairs of 9-16 year old twins. Genetic variability was found to be particularly important for baseline (i.e., during rest) measures of heart rate, skin conductance level, and non-specific skin conductance responses. Genetic variability was lower, albeit still significant, for these same variables measured while the children engaged in the continuous performance task or while listening to mild tones (i.e., during tasks). Moreover, reactivity (change between rest and task) was heritable only for electrodermal measures, including SCL and NSCR, but not for cardiac ones. Environmental factors shared by the twins were also important for electrodermal measures, which are especially sensitive to seasonal variations. These results emphasize the need for further research in order understand how genes and environment may mediate psychophysiology/behavior relationships, which will be discussed.
Address: Department of Psychology, SGM 501, University of Southern California, Los Angeles, CA 90089-1061, Phone: (213) 740-2261 FAX: (213) 746-9082 email: lbaker@usc.edu, internet: http://www-rcf.usc.edu/~lb aker/
1Department of Psychology, University of Southern California, Los Angeles, CA 90089-1061