References 109the rapid advances in the neurosciences that have opened
new, unforeseen vistas in psychology. Further progress will
also procede apace with the development of new methodolo-
gies and the refinement of current ones.
Behavior genetics has challenged the radical environmen-
talist position by showing that nearly all personality traits and
even some broad attitudinal traits have a significant degree of
genetic determination. It is becoming a truism that genes in-
teract with environment throughout life. But the precise na-
ture of this complex interaction remains obscure. Genes do
not make personality traits; they make proteins. The develop-
ment of molecular behavioral genetics will help solve some
of these problems. When we know some of the major genes
involved with a personality trait and what these genes make
and influence in the nervous system, we will be in a better po-
sition to define the biological mechanisms that lie between
gene and behavior. Knowing the gene-biological trait link is
not sufficient until we can understand the way the biological
mechanism interacts with the environment, or more specifi-
cally the brain-behavior relationship.
Until recent decades the study of the brain was limited to
peripheral measures like the EEG. The brain-imaging meth-
ods are only in their infancy but are already influencing the
course of our science. The ones like PET or the more effective
fMRI can tell us exactly what is happening in the brain after
the presentation of a stimulus or condition, as well as where it
is happening. The expensiveness of these methods has lim-
ited their use to medical settings and to clinical populations.
Studies of personality in normals are rare and incidental to the
objectives of clinical studies. They usually involve small
numbers of subjects with a consequent unreliability of find-
ings. Sooner or later the application of these methods to the
study of personality dimensions in nonclinical populations
will help to understand exactly what a personality predisposi-
tion is in the brain. Longitudinal studies starting with genetic
and neurochemical markers and tracking the fate of individu-
als with these markers through life will enable us to predict
both normal variant outcomes and psychopathology.
REFERENCES
Almada, S. J., Zonderman, A. B., Shekelle, R. B., Dyer, A. R.,
Daviglus, M. L., Costa, P. T., & Stamler, J. (1991). Neuroticism
and cynicism and risk of death in middle-aged men: The Western
Electric Study. Psychosomatic Medicine, 53,165–175.
Archer, J. (1991). The influence of testosterone on human aggres-
sion.British Journal of Psychology, 82,1–28.
Archer, J., Birring, S. S., & Wu, F. C. W. (1998). The association
between testosterone and aggression in young men: Empirical
findings and a meta-analysis. Aggressive Behavior, 24,411–420.
Åsberg, M. (1994). Monoamine neurotransmitters in human aggres-
siveness and violence: A selected review. Criminal Behaviour
and Mental Health, 4,303–327.
Auerbach, J., Faroy, M., Kahanna, M., Ebstein, R., Geller, V.,
Levine, J., & Belmaker, H. (1998, October). Dopamine D4 re-
ceptor and serotonin transporter promoter in the determination
of infant temperament. Poster presented at 12th Occasional Tem-
perament Conference, Philadelphia.
Bagby, R. M., Levitan, R. D., Kennedy, S. H., Levitt, A. J., & Joffe,
R. T. (1999). Selective alteration of personality in response to
noradrenergic and serotonergic antidepressant medication in a
depressed sample: Evidence on non-specificity. Psychiatry Re-
search, 86,211–216.
Ballenger, J. C., Post, R. M., Jimerson, D. C., Lake, C. R., Murphy,
D. L., Zuckerman, M., & Cronin, C. (1983). Biochemical corre-
lates of personality traits in normals: An exploratory study. Per-
sonality and Individual Differences, 4,615–625.
Bardo, M. T., Donohew, R. L., & Harrington, N. G. (1996). Psy-
chobiology of novelty seeking and drug seeking behavior.
Behavioural Brain Research, 77,23–43.
Barratt, E. S. (1971). Psychophysiological correlates of classical
differential eyelid conditioning among subjects selected on the
basis of impulsivity and anxiety. Biological Psychiatry, 3,
339–346.
Barratt, E. S., Pritchard, W. S., Faulk, D. M., & Brandt, M. E.
(1987). The relationship between impulsiveness subtraits, trait
anxiety, and visual N100-augmenting-reducing: A topographic
analysis.Personality and Individual Differences, 8,43–51.
Barratt, E. S., Stanford, M. S., Felthous, A. R., & Kent, T. A. (1997).
The effects of phenytoin on impulsive and premeditated aggres-
sion: A controlled study. Journal of Clinical Psychopharmacol-
ogy, 17,341–349.
Bartussek, D., Becker, G., Diedrich, O., Naumann, E., & Maier, S.
(1996). Extraversion, neuroticism, and event-related brain po-
tentials in response to emotional stimuli. Personality and Indi-
vidual Differences, 20,301–312.
Bartussek, D., Diedrich, O., Naumann, E., & Collet, W. (1993).
Introversion-extraversion and event-related potential (ERP): A
test of J. A. Gray’s theory. Personality and Individual Differ-
ences, 14,565–574.
Benjamin, J., Ebstein, R. P., & Belmaker, R. (1997). Personality ge-
netics.Israel Journal of Psychiatry and Related Sciences, 34,
270–280.
Benjamin, J., Li, L., Patterson, C., Greenberg, B. D., Murphy, D. L.,
& Hamer, D. H. (1996). Population and familial association be-
tween the D4 dopamine receptor gene and measures of sensation
seeking.Nature Genetics, 12,81–84.
Bergman, B., & Brismar, B. (1994). Hormone levels and personality
traits in abusive and suicidal male alcoholics. Alcoholism:
Clinical and Experimental Research, 18,311–316.
Berman, M., Gladue, B., & Taylor, S. (1993). The effects of hor-
mones, Type A behavior pattern, and provocation on aggression
in men. Motivation and Emotion, 17,125–138.