CHAPTER 4
Biological Bases of Personality
MARVIN ZUCKERMAN
85TEMPERAMENT AND PERSONALITY TRAITS 86
EXTRAVERSION/SOCIABILITY 88
Cortical Arousal 88
Cortical Arousability 89
Monoamines 91
Monoamine Oxidase 93
Hormones 93
Summary 94
NEUROTICISM/ANXIETY/HARM AVOIDANCE 94
Autonomic Arousal 95
Brain Arousal 95
Monoamines 95
Hormones 96
Molecular Genetics 97
Summary 97
PSYCHOTICISM/IMPULSIVITY/SENSATION
SEEKING/CONSCIENTIOUSNESS/CONSTRAINT 97
Cortical Arousal and Arousability 98
Monoamines 99
Monoamine Oxidase 99
Hormones 100
Genetics 100
Summary 101
AGGRESSION/HOSTILITY/ANGER/AGREEABLENESS 102
Cortical Arousal and Arousability 102
Cardiovascular Arousal and Arousability 103
Monoamines 104
Hormones 105
Genetics 106
Summary 106
CONCLUSIONS 107
REFERENCES 109Whether we speak of mice or men, every member of a
species is the same as other members in many respects but
different in others. One task of personality psychology is to
describe the basic behavioral differences and discover their
origins. Description of personality is usually in terms of ob-
servable traits, and various models have been proposed to
classify them. Biology has confronted a similar task in the
classification of species (taxonomy). Taxonomy has been
based on phenomenal and functional similarities and differ-
ences but more recently has been moving in the direction of
using evolutionary analyses to define species in terms of their
ancestries. Psychology still depends on phenomenal similari-
ties and differences. As the genome reveals its secrets, both
fields will eventually turn to DNA for the classification task.
There are two basic pathways for the second task, the
search for the sources of individual differences. These are
shown in Figure 4.1. One pathway is the biological beginning
in behavioral genetics. Genes make proteins into neurons,
and neurons are organized into brain and nervous systems.
Neurons operate through chemical neurotransmitters and the
enzymes that govern their production and catabolism, as well
as through hormones produced in other loci. This is the bio-
chemical level. Differences in neurochemical makeup result
in differences in neural activity and reactivity or physiology.
Physiological differences affect conditionability, both of the
classical and operant types. Individuals differ in both their
conditionability and their sensitivities to conditioned stimuli
associated with reward and punishment.
The second pathway begins with the largest social unit,
culture. Cultures are subdivided into specific societies de-
fined by geography or class groupings defined by wealth, oc-
cupation, and education. Neighborhood provides the more
proximal influences on behavior. The family of origin and
peers transmit the influences of society, albeit with individual
variations on modal mores, values, and behavior patterns.
Observational learning combined with social reinforcement
is the mechanism of influence at the next level. At this point
there is a convergence of the pathways because the different