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

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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

12

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

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(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

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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

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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

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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

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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

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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

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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)

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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

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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

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(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

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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

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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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