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CHAPTER 2
A TRAIT-BASED THEORETICAL APPROACH TO
TEMPERAMENT AND STRESS
In order to ascertain the possible role of temperament and temperament traits in the
development of stress reactions, it is necessary to have a clear understanding of the
construct temperament and the roots of temperament which are historically of a
biological nature. According to Buss and Plomin (1984) the terms temperament and
personality are often used interchangeably. The difference between temperament and
personality lies in the essential foundations of individuality and its cultural evolution.
Temperament is described as behavioural traits that are heritable, although
changeable or modifiable through the course of socialisation and individual
experiences. The present chapter will firstly explicate differences in temperament and
personality according to a number of theoretical approaches, after which the historical
and modern theories of temperament will be traced. Finally the relationship between
temperament and stress will be discussed followed by an empirical validation of the
connection between temperament and stress with a chapter summary in which the
various threads are integrated.
2.1 THE DIFFERENCE BETWEEN TEMPERAMENT AND PERSONALITY The term temperament comes from the Latin word temperamentum, meaning a
mixture (of the bodily humors) and from the word temperare which means to
combine in due proportion (Rothbart, 1989). The term personality was derived from
the Latin word persona. This word was used to describe the masks worn by actors in
ancient Greek dramas (Moller, 1995). The constructs personality and temperament
are often used synonymously by various theorists such as Eysenck and Gray (Costa &
McCrae, 2001; Moller, 1995; Strelau, 1998). According to Buss and Plomin (1984)
most researchers who refer to temperament and personality as synonymous use a
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biological approach to personality where temperament describes a component of
personality structure. Buss and Plomin (1984) state that temperament differs from
personality in that temperament, unlike personality, is apparent in the early years of
life and therefore one can maintain that it is the basic building block of personality.
In order to clarify the distinction, the differences between temperament and
personality will briefly be discussed by reference to various theorists.
Strelau (1998) draws a clear distinction between temperament and personality. He
identifies a number of ways in which temperament and personality differ. Firstly, in
temperament biological factors play a stronger role than in personality, whereas
social factors play a stronger role in personality than in temperament. Furthermore,
temperament is apparent in early childhood whereas personality only manifests after
socialisation and learning have occurred. Temperament is present in other animals
whereas personality, which has cognitive features, is only observable in homo
sapiens. Temperament forms the basis of active and reactive behaviour and underlies
the levels of energy a person displays (Kagan, Snidman & Arcus, 1998; Saudino &
Eaton, 1991). According to Strelau (1998) there is a reciprocal interaction between
temperament and personality throughout the life span. Personality is more adaptable
than temperament as it acts as a regulatory function of temperament.
Rothbart (1989) describes personality as a more inclusive term than temperament in
that personality includes certain cognitive structures like self-concept, which in turn
has an influence on a person's expression of temperament throughout life
development. Personality includes an adaptive function which communicates between
a person's biological structures, cognitive structures and the demands of the
environment (Rothbart & Ahadi, 1994). For example, a person who might not be
temperamentally prone to distress might be so inclined due to certain life
circumstances, whereas a person who might be temperamentally vulnerable to anxiety
might employ certain strategies to avoid or suppress these feelings. Temperament has
also been described as comprising of emotions (Allport, 1970).
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Allport's theory of temperament has been labelled a holistic trait theory (Meyer,
Moore & Viljoen, 1997). Allport (1970) views temperament as stable traits which are
the basic building blocks of personality and have a definite genetic basis. These traits
are dependent on biochemistry and should be regarded as psychobiological (Lazarus,
1971; Strelau, 1998). Traits are enduring characteristics of an individual that serves as
an explanation for behavioural regularities and consistencies (Reber & Reber, 2001).
According to Lazarus (1971) traits refer to surface manifestations such as
aggressiveness, or deeper and more inferential qualities such as beliefs and impulse
control. Traits explain differences in anxiety, emotionality, extraversion, introversion
and stimulation seeking (Strelau, 1998). Traits are based on the functions of the
central and autonomous nervous system and the endocrine glands (Bates & Wachs,
1994, Lazarus, 1971).
Allport also refers to temperament as emotionality or emotions (Samuel, 1981).
Temperament determines the way a person reacts to emotional stimulation and the
intensity and speed of the particular reaction (Bates & Wachs, 1994; Buss & Plomin,
1984). Allport (1970, p.34) wrote:
Temperament refers to the characteristic phenomena of an individual's emotional nature, including his
susceptibility to emotional stimulation, his customary strength and speed of response, the quality of his
prevailing mood, and all peculiarities of fluctuation and intensity in mood; these phenomena being
regarded as dependent upon constitutional make-up, and therefore largely hereditary in origin.
It is clear from Allport's definition that he perceives temperament to have a biological
basis. Bates (1989) agrees with this conceptualisation of temperament as a pattern in
observed behaviour, which is based on emotions. The theory of temperament as
emotions or emotionality has been elaborated on and two distinct types have been
identified, namely: negative emotionality and positive emotionality (Strelau, 1987).
Negative emotionality is viewed as a trait that is similar to neuroticism, whereas
positive emotionality is equated to extraversion (Watson, Clark & Harkness, 1994).
Bates (1989) maintains that negative emotionality indicates tendencies toward
11
sympathetic nervous system dominance. Temperament, being part of personality
structure, has been noted by Eysenck (1965) to be more or less stable and an enduring
system of affective behaviour (emotion).
Strelau (1994) mentions a number of arguments in favour of temperament having a
biological basis. He states (in agreement with Steinmetz, 1994) that all psychological
processes involve brain activity and if there is a psychology of temperament, there
must also be a neuropsychology of temperament. Furthermore, genetic factors play a
significant role in individual differences in the expression of temperament (Calkins &
Fox, 1994). Lastly, temperament is stable (in agreement with Thomas and Chess,
1989) and distinct, as few environmental factors have an influence on early childhood
temperament traits and temperament traits have also been identified in other
mammalian species. But Strelau (1983) maintains that like all other psychological
and physiological features, temperament can change during the course of
development under environmental influence. Noise, nutrition, climate and population
density are examples of variables that could influence the shaping of temperament.
The biological conceptualisation of temperament has however developed over years
of theorising. The next section will elucidate some of the theories that have had an
influence on the understanding of temperament.
2.2 HISTORICAL AND MODERN THEORIES OF TEMPERAMENT
Theories have developed over the years as thoughts and discoveries of temperament
have been systematically formulated. Investigating the history of temperament
enables an understanding of the distinction between personality and temperament.
Strelau (1998) explicates the history of temperament by describing various theories
such as Hippocrates (the four humours) and Galen (the four temperaments). Other
theorists who have had a significant impact on the development of temperament
theory are Immanuel Kant, Wilhelm Wundt, Carl Gustav Jung, Heymans and
Wiersma, Ivan. P. Pavlov et cetera. It is clear that there are many theories relating to
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the development of temperament and personality. This section will briefly describe
the theories that form a basis for the current investigation.
2.2.1 Hippocrates and Galen
Hippocrates (ca. 460-377) has been labelled the father of medicine and he maintained
that the universe was created from four elements. These elements were earth, fire, air
and water. He then took this elemental approach and applied it to the creation of
humans and stated that they are also made from these four elements. These elements
were associated with the four humors in the body. The earth was associated with
black bile, air with yellow bile, fire with blood and water with phlegm. These four
humors would essentially determine whether a person was healthy or ill (Hergenhahn,
1997). Galen (ca. 130-200) developed the first classification of temperament using
the four humors that were proposed by Hippocrates (Rothbart, 1989). Galen
described nine temperaments falling into two categories namely primary (ordinary)
and secondary (derivative) temperaments. The four primary temperaments depend
directly on the dominance of warmth, cold, moisture and dryness. The secondary
temperaments were labelled as warmth-dryness, warmth-moisture, cold-dryness and
cold-moisture. The ninth temperament was seen as the ideal temperament which
consisted of a mixture of temperament types (Strelau, 1998). The four primary types
of temperament were known as sanguine, choleric, melancholic and phlegmatic
(Zuckerman, 1991). Other theorists later linked these temperaments proposed by
Galen to extraversion-introversion and neuroticism (Eysenck, 1965). Galen and
Hippocrates provided a basis for a physiological explanation of individual differences
in behaviour (Stelau, 1998). Many theories of temperament still refer to classical
theories as their bases. The modern theories are mostly based on the basic
conceptualisations formulated by earlier theorists. The theories of Eysenck, Gray and
Zuckerman can be regarded as biologically-based western temperament theories and
Eysenck’s hierarchical model will now be discussed.
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2.2.2 Eysenck’s hierarchical model
Eysenck proposed two related, but conceptually distinct, explanatory theories, namely
inhibition theory and arousal theory. The main aim of his inhibition theory was to
provide a theoretical understanding of the difference between introverts and
extraverts. This theory conceptualised performance differences between the two
temperament traits as greater excitation in introverts than in extraverts, or greater
inhibition in extraverts than in introverts. After increasing evidence of the theory's
paucity he formulated the arousal theory, which had the advantage of identifying the
physiological system underlying individual differences in extraversion and
neuroticism (Eysenck & Eysenck, 1985). It is the latter theory from which the three
temperaments proposed will be discussed.
Eysenck utilised various historical conceptualisations of temperament and personality
during the formulation of his temperament theory. Eysenck's theory is based on three
foundations namely: that temperament has a biological basis (Eysenck, 1982), that
temperament traits are universal and that there are three basic structures to
temperament (Eysenck, 1982). Eysenck (1956) conducted a study using factor
analysis on soldiers in an attempt to determine the elements contributing to the
structure of temperament. He found neuroticism and hysteria in the breakdown of
extraverts, and dysthymia was located in the breakdown of introverts. The three
factors, namely extraversion-introversion, neuroticism-stability and psychoticism-
normality which Eysenck identified, were primary factors that are mutually
orthogonal (or uncorrelated) (Zuckerman, 1991).
Eysenck continued to use the extraversion-introversion temperaments as postulated
by Jung (1875-1961). Jung regarded introversion and extraversion as the two major
attitudes or orientations of personality. These attitudes find expression in the
functions of thinking, feeling, sensing and intuiting. Jung describes the extravert as
seeking social approval, whereas the introvert's activity is mainly in the mental and
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intellectual sphere (Eysenck & Eysenck, 1985). Eysenck's theory on extraversion-
introversion is linked to classical conditioning, as individual differences in
temperament influence the process of conditioning (Strelau, 1983). Moreover,
Gross's neurophysiological explanation of primary-secondary function also had an
impact on Eysenck's theory as Gross perceived temperament to be the non-cognitive
dimension of personality (Eysenck, 1965). Eysenck's three factors are very broad,
and can be regarded as types or "superfactors". Sociability and impulsivity are two of
the traits forming part of the extraversion-introversion temperament (Eysenck, Green
& Hayes, 1994).
The three temperaments proposed by Eysenck were based on Hippocrates and Galen's
theoretical conceptualisations (Zuckerman, 1991). These three temperaments have
high heritability rates (Eysenck, 1990) and are transcultural (Jang, McCrae,
Angleitner, Riemann & Livesley, 1998), which indicate that certain genetic factors
cause differences in temperament (Eysenck, 1982). The three temperament traits are
part of the individual's physical constitution permanently affecting behaviour
(Eysenck & Eysenck, 1985). Eysenck, Green and Hayes (1994) explain this by
stating that if heredity is important in the three temperaments proposed by Eysenck,
then monozygotic or identical twins should resemble each other more in temperament
than do dizygotic or fraternal twins, who are no more alike in terms of heredity, than
are ordinary siblings. Extraversion-introversion, neuroticism and psychoticism are
discussed below in more detail.
2.2.2.1 Extraversion-introversion
According to Eysenck (1956, 1973) extraversion is related to being talkative, alive,
dominant, sensation-seeking and carefree (Buss & Plomin, 1984; Zuckerman, 1991).
Extraversion has a strong genetic basis (Eaves & Eysenck, 1975) and is composed of
traits such as sociability, liveliness, activity, impulsiveness and assertiveness. These
components have an influence on the manner in which a person reacts to situations
15
(Emmons & Diener, 1986; Stelmack, 1990). Vollrath (2001) elaborates by stating
that individuals who score high on impulsiveness, tend towards both stimulating and
high-risk behaviours and are vulnerable to eventually experience high levels of stress.
The extraverted person is characterised by leadership, initiative and readiness to
assume responsibility, whereas the introverted person is seen as persistent, co-
operative and careful (Eysenck, 1956). The sociability component of extraversion is
responsible for the relation between extraversion and positive affect. Watson and
Clark (1992) distinguish between positive and negative affect as being highly
distinctive dimensions that are largely independent on one another. Positive affect is
related to the frequency of pleasant events and to indices of social activity and
interpersonal satisfaction. Watson and Clark (1992) describe health complaints,
perceived stress, and the frequency of unpleasant events as being consistently related
to negative affect. Miller (2003) found that high negative affect is a primary
temperament risk factor for the development of Posttraumatic Stress Disorder
(PTSD). The level of happiness of extraverts has been investigated by Argyle and
Lu (1990) who found in their sample of 131 students (56 females and 75 males) that
extraverts enjoyed social activity and that this sociability was the reason for their
overall happiness. According to DeNeve and Cooper (1998) and Rusting and Larson
(1997) extraversion can be equated to positive affect and high subjective well-being.
In turn, Costa, McCrae and Zonderman (1987) support that well-being is strongly
influenced by enduring characteristics of the individual, like temperament.
As previously stated, Eysenck used inhibition and arousal theory to determine the
physiological aspects related to extraversion (Strelau, 1994). According to these
theories, individuals differ in their rapidity and energy of produced excitation and
inhibition, due to differences in levels of activity in the corticoreticular loop (Eysenck
& Eysenck, 1985). Individuals will vary in the speed at which the inhibition
disappears. According to Eysenck (1965), extraverts will develop excitatory
behaviour slowly and weakly, while their reactive inhibition is generated rapidly and
strongly, which then dissipates slowly. He linked cortical arousal to the individual
16
differences in extraversion and introversion. Introverts have higher levels of activity
in the corticoreticular loop (ascending reticular activating system) than extraverts and
are thus chronically more cortically aroused (i.e. activity in the brain). Thus,
extraverts are chronically less aroused than introverts (Stelmack, 1990).
Reasonable support for the view that introverts are more cortically aroused than
extraverts are found from electroencephalography (EEG, i.e., brain wave activity)
studies. Savage (1964) investigated electro-cerebral activity and its relation to
extraversion and neuroticism. The subjects consisted of 20 females who completed
the Maudsley Personality Inventory prior to EEG measurement. The results indicated
that extraverts had higher alpha amplitudes than introverts. Extraverts, therefore,
have greater cortical inhibition.
More recently, Fink and Neubauer (2004) supported Eysenck's hypothesis of more
cortical activation in introverts compared to extraverts. Their subjects consisted of 58
males and 30 females. They measured the extent of event-related desynchronization
in EEG performance of a numbers test, which consisted of five increasingly complex
conditions that vary in terms of the number of mental operations needed to be
performed successfully. To measure introversion and extraversion they used the Big
Five factors (NEO-FFI, by Costa and McCrae). They found that when the test
conditions were easy, the introverts indicated lower cortical activation compared to
the extraverts. During the more complex tasks, the introverts indicated higher
cortical activation compared to the extraverts. This study confirms what was
previously found by Savage (1964). Furthermore, the study also generates a new
dimension to the aspect of cortical arousal in that it identifies a specific situation in
which introverts will have higher cortical activation.
Researchers have also been able to predict individual susceptibility to disorders, such
as depression, by using brain wave activity. This has led to EEG studies showing that
if an individual's activation is higher in the left frontal lobe they tend to be more
17
optimistic, less susceptible to mood disorders and more stress resilient (Brain waves
and personality, 1994). Eysenck, Green and Hayes (1994) state that it may be that
introverts often show better conditioning than extraverts because their high level of
cortical arousal means that their nervous systems form the necessary associations
more readily.
The relationship between anxiety and extraversion/introversion has been described by
Eysenck (1965). Later, a South African researcher, Templer (1971, 1972)
investigated this relationship and found that there exists a definite negative
relationship between extraversion and anxiety. More recently, Strelau (1998) found
that students with high cortisol levels presented high levels of both anxiety and
depression while scoring lower on extraversion when compared with students with
low cortisol levels. He also studied war veterans and found that veterans with high
levels of cortisol measured higher on anxiety and introversion compared to low-
cortisol veterans.
2.2.2.2 Neuroticism-stability
According to Eysenck (1956, 1965) high neuroticism is characterised by features of
anxiety, depression (Dugan, Lee & Murray, 1990), feelings of guilt, low self-esteem,
tenseness, irrationality, moodiness, worry, fearfulness, obsessive indecision and being
very sensitive to others' opinions (Gomez & Francis, 2003; Holmes, Williams &
Haines, 2001; McFarlane, 1988; Zuckerman, 2002). Neuroticism is also connected to
the temperament trait of emotionality (Buss & Plomin, 1984). Eysenck and Eysenck
(1985) mention an open-field test done on rats which indicated that the trait of
emotionality is highly heritable, related to hormonal secretions, the size of the adrenal
glands and neuroticism. Neuroticism is related to the activities of the autonomic
nervous system and the central nervous system's hippocampus, amygdala, cingulum,
septum and the hypothalamus which lie within the visceral brain (Strelau, 1998). The
visceral brain (limbic system) appears to be largely concerned with emotion.
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Furthermore, the visceral brain and the Ascending Reticular Activating System
(ARAS) are only partially independent of each other, and one of the methods in
which cortical arousal can be produced is through activity in the visceral brain which
reaches the reticular formation through collaterals. Activity in the visceral brain
produces autonomic arousal activation (Eysenck, 1965). People who are high in
neuroticism produce activity in the visceral brain more readily than those low in
neuroticism (Eysenck & Eysenck, 1985). The autonomic system is involved in
somatic expression of emotional states through the sympathetic branch. Prolonged
arousal has been clearly related to physical and mental health problems (Strelau,
1998). According to Eysenck, Green and Hayes (1994), individuals who are high in
neuroticism, report many more physiological symptoms - such as rapid heart rate and
indigestion - than those who are low in neuroticism.
Individuals who are high in the neuroticism trait are consistently more prone to
developing stress-related disorders after experiencing traumatic events like exposure
to combat, earthquakes and HIV-diagnosis (Aldwin, Levenson, Spiro III & Bosse,
1989; Vollrath & Torgersen, 2000; Vollrath, Torgersen & Alnaes, 1995). Individuals
who are high in neuroticism tend to experience more distress across time, regardless
of the situation (Engelhard, van den Hout & Kindt, 2002) and are more prone to the
development of stress-related disorders after experiencing traumatic situations such as
combat, earthquakes and HIV-diagnosis (Gershuny & Sher, 1998). War veterans
who develop stress disorders after returning from combat measure higher in trait
anxiety and depression, which are important aspects related to neuroticism (Henning,
1999). Neuroticism also leads to poorer outcome in depression (Duggan, Lee &
Murray, 1990).
In a highly regarded study, Pedersen, Plomin, McClearn and Friberg (1988)
investigated the temperament traits of neuroticism, extraversion, impulsivity and
monotony avoidance in adult twins reared apart and reared together. They aimed to
determine the role of genetics versus the environment in the expression of
19
temperament. The sample consisted of 328 pairs of twins reared apart and 372 pairs
of twins reared together. Of the twins reared apart, 99 were identical and 229 were
not identical. Of the twins reared together, 160 were identical and 212 were not
identical. The average age of the sample was 58.6 (SD=13.6) as the age structure
allows for assessment of heritability in a sample of older adults. The psychometric
questionnaires used for the study included the short form of the Eysenck Personality
Inventory, which measures extraversion and neuroticism. The standard Swedish
scales of impulsivity and monotony avoidance, called the Karolinska Scales of
Personality, were included. These scales correlate with Zuckerman's constructs of
boredom susceptibility and sensation-seeking.
The manner in which the twins were located for the study employed the population-
based Swedish Twin Registry. The researchers controlled for the sample of twins
reared together drawn from the register by matching for date of birth, gender and
country of birth. A zygosity questionnaire was administered by asking questions
relating to childhood similarity and questions related to adult similarity. The sample
indicated a negative correlation between extraversion and neuroticism (r=-.31). Both
impulsivity and monotony avoidance were moderately related to extraversion but less
so to neuroticism.
The results indicated that the proportion of variance attributable to all genetic sources
(heritability) was 0.41 for extraversion, 0.31 for neuroticism, 0.23 for monotony
avoidance and .045 for impulsivity. These results suggest that genetic factors may be
less important later in life compared with early life. The authors did however state
that genetics played an important factor in the four constructs measured, although
according to life-span theorists the importance of genetic effects will decrease with
age.
The study shows that the temperament traits of neuroticism and extraversion, as
suggested by Eysenck, have strong genetic factors and are thus biologically
20
determined, but also that environmental factors have an influence on these
temperament traits, especially later in life (Pedersen, Plomin, McClearn & Friberg,
1988). Furthermore, the researchers maintain that most of the environmental variance
indicated was of a non-shared variety. In conclusion, the study shows that the
environment might play a larger role in temperament expression later in life
compared with earlier in life. The genetic versus environmental bases of
temperament is of relevance for the present study in that it indicates the importance of
biological mechanisms in temperament, but also the importance of the individual's
environment.
2.2.2.3 Psychoticism-normality
The psychoticism trait is characterised by aggressiveness, impulsiveness (Zuckerman,
Kuhlman & Camac, 1988), coldness, egocentrism, impersonality, antisocial
behaviour, creativeness and stubborness (Zuckerman, 1991). According to Eysenck
and Eysenck (1975) a person who scores high on this temperament trait could be
described as being solitary, not caring for people, the person is often troublesome and
an outcast. This individual might be cruel and inhuman, lacking in feeling and
empathy. This person is most probably hostile and aggressive to others, including
loved ones. Eysenck, Green and Hayes (1994) maintain that the psychoticism
dimension can be regarded as the individual's predisposition to a psychotic
breakdown, and they explain this by referring to the generally high scores of
schizophrenics in this temperament dimension.
Psychoticism has been found to have high heritability rates corresponding to those of
extraversion and neuroticism (Strelau, 1998). Some biological markers such as
platelet monoamine oxidase (MAO) activity have been found to be related to
psychoticism, which is associated with a kind of dissociation of central nervous
system activity (Zuckerman, 1994). This is possibly due to a weakened excitatory
and inhibitory regulation in the nervous system (Strelau, 1998).
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According to Dilalla, Gottesman and Carey (2000) psychoticism loads on factors
such as being Agreeable, Conscientious, Impulsiveness and Sensation-seeking.
Eysenck and Eysenck (1978) conducted research to measure the temperament traits of
impulsiveness, venturesomeness (sensation-seeking) and empathy. They
administered a 63-item questionnaire for the measurement of three primary
personality traits; impulsiveness, venturesomeness and empathy and the Eysenck
Personality Questionnaire, which measured psychoticism, extraversion and
neuroticism. Their sample consisted of 402 adult male subjects and 787 adult female
subjects. Using factor analysis the researchers could indicate various correlations
between the traits measured. By looking at the positive and negative correlations, one
can create a broader understanding of the three primary temperaments proposed by
Eysenck. The results showed that venturesomeness and impulsiveness correlated
positively with psychoticism and extraversion. However, venturesomeness correlated
negatively with neuroticism whereas impulsiveness correlated positively with
neuroticism. Empathy correlated positively with neuroticism. Not only does this
study show how Eysenck formulated his three "primaries", but it also indicates a
better understanding of the three "primaries" called psychoticism, extraversion and
neuroticism. More specifically, with regard to psychoticism, the study shows that
this temperament trait has features of both sensation-seeking and impulsiveness
embedded within it.
This section described the temperament constructs proposed by Eysenck. It is
evident from the above literature that the three temperament dimensions proposed are
biological in nature and consist of various defining dimensions. Eysenck's theory
plays an important role in the conceptualisation of temperament and many later
theorists used Eysenck's constructs as a basis for their own theories. Another theorist
who contributed to the understanding of temperament as a biological and stable
construct is Gray. His theory will now be discussed.
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2.2.3 Neuropsychological model of temperament developed by Gray
Jeffrey Alan Gray (1972) was one of Eysenck's students who attempted to elaborate
on the extraversion and neuroticism concept proposed by his mentor. Eysenck's
interpretation of extraversion was based on work done by Pavlov, which focussed on
excitation and inhibition (Rothbart, 1989). Gray (1987) used neurophysiological,
pharmacological and biochemical research to develop his theory of temperament.
Gray explained excitation in terms of arousal and arousability. Arousability refers to
individual differences in the organismic determinants of arousal, which lead to
individuals having a chronic (more or less stable) level of arousal. Gray’s concept of
arousability explicates the following temperament dimensions: extraversion-
introversion, neuroticism, emotionality, impulsivity, inhibited-uninhibited
temperament, approach-withdrawal and anxiety. Gray explained temperament
dimensions as states of the Central Nervous System (Gray, 1987). The temperament
dimensions proposed by Gray - neuroticism and introversion-extraversion - will
briefly be discussed, as well as the specialised systems in the brain that describe the
behaviour that determines temperament.
2.2.3.1 The temperament dimensions proposed by Gray
Gray (1987) studied classical and operant conditioning extensively. His research on
rats enabled him to identify individual sensitivity to reward and punishment in
classical and operant conditioning. Gray (1979) for example, investigated
emotionality in male and female rodents, where he found that the males were more
emotional than the females. Based on his research on animals, he developed a
neuropsychological theory of human temperament (Strelau, 1998). His theory
describes introversion-extraversion and neuroticism.
According to Gray (1987) neurotics are highly introverted and they have strong
emotions which are easily aroused. Watson and Clark (1984) equate neuroticism with
23
negative affect. They found that high negative affect leads one to experience
discomfort at all times even in the absence of overt stress. Neuroticism has been
related to reports of stress even if stressful events are absent (Vollrath, 2001). Gray
described introversion-extraversion and neuroticism from a biological approach,
indicating the various biological systems underlying these temperaments.
Gray (1972) concluded after many of his research projects that introverts are more
sensitive to punishment and nonrewards than extraverts. Gray says (1972, p.19): "…
it follows that we may regard the dimension of introversion-extraversion as a
dimension of susceptibility to punishment and nonreward: the greater the degree of
introversion, the greater is this susceptibility." He describes the biological basis of
this temperament type: The degree of a person's introversion is determined by activity
in the orbital frontal cortex, hippocampus, medial septal area and the reticular
activating system. The higher the sensitivity of these systems, the higher the
individual's introversion; the lower the sensitivity, the higher the extraversion. The
introvert is likely to develop fears due to high cortical activity which is associated
with this temperament type. Extraverts are more sensitive to rewards and
nonpunishment than are neurotics, who are generally sensitive to rewards and
punishment (Gallagher, 1990; Rothbart, 1989). Gray postulated that extraversion
could be defined as a trait consisting of low anxiety and high impulsivity, whereas
neuroticism consists of high anxiety and high impulsivity (Rothbart, 1989; Strelau,
1998).
Eysenck and Eysenck (1985) list several ways in which Gray's theory and Eysenck's
theories are similar. Their theories both focus on the same two-dimensional
temperament space. Both their theories are able to account for performance
differences between introverts and extraverts. Introverts who are exposed to
punishing stimuli are predicted to be more aroused than extraverts, either because
they are chronically more aroused or because they are more susceptible to
punishment. What makes Gray's theory applicable to the current study are his three
24
proposed physiological systems from which different temperaments stem. Gray
describes emotions and arousal in terms of functions of certain brain systems.
2.2.3.2 Gray's three physiological systems
Gray (1972) researched temperament as states of the central nervous system. He
stated that emotions are generally evoked from three systems within the brain, which
determine behaviour. The systems form the neurological basis for the three
temperament dimensions proposed by Eysenck, and are responsible for individual
differences in temperament. These three systems are the Behavioural Inhibition
System, Behavioural Activation System and the Flight or Fight System (Bates &
Wachs, 1994; Rothbart, Derryberry & Posner, 1994; Steinmetz, 1994). Gray
explicated the functioning of the three neurological systems in terms of susceptibility
to punishment and reward (Larsen & Ketelaar, 1991). By briefly describing the three
systems proposed by Gray, a deeper understanding is gained regarding the biological
bases of certain temperament dimensions.
The Behavioural Inhibition System is responsible for the awareness of signals of
punishment and non-reward. This system is accountable for the various reactions to
stimuli, and is accompanied by a subjective state of anxiety. There exists a
comparator system within the Behavioural Inhibition System, which allows the
organism to receive information from the current situation. The individual uses
stored information to comprehend past regularities and then compares them with the
present. This process enables the individual to predict certain components about a
future event by examining whether there is a match or a mismatch. The system will
come to a stand-still if there is a mismatch (Gray, 1987). The function of this system
is to suppress existing but maladaptive behaviour patterns while scanning the
environment for possible alternative behaviour patterns (Gray, 1978). The structures
related to this system are the septohippocampal system, which consists of the
hippocampal formation, the septal area and the Papez circuit (Gray, 1987). The
25
Papez circuit is highly involved in many aspects of emotions (Groves & Schlesinger,
1979). The various pathways of the system are activated during stress-inducing
situations (Gray, 1987). The hippocampus forms part of the septohippocampal
system, which is implicated in memory. This leads to a possible difference in
memory functioning between introverts and extraverts (Steinmetz, 1994). Howarth
and Eysenck (1968) investigated differences in memory and contended that introverts
have a powerful long-term memory, whereas extraverts have greater short-term
memory.
Individuals with highly reactive Behavioural Inhibition Systems are more prone to
develop personality disorders after traumatic life events than individuals with low-
reactive Behavioural Inhibition Systems (Gershuny & Sher, 1998). The reason is that
this system is responsible for withdrawal when the individual is in certain threatening
situations. Therefore, negative affect (like anxiety and depression) correlates with
inhibited behaviour (Nelson, 1994). McFatter (1994) investigated predicting mood
from extraversion and neuroticism. He found that both positive and negative affect
are strongly related to extraversion in neurotic subjects. Therefore, neurotics' arousal
levels are highly responsive to information from either the Behavioural Inhibition
System or the Behavioural Activation System and there is an interaction between
extraversion and neuroticism in predicting mood.
Rusting and Larsen (1997) compared Gray's model with Eysenck's model regarding
the relationship between extraversion and neuroticism and susceptibility to positive
and negative affect. Their sample consisted of 150 students (75 men, 75 women) and
they used imagery tasks to influence mood. Positive and negative mood states were
measured by 10 positive and 10 negative affect items from the Positive and Negative
Affect Schedule (Rusting & Larsen, 1997). The Eysenck Personality Questionnaire
measured extraversion and neuroticism. They found substantiation for Eysenck's
model in that extraversion was positively related to positive affect, following pleasant
mood induction. Neuroticism was positively related to negative affect following
26
negative mood induction. They found no extraversion X neuroticism interaction as
proposed by Gray's model. Eysenck's model is also supported by a study done by
Watson and Clark (1992) and DeNeve and Cooper (1998) who found neuroticism to
be the strongest predictor of negative affect and extraversion to predict positive
affect.
The Behavioural Activation System is mostly related to the temperament trait of
extraversion where behaviour is enforced by positive reinforcement and positive
emotionality. The structures related to this system are the basal ganglia,
dopaminergic fibres, thalamic nuclei and neocortical areas (Gray, 1987). Larsen and
Ketelaar (1991) tested the relation between Gray's Behavioural Inhibition System and
Behavioural Activation System and the temperament traits of extraversion and
neuroticism. They hypothesised that if Gray's theory were correct regarding the
differential susceptibility to affective states, then their results would indicate that
extraversion is associated with sensitivity to positive (but not negative) affect and that
neuroticism is associated with sensitivity to negative (but not positive) affect. Their
sample consisted of 359 students in an introductory Psychology course. They
administered the Eysenck Personality Questionnaire, which provided them with
extraversion and neuroticism scores. They then used a standard laboratory mood
induction procedure (guided imagery) to manipulate positive, neutral and negative
affect. They exposed 145 subjects to the negative-affect condition, 70 to the neutral-
affect condition and 144 to the positive-affect condition. After the laboratory testing
procedure they assessed emotional responsiveness using the Standard Mood
Adjective Rating Task. Their results corroborated Gray's theory in that the
Behavioural Inhibition and Behavioural Activation System both have a vulnerability
or susceptibility to specific affective states. Neurotics showed increased emotional
reactivity to the negative-mood induction, whereas the extraverts showed heightened
emotional reactivity to the positive-mood induction.
27
The third system Gray (1987) proposes is the Fight or Flight System, which is
implicated in the manifestation of anger in homo sapiens. This system is
characterised by defensive aggression and escape behaviour. It consists of the
amygdala, medial hypothalamus and central gray (Gray, 1987; Strelau, 1998). The
Fight or Flight System is responsive to unconditioned punishment and non-reward
(Gray, 1978).
Gray's model explicates individual differences as interactions between emotional
systems. He used his three proposed emotional systems to predict various structures
of human temperament. The differences in the Behavioural Inhibition System
function might correspond with trait anxiety; differences in the Behavioural
Activation System would lead to behaviour that is driven by positive reinforcement;
and the accompanying pleasurable emotions and the Flight or Fight System might
lead to aggressive defensive behaviours (Steinmetz, 1994). Table 3.1 indicates
distinct differences between two levels of arousability where most of the
temperament traits previously discussed would fit in.
28
Table 2.1 Discriminatory factors between temperament traits using high
arousability and low arousability as separators (Strelau, 1994).
HIGH AROUSABLITY LOW AROUSABILITY
Introverts
Neurotics
High emotionality
Sensation avoiders
Weak type of Central Nervous System
High reactivity
High-anxiety individuals
Low impulsiveness
Inhibited temperament
Withdrawal tendency
Extraverts
Emotionally stable
Low emotionality
Sensation seekers
Strong type of Central Nervous System
Low reactivity
Low-anxiety individuals
High impulsiveness
Uninhibited temperament
Approach tendency
Gray's theory of temperament as states of the Central Nervous System indicates a
definite biological basis for temperament. It suggests that there are various intricate
interacting neurological systems involved in individual temperament. His theory is of
relevance for the current investigation in that it adds to the understanding of
individual responses in stressful situations. It also explicates individual behaviour
prior to a stressful situation as well as why and how certain individuals will react
after having experienced a stressful encounter. Another theory that argues a strong
biological basis of temperament and is relevant for the present study is that of
Zuckerman, which will now be discussed.
2.2.4 Zuckerman's biologically-based theory of temperament
Marvin Zuckerman found in his research that individuals react differently in
conditions of sensory deprivation. An individual's reaction is based on the need for
external stimulation (Zuckerman, Buchsbaum & Murphy, 1980). Some individuals
29
are resistant to sensory deprivation whereas others present a stress response to the
situation. Zuckerman identified five basic personality factors namely: impulsive
sensation-seeking, neuroticism-anxiety, aggression-hostility, activity and sociability
(Zuckerman, 1991). These five factors have been labelled "The Alternative Five"
which describe individual differences in behaviour when in a stressful situation
(Vollrath, 2001). These five temperament traits will now be briefly discussed.
2.2.4.1 Sensation-seeking
Zuckerman's theory (1991) on sensation-seeking was mostly influenced by Gray's
neuropsychological model of individual differences in anxiety and impulsivity and
Eysenck's biological basis of extraversion (Buss & Plomin, 1984). This trait of
sensation-seeking includes various categories namely: thrill and adventure seeking,
experience seeking, disinhibition and boredom susceptibility (Zuckerman, 1971).
This corresponds to Freixanet's (1991) finding that the personality traits that mostly
predict a subject's engagement in high physical risk activities are seeking thrill,
extraversion, emotional stability and conformity to social norms. Zuckerman (1990)
defines the sensation-seeking trait as the willingness of an individual to take certain
risks in order to satisfy a craving for intricate and novel stimulation. This particular
sensation which the individual craves, does not necessarily consist of a physical
challenge but could indicate a need for the psychological meaning of the challenge.
Horvath and Zuckerman (1993) found that sensation-seeking is a strong predictor of
risky behaviour, including criminal behaviour and social violations.
Zuckerman (1994) states that sensation seeking is associated with alcohol abuse and
illegal drugs, rule violation behaviours and speeding or reckless driving. Sensation
seekers tend to engage in various types of sexual behaviour with different partners.
Furthermore, the social behaviour of sensation seekers are characterised by high
levels of verbal and non-verbal positive social affect through eye-gaze, smiling,
laughing, vocalising and self-disclosure when compared with low sensation seekers.
30
Sensation-seeking is a stable and early appearing trait (Bates & Wachs, 1994).
Sensation-seeking is usually higher in males than females and decreases with age and
is related to the gonadal hormones (Rushton, Fulker, Neale, Nias & Eysenck, 1986;
Zuckerman, Buchsbaum & Murphy, 1980). Zuckerman, Eysenck and Eysenck
(1978) found in their study investigating sensation-seeking in England and America,
that in both countries males scored higher than the females on the total sensation-
seeking score. They also found significant age declines for the sensation-seeking trait
in both sexes, but especially on the traits of thrill and adventure seeking and
disinhibition.
Individual differences are determined by the reactivity of the central nervous system
and the autonomic nervous system (Bates, 1989). Zuckerman focussed on the central
monoamine systems in determining individual differences in the trait of sensation-
seeking as platelet monoamine oxidase (MAO) levels are reliable and stable measures
of individual differences (Strelau, 1998). MAO is a neutral enzyme, which tends to
reduce central neural reactivity, particularly in the limbic system (visceral brain), by
inactivating the monoamines norepinephrine, dopamine and serotonin (Fulker,
Eysenck & Zuckerman, 1980). The sensation-seeking trait is negatively correlated
with MAO activity and this pattern has been found to be true in both humans and
monkeys (Zuckerman, 1991). Zuckerman (1991) suggests that low MAO is a positive
indicator of serotonergic activity as it plays an inhibitory role. High sensation seekers
need high levels of stimulation to preserve optimal arousal levels. Sensation evaders
require low levels of stimulation in order to maintain the same level of arousal seen in
high sensation seekers (Strelau, 1998; Zuckerman, 1991). According to Zuckerman
(1991) high sensation seekers are characterised by chronically low levels of dopamine
and norepinephrine and thus have to seek intense stimuli, which would then increase
these levels. On the other hand, sensation evaders have high levels of dopamine and
norepinephrine, which explains their behaviour to avoid high levels of stimulation.
Noradrenergic arousal may be more important in arousal of negative affect such as
depression and anxiety.
31
Fulker, Eysenck and Zuckerman (1980) investigated the genetic and environmental
contributions to the trait of sensation-seeking. Their sample consisted of 422 adult
volunteer twins who completed the Sensation-seeking Scale. The twin sample sizes
consisted of 174 pairs of monozygotic females, 59 pairs of monozygotic males, 112
of dizygotic female, 26 dizygotic male and 51 dizygotic unlike-sex pairs. The results
indicated a variance of 58 percent in the total Sensation-seeking score, which
indicated a predominantly additive gene action controlling the general trait. This
finding supports the influence of low MAO activity and gonadal hormones in the
Sensation-seeking trait as they are governed by genetics. The next section explicates
the impulsivity trait proposed by Zuckerman.
2.2.4.2 Impulsivity
Another temperament trait proposed by Zuckerman is impulsivity. Impulsivity
describes an individual's lack of planning and tendency to act before thinking a
situation through (Zuckerman, 2002). The trait of impulsivity has a heritability
factor, which consists of four possible components, namely: inhibitory control
(manifested in resistance to delayed gratification), decision time (being obsessive),
persistence in ongoing tasks and sensation-seeking (Buss & Plomin, 1984).
Eysenck and Eysenck (1977) investigated the personality trait of impulsiveness in
relation to the personality dimensions of extraversion, neuroticism and psychoticism.
They found that Impulsiveness consisted of risk taking behaviour, liveliness and non-
planning. Their results indicated that general impulsiveness correlated positively
with extraversion. Furthermore, more specific impulsive tendencies correlated
positively with neuroticism and psychoticism, suggesting that this trait is
pathological.
Barratt (1972) proposes a neuropsychological model with an inverse relationship
between impulsivity and anxiety. High impulsiveness is associated with sociopathic
32
behaviour when anxiety levels are low within the individual. Rauch, Savage, Alpert,
Fischman and Jenike (1997) found in their group of 23 right-handed adult outpatients
meeting criteria for obsessive-compulsive disorder (n = 8), simple phobia (n = 7) and
posttraumatic stress disorder (n = 8) that there are certain brain regions indicated by
positron emission tomography (PET) scans, which mediate symptoms across different
anxiety disorders. This finding would indicate a substantiation of a neurological
factor mediating core anxiety symptomatology.
Harburg, Gleibermann, Gershowitz, Ozgoren and Kulik (1982) investigated whether
there are certain blood markers (a method of ascertaining a genetic influence)
associated with measures of temperament. Their sample consisted of 400 males and
470 females. They used the Eysenck Extraversion-Introversion/Neuroticism
questionnaires and the Buss-Plomin Temperament questionnaires. They found that
the Lewis red blood cell phenotypes were significantly associated with Impulsivity
and Anger in males and this blood marker was also significantly associated with
Sensation-seeking (as a subscale of Impulsivity) for females. The findings implicate
the same blood marker being related to different temperament traits in males and
females. This possibly indicates that there could be separate blood markers
responsible for the sensation trait in males as this trait was found to be higher in
males by Rushton, Fulker, Neale, Nias and Eysenck (1986).
2.2.4.3 Neuroticism The temperament trait of neuroticism is characterised by a constant and long lasting
feeling of anxiety. This temperament trait has been previously discussed under
section 2.2.6.2 as one of the temperament traits proposed by Eysenck. The defining
criteria of this temperament trait have remained similar across theories. Anxiety as a
trait is related to sensitivity to signals of punishment and non-reward. The higher the
individual's level of sensitivity the higher the individual's level of anxiety (Strelau,
1998). Slessareva and Muraven (2004) found that sensitivity to punishment is
33
positively correlated with the trait of neuroticism. Neuroticism and anxiety describe
emotional upset (Zuckerman, 2000) and these traits have been found to correlate
negatively with sociability (Zuckerman, 1991). The genetic relationship between
anxiety and neuroticism has been supported by Carey and DiLalla (1994), with genes
accounting for over 50 percent of the correlation.
In the Larsen and Ketelaar (1991) study on personality and susceptibility to positive
and negative emotional states they propose two views on the interaction between
personality and the environment. The temperament view states that certain traits like
extraversion and neuroticism represent an endogenous susceptibility to positive and
negative affect. The instrumental view proposes that certain temperament dimensions
foster a creation of certain life events and that these lifestyle differences determine
levels of long-term positive or negative affect. Magnus, Diener, Fujita and Pavot
(1993) investigated the personality traits of extraversion and neuroticism as predictors
of objective life events. The sample consisted of 84 females and 46 males. Their
follow-up sample consisted of 62 women and 35 men. To measure personality they
used the NEO Personality Inventory and life change was measured by the Life Events
Checklist. They found that measures of extraversion and neuroticism remained stable
over a four-year period. Furthermore, their hypothesis was confirmed in that
extraversion predisposed the subjects to experience greater numbers of objective
positive events whereas neuroticism predisposed the subjects to the occurrence of
objective negative events. More specifically, Asendorpf and Wilpers (1998)
investigated the effects of personality on social relationships. Their sample consisted
of 173 females and 64 males that completed the German version of the Big Five
factors of personality (NEO-FFI, by Costa and McCrae), a Relationship
Questionnaire and a daily diary. The results indicated that personality influences
social relationships, but not vice versa. For example they found that extraversion
influenced the subject's number and quality of social relationships.
34
2.2.4.4 Aggression and Hostility
Aggression and hostility are linked to a person's verbally-aggressive, rude,
thoughtless or antisocial behaviour. These individuals might also be spiteful and
have a short temper (Zuckerman, 2001). The aggression trait has a genetic basis
(Dilalla & Jones, 2000) and according to Rothbart, Derryberry and Hershey (2000)
one can predict adult aggressive behaviour as early as 10 months of age by
researching irritability-frustration and early proneness to frustration in infants. The
hostility trait has some of the same characteristics as Eysenck’s psychoticism
temperament trait (Zuckerman, Kuhlman, Joireman, Teta & Kraft, 1993). Rushton,
Fulker, Neale, Nias and Eysenck (1986) investigated inter alia the heritability of
aggressiveness in twin pairs. The sample consisted of 206 monozygotic female twin
pairs, 90 monozygotic male twin pairs, 133 dizygotic female twin pairs, 46 dizygotic
male twin pairs and 98 opposite sex dizygotic twin pairs. They used the aggression
items from the Interpersonal Behaviour Survey to collect data regarding this
construct. The results indicated that approximately 50 percent of the twins' variance
in aggression was related to a genetic influence. Very few belligerent tendencies are
due to common shared environment. This study indicates that the genetic basis of
behaviour could aid in the understanding of human temperament. A study done by
Tellegen et al. (1988) using monozygotic and dizygotic twin pairs reared together and
reared apart confirms that 50 percent of personality diversity can be attributed to
genetic diversity.
Boddeker and Stemmler (2000) found that individuals who score high on neuroticism
tend to react with strong physiological and behavioural anger compared with
individuals who score low on neuroticism. Anger is also a reliable predictor of
delayed onset in PTSD (Ehlers, Richard & Bryant, 1998). Beckham, Calhoun, Glenn
and Barefoot (2002) maintain that hostility could lead to the development of PTSD
following exposure to trauma. In addition, they mention that there are gender
differences in the expression of hostility as men are more likely to foster hostile
35
attitudes and are more likely to exhibit verbally and physically aggressive behaviour
compared to women. However, Beckham, Calhoun, Glenn and Barefoot (2002) quote
research indicating that both men and women with PTSD have higher rates of
hostility and anger than their counterparts without PTSD. The above literature
indicates a possible relationship between the temperament trait of hostility and PTSD.
The next section describes the temperament traits of activity and sociability.
2.2.4.5 Activity and Sociability
According to Zuckerman (2000) activity is characterised by the individual's need to
stay engaged all the time. The trait describes the individual as becoming restless or
impatient when there is nothing to do. A high score on this trait is indicative of high
energy levels and a fondness of challenging situations and hard work (Zuckerman,
2002). This trait has also been associated with positive emotionality according to
Bates and Wachs (1994). Activity is seen to emerge as the balance between
serotonergic and catecholminergic systems (Zuckerman, 1991).
Sociability describes individuals who have a compulsion to be around others and they
are reinforced by social rewards and also engage in manners to obtain rewards. They
tend to get upset when deprived of social interaction and appraisal. Sociable people
prefer the company of others and also prefer to share activities with others. The
social individual enjoys having many friends and shows an intolerance for social
isolation (Zuckerman, 2002).
Zuckerman's temperament types are relevant to the current investigation as not only is
his temperament questionnaire used, but he also describes temperament types, which
could be helpful in identifying various temperament profiles and how these
temperament types react in certain situations. The next section explicates resilience,
described by Antonovsky as sense of coherence.
36
2.2.5 Antonovsky's Sense of Coherence
Aaron Antonovsky introduced the concept of 'Salutogenesis' which is derived from
the Latin word, 'salus' which means health and the Greek word 'genesis' which means
origin. 'Salutogenesis' refers to the study of the origins of health (Antonovsky, 1994).
This line of thinking was motivated by Antonovsky's observation that most health
studies focussed on a pathogenic view and excluded factors that were causing some
individuals to stay healthy even when confronted by destructive demands (Ortlepp &
Friedmann, 2001). Antonovsky (1987) posed a salutogenic question concerning the
manner in which individuals cope with stressors. Antonovsky maintained that
individuals with a strong sense of coherence are able to deal effectively with stressful
situations, whereas individuals who have a weak sense of coherence find it
challenging to manage stressful encounters (Antonovsky & Sagy, 2001; Strumpfer &
Wissing, 1998; Vollrath, 2001). This section aims to describe the sense of coherence
construct and its relation to stressful life events.
2.2.5.1 The sense of coherence concept
When individuals are exposed to certain stressful situations, there is a possibility that
a range of undesirable effects might manifest. There is also the possibility that an
individual will cope adequately with the demands of the same situation (Ortlepp &
Friedman, 2001). This question of how and why individuals respond in certain ways
to stressful situations, gave rise to various models of resilience. Resilience is defined
as patterns of psychological activity which enable a person to be strong when faced
with extreme demands. Resilience is also classified as psychological adaptation,
which varies from situation to situation. An extremely demanding situation will
arouse appropriately strong resilience and, after the individual has dealt with the
challenging situation, a phase of relaxation occurs (Strumpfer, 2001).
37
Antonovsky developed the construct 'sense of coherence' as a resilience construct.
This is a temperament trait defined as a: "global orientation that expresses the extent
to which one has a pervasive, enduring though dynamic feeling of confidence that the
stimuli deriving from one's internal and external environments in the course of living
are structured, predictable and explicable" (Antonovsky, 1987, p.19). Antonovsky
predicted that sense of coherence is not only stable over time but also similar across
cultures. Individuals across various cultures attain similar levels of sense of
coherence, despite socio-economic differences (Bowman, 1996). This global
perceptual disposition is thought to underlie specific coping strategies. The
formulation of sense of coherence is dependent on the availability of 'generalised
resistance resources' (GRR) (Mlonzi & Strumpfer, 1998; Rennemark & Hagberg,
1997). A strong sense of coherence will enable an individual to activate and use
GRR's to combat stressors, which then in turn strengthen the person's sense of
coherence via a feedback loop (Levenstein, 1994). A person with a low sense of
coherence is not able to activate the available resources and thus the consequence is
health breakdown (Ortlepp & Friedman, 2001). Sense of coherence is expected to be
a stable trait during adulthood with only temporary fluctuations when serious events
occur (Languis, 2001).
The sense of coherence concept has been shown to correlate positively with internal
locus of control (Antonovsky, 1992), self-esteem, hardiness and mastery but
negatively with perceived stress, psychosomatic complaints, anxiety, neuroticism and
depression (Antonovsky, 1987; Rennemark & Hagber, 1997). Kobasa (1979)
investigated the relationship between stressful life events, personality and health. A
group (n=86) who experienced high levels of stress and who did not fall ill was
compared with a group (n=75) of individuals who reported falling ill directly after
their stressful encounter. The results indicated that the group who experienced high
stress, but low illness were more vigorous towards their environment, had a higher
sense of meaningfulness, hardiness and locus of control when compared with the
other group. Beasley, Thompson and Davidson (2003) support Kobasa (1979) in
38
their study on resilience in response to life stress. Their sample consisted of a group
of university students (n=187) who completed measures of life events and traumatic
experiences, cognitive hardiness, coping style, general health, somatization, anxiety
and depression. The results indicated that cognitive hardiness, coping style and
negative life events directly impacted on measures of psychological and somatic
distress. Matthews, Scheier, Brunson and Carducci (1989) found that unpredictable
stressful events could lead to somatic complaints compared to predictable events.
The sense of coherence concept is composed of three factors, namely:
comprehensibility, manageability and meaningfulness (Antonovsky, 1983; Zika &
Chamberlain, 1988). Comprehensibility concerns the extent to which stimuli are
perceived as cognitively understandable. The individual's sense of comprehension of
life events is constantly influenced by both cognitive and emotional considerations.
Manageability refers to the individual's perception of available resources. This will
enable the individual to master the demands of the current situation and not feel
traumatised or stressed. This construct includes the individual's belief in whether the
situation or stressor can be managed in a way that is endurable. Meaningfulness is
the motivational component of the sense of coherence concept. To have a strong
sense of meaningfulness means that the individual views any life area as important
and worth engaging in. An individual with a strong sense of meaningfulness looks at
problems as challenges more than misfortunes (Antonovsky, 1983). Vollrath (2001)
states that a low sense of coherence loads heavily on neuroticism, which could
explain its relation to the stress process.
Strelau and Zawadzki (2003) investigated whether temperament and coping styles
would predict PTSD in a sample of individuals who had experienced a disaster. The
researchers had three samples of flood victims (n=997) and measured PTSD at three
different time periods relating the results to temperament, coping styles and trauma
severity. They found that an emotional style of coping is significantly related to the
development of PTSD symptomatology. They also found that temperament traits are
39
consistently related to PTSD symptoms. However, they concluded that traumatic
severity and emotional reactivity are the most reliable predictors of PTSD. The next
section explicates the relationship between sense of coherence and life stressors.
2.2.5.2 Sense of coherence and stress
Sense of coherence determines the manner in which a person deals with the
experience of trauma and stress (Ortlepp & Friedman, 2001). A high sense of
coherence correlates significantly with life satisfaction. An individual with a high
sense of coherence is more satisfied with life and is therefore more positive, whereas
a person with a weak sense of coherence finds it difficult to make sense out of life
stressors (Rani, 1998). Flannery and Flannery (1990) found that sense of coherence
correlates negatively with life stress and symptoms related to the impact of life stress.
Ortlepp and Friedman (2001) found in their study of non-professional trauma
counsellors (n=130) that sense of coherence, particularly the sub-components of
manageability and meaningfulness, emerges as having statistically strong main
effects on the indicators of traumatic stress. According to Snekkevik, Anke, Stanghell
and Fugl-Meyer (2003) a weak sense of coherence is correlated with high
psychological distress, anxiety and depression, and is stable over time after severe
multiple trauma. Sense of coherence enables an individual to develop a more active
and adaptive style when dealing with stress (Bowman, 1996).
According to Gibson and Cook (1996) low sense of coherence has been related to the
trait of neuroticism. As indicated before, neuroticism is linked to the autonomic
system and is involved in somatic expression of emotional states through the
sympathetic branch. Prolonged arousal of this area could lead to health and
emotional problems. They found in their study using a group of 95 students, that
neuroticism has a highly negative relationship with sense of coherence. Neuroticism,
in turn, has been related to exaggerated reports of somatic complaints. Zatzick (2003)
found that victims of trauma who show signs of depression and PTSD after their
40
trauma are likely to indicate somatic complaints a year later. This study indicated a
relationship between sense of coherence and temperament traits. Hart, Hittner and
Paras (1991) found that sense of coherence is negatively correlated with trait anxiety.
Thus there exists a difference between the temperament profile of individuals who are
able to deal with stressors and those who are unable to deal with the demands and
pressures of the world (Viviers, 1998).
Sense of coherence plays an important role in individual response to stressful
situations and has therefore been included in the current investigation. The next
section explicates the relationship between individual temperament and stressors
(Geyer, 1997).
2.3 TEMPERAMENT AND STRESS The functional significance of temperament can be understood when an individual is
confronted with a situational demand (Strelau, 2001). The study of the relationship
between temperament and stress has been increasing in popularity amongst
researchers (Gunnar, 1994). One such researcher is Richard Lazarus (1971) who
proposed a transactional stress theory. This theory states that temperament not only
affects the appraisal of and coping with stress, but it is also important with regard to
the selection and shaping of stressful situations (Vollrath, 2001). Appraisals are the
individual's evaluation of available resources to cope with a stressful event. If
adequate coping resources are present, it will reduce the stress response even if the
threat is severe (Gunnar, 1994). This section aims to clarify what is meant by the
term stress and related concepts. An explication of the temperament – stress
relationship will be presented, followed by an investigation of stress and coping.
41
2.3.1 Describing stress
Psychological stress can be conceptualised as states of anxiety, fear and anger, which
occur when certain physiological and biochemical changes exceed the baseline level
of arousal (Stelau, 1998). Stress occurs when an individual is unable to deal
effectively with the requirements of the environment (Velamoor & Mendonca, 2003).
Furthermore, the intensity of stress is the degree of difference between the demand of
the stressful situation and the individual's capacity to deal with the stress. One of the
demands that an individual could be confronted with is an unpredictable and
uncontrollable life event. This stressful life event is characterised by the individual’s
inability to anticipate the event happening (Strelau, 1998). According to Strelau
(1998) when the individual experiences a stressful life event, he or she is faced with
certain demands. There are two types of demands an individual could confront,
namely: objective and subjective demands. Objective demands are stressful
situations that are beyond the control of the individual such as trauma, war, death and
disaster. Subjective demands are understood to be the individual's interpretation of
the event, for example the amount of threat or harm the individual perceives. The
amygdala is responsible in part for the generation of subjective emotional experience.
This part of the limbic system formulates and makes attributions about the emotional
significance of some stimulus or event (Nelson, 1994).
Many psychological (such as anxiety and depression), physiological or biochemical
(such as psychosomatic diseases) changes can occur within the individual as a
consequence of chronic or excessive stress (Barlow & Durand, 1999). Excessive
stress is defined as extremely strong negative affects that the individual experiences,
accompanied by very high levels of arousal determined by physiological responses
through the amygdala, cortex etc (Strelau, 1998). Chronic stress is that state of stress,
which might not be excessive but rather occurs frequently. Furthermore, not all states
of chronic or excessive stress will lead to negative consequences as there are multiple
variables that need to be taken into consideration (Strelau, 1998). The individual's
42
ability to deal constructively with the demands of stressful situations depends on
various factors like: intelligence, special abilities, skills, personality and temperament
traits, experience with stress-inducing situations, coping strategies and the current
physical and psychological state of the individual (Gunnar, 1994).
2.3.2 The temperament – stress relationship
Pavlov was one of the first researchers who demonstrated individual differences in
temperament, when faced with an extremely stressful situation. There was an
unexpected flood in his laboratory after which he observed that behaviour disorders
occurred in dogs classified as having weak nervous systems, whereas dogs with
strong nervous systems, dealt with the excessive stressful event without developing
disturbances in behaviour (Strelau, 2001). Ormel and Schaufeli (1991) support
Pavlov’s understanding, as they found that stress symptom levels depend primarily on
temperament factors.
According to Strelau (1998) there are three ways in which temperament can influence
the effects a certain stress phenomenon has on an individual. Firstly, the stimulus
value of the stressful situation has an impact on the manner in which an individual
will respond. Secondly, the individual’s normal baseline level of arousal will have a
contribution as people who tend to be generally anxious are most likely to respond
with intense anxiety in stressful situations. Lastly, temperament traits associated with
emotionality and the tendencies to generate negative emotions could make an
individual vulnerable to severe stress reactions (Strelau, 1998). Specific temperament
traits have been linked to the manner in which people react when confronted by a
stressful situation.
Temperament traits that are associated with low arousability, like extraversion, high
sensation-seeking or strong type of nervous system will cause an increase in stress
levels when interaction occurs with life events characterised as demands of low
43
stimulative value, such as isolation. However, temperament traits characterised by
high arousability, such as introversion, neuroticism, low sensation-seeking, or weak
type of nervous system, will procure high levels of stress when an interaction with
events of high stimulative value, like death and traumatic stressors, occur. Thus,
temperament acts as a moderator of stress (Strelau, 2001). This has been empirically
investigated by Gunnar (1994) who found that shy children reduce the likelihood of
threatening encounters through playing more by themselves, whereas assertive,
outgoing children increase the risk of such encounters by seeking interactions with
unfamiliar peers.
2.3.3 Stress and coping
Lazarus (1971) proposed a transactional perspective of coping with stress. Coping is
understood as a transaction between the individual and the environment with an
emphasis on process. Transactional stress theory proposes two types of coping,
namely emotion-focused coping and problem-focused coping. Emotion-focused
coping refers to the individual's effort to deal with his/her emotional responses to a
stressor. Problem-focused coping methods are the strategies implemented by the
individual to deal directly with the stressors (Suls, David & Harvey, 1996). The
transactional stress theory proposes a process described as a) the individual
experiencing a stressful life event; b) the individual evaluating the situation (primary
appraisal) as well as the available resources for coping (secondary appraisal); c) the
individual implementing coping strategies; and d) reaching some outcome (Gunthert,
Cohen & Armeli, 1999).
When describing coping strategies in terms of temperament traits, one will find that
traits such as extraversion, sensation-seeking or strength of the nervous system
(Bates, 1989) will activate problem-focussed coping. Emotion-oriented temperament
traits like inhibited temperament, neuroticism and emotionality will activate an
emotion-focussed coping style (Vollrath, 2001). Bolger and Schilling (1991)
44
investigated the role of neuroticism in experiencing distress in daily life. Their
sample consisted of 339 individuals who wrote daily reports on minor stressful events
and associated mood for a period of six weeks. The results suggested that an
individual's reaction in a stressful situation is twice as important as the actual stressor
when explicating the relationship between neuroticism and daily life stressors.
Bolger and Zuckerman (1995) used this relationship between neuroticism and
stressful daily events to indicate personality differences in reactivity. They stated that
these differences are due to differential choice of coping and the effectiveness of the
coping. Gunthert, Cohen and Armeli (1999) found that high neuroticism individuals,
compared with low neuroticism individuals, use less adaptive coping strategies.
Therefore, whereas neurotics indicate a suppressed style of coping, extraverts utilise
direct coping strategies. These direct coping strategies of extraverts were found by
Amirkhan, Risinger and Swickert (1995) to be social support seeking and optimism.
Extraverts are thus more likely to utilise their social relationships as a buffer variable
when confronted with stressors than introverts. This style of coping also stems from
the optimistic behaviour in extraverts. Thus, emotion-oriented temperaments utilise
emotion-oriented coping styles, whereas problem-oriented coping is related to action-
oriented temperament traits (Strelau, 1998). Temperament will, therefore, determine
individual coping strategies (Vollrath & Torgersen, 2000).
Bolger and Eckenrode (1991) found that social contacts buffer against anxiety, but
perceived support does not. Thus, it is important to distinguish between perceived
social support and actual social support when identifying buffer variables in stressful
situations. Perceived social support could be determined by different temperament
types (Kitamura et al., 2002). According to Holmes, William and Haines (2001)
individuals are able to deal with stressful events better if they have a high level of
resilience.
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2.4 TEMPERAMENT AND PERSONALITY DISORDER
It has previously been stated that temperament has a substantial impact on the manner
in which an individual reacts to (a) stressful situation(s). Furthermore, temperament
could also determine the level of psychological impact a stressor has on the
individual. Research has suggested a great deal comorbidity between certain
personality disorders and PTSD in individuals who have experienced trauma in their
childhood or as adults. Spiegel and Cardena (1991) state that apart from possibly
developing a personality disorder(s) after a traumatic event, other consequences are
fear, anxiety, intrusiveness, depression, self-esteem disturbances, anger, guilt, shame,
dissociation, hyperarousal and somatic disturbances. This section aims to discuss the
relationship between temperament, PTSD and the development of personality
disorders.
Trull (1992) investigated the relationship between certain temperament dimensions
and personality disorders. To measure temperament the NEO-PI was used and the
clinical measure called the Millon Clinical Multiaxial Inventory-II (MCMI-II). In
addition to self-report instruments, a semi-structured interview, the Structured
Interview for DSM-III-R Personality Revised, was conducted with each subject and
assessed the presence of personality disorders. The sample consisted of 54
psychiatric outpatients. The results indicated that neuroticism which is composed of
facets such as anxiety, hostility, depression, self-consciousness, impulsiveness and
vulnerability provide a good description of borderline personality disorder, especially
the characteristics of hostility, impulsiveness and depression. Furthermore, the
temperament trait of neuroticism was not only found characteristic of borderline
personality disorder, but also obsessive-compulsive personality disorder and
dependent personality disorder. Significant positive correlations with neuroticism
were also found across measures for paranoid personality disorder, schizotypal
personality disorder, histrionic personality disorder, narcissistic personality disorder,
avoidant personality disorder and passive-aggressive personality disorder. This study
46
indicates that the temperament trait of neuroticism could act as a vulnerability factor
in the development of certain personality disorders. Shortcomings of the study were
the inconsistency of the sample as gender, race or outpatient as well as inpatient
treatment were not controlled for. Furthermore, life events were not assessed and
thus no definite conclusion can be drawn from the study.
Golier et al (2003) found in their study that subjects with borderline personality
disorder were twice as likely to develop PTSD than subjects without borderline
personality disorder. Zanarini et al. (1998) found a high frequency of PTSD in
people with borderline personality disorder and, according to Gunderson and Sabo
(1993), this could be due to a symptom overlap. Borderline personality disorder is
characterised by impulsiveness, self-hate, suicidal ideation and instability.
Individuals who meet the criteria for this disorder are usually very intense and
fluctuate rapidly from anger to depression (Barlow & Durand, 1999). Although
stating that no clear model exists to explain the co-occurrence of borderline
personality disorder and PTSD, childhood abuse and adult trauma are common
precursors. However, in the Golier et al. (2003) study they found that links with
trauma and PTSD were not unique to borderline personality disorder, as paranoid
personality disorder indicated even higher rates of PTSD than subjects with
borderline personality disorder. Paranoid personality disorder is characterised by a
general state of mistrustfulness, difficulty making friends and suspiciousness (Barlow
& Durand, 1999). Their study indicated that trauma often precedes the development
of borderline personality disorder. The question, however, is whether the
comorbidity of a personality disorder and PTSD increases psychological dysfunction.
Zlotnick, Franklin and Zimmerman (2002) investigated whether patients with
comorbid borderline personality disorder and PTSD have a more severe clinical
profile than patients with only one of these disorders. Their subjects consisted of
borderline personality disorder without PTSD (n=101), PTSD without borderline
personality disorder (n=121), comorbid borderline personality disorder and PTSD
47
(n=48), and major depression without PTSD or borderline personality disorder
(n=469). The subjects were assessed with a structured interview for psychiatric
disorders, which consisted of the Structured Clinical Interview for DSM-IV and the
Structured Interview for DSM-IV Personality. The result showed no significant
difference between patients with comorbid PTSD and borderline personality disorder,
compared with those with PTSD and no borderline personality disorder. However,
patients with borderline personality disorder and PTSD reported a greater number of
PTSD symptoms and avoidant symptoms than PTSD patients without borderline
personality disorder. Thus, there seems to be a slight difference when comparing the
two groups. The study has value in that it explicates the intricate nature of
comorbidity between PTSD and borderline personality disorder. It also suggests that
associated features of PTSD may not include borderline traits, as previously
postulated by Herman and Van der Kolk (1987) and Hodges (2003) who stated that
borderline personality disorder might be a complex variant of PTSD as seen in
features such as affective instability, anger, dissociative symptoms and impulsivity.
Although Hodges (2003) suggests that women who suffer from borderline personality
disorder after trauma should rather be diagnosed with PTSD, Grossman et al. (2003)
indicated that a dexamethasone suppression test (medication which has an effect on
the Central Nervous System (CNS)) shows a high level of cortisol suppression
associated with PTSD in subjects with personality disorder, as well as in subjects
without personality disorder. This indicates that separate diagnoses for PTSD and
borderline personality disorder might be necessary. Age at which trauma occurred
and a borderline personality disorder diagnosis has no significant impact or
interaction effects on cortisol suppression. As early as the eighties the question was
asked if stress disorders are merely a variant of other personality disorders (Kolb,
1987).
Somatisation has also been associated with severe traumatic experiences.
Somasundaram and Sivayokan (1994) found in their civilian population who had
experienced war trauma, that somatisation was present in 41% of the population
48
compared with 27% who indicated PTSD, 25% who showed depression, 19%
hostility and 26% another anxiety disorder. Yaari, Eisenberg, Adler and Birkhan
(1999) found that Holocaust survivors who experienced intense trauma, report higher
pain levels, more pain sites and higher levels of depression. This illustrates a somatic
component related to the post-trauma experience. In another study, Stein et al.
(2004) found that women who experienced trauma in the form of sexual assault had
increased somatization scores, and physical complaints across multiple symptom
domains, as well as health anxiety. This study confirms a strong association between
trauma exposure and somatic symptoms. Van der Kolk et al. (1996) state that
somatisation is a manner in which individuals cope with a traumatic experience.
Somatic complaints such as headaches and stomach problems have been found in 59
percent of journalists who report on traumatic stories (Simpson & Boggs, 1999). It is
therefore clear that exposure to trauma and consequent PTSD could be related to a
personality disorder characterised by somatic complaints.
This section illustrates the complexity of diagnosing post trauma personality disorder
and PTSD. The question remains whether a personality disorder will predispose an
individual to develop PTSD after exposure to a traumatic event or whether a
traumatic event will predispose an individual to develop a personality disorder and
PTSD. In the event of an individual being diagnosed with both a personality disorder
and PTSD after having experienced a traumatic event, the question remains as to
whether the individual should receive two diagnoses or one. Lastly, symptomatic
experiences of many personality disorders seem to overlap with symptoms of PTSD
leading to difficulty in making a distinct diagnosis and determining a cause-effect
relationship.
2.5 CHAPTER SUMMARY
The chapter aimed at identifying clear differences between personality and
temperament. Temperament was described as being the biological bases of
49
personality, which is modifiable through the course of socialisation and life
experience. However, it was argued that temperament dimensions form the stable
aspect of personality. Thereafter, the theories of Eysenck, Gray, Zuckerman and
Antonovsky were discussed in support of the biological bases of temperament. The
various temperament types proposed by these theorists were described. Antonovsky's
sense of coherence was argued to be a stable temperament trait, which has an impact
on the manner in which an individual responds to life stressors.
An important relationship between temperament and stress was identified and
explicated. Certain temperament traits were recognised as having a possible strong
impact on the manner in which an individual will respond to traumatic or stressful
situations. The literature also suggests that temperament not only has an important
impact on an individual's response to stressful encounters, but could also act as a
vulnerability for the subsequent development of stress or personality disorders. The
chapter concluded by briefly mentioning the complexity of determining whether a
traumatic situation will have an impact on a persons personality functioning or
whether a person's personality functioning will impact on the manner in which the
individual deals with traumatic or stressful situations. The next chapter will describe
Posttraumatic Stress Disorder and its relationship with personality.
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