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Chapter 2: Literature
Review
In this chapter, focus is on
various relevant literatures that explain the concept of personality
traits as well as the use of personality questionnaires.
Personality Traits
One of the pioneering trait
psychologists, Gordon Allport (1937), saw traits as organised mental
structures, varying from person to person, which initiate and guide
behaviour. There are two important qualifications to this general
principle. First, as Hettema and Deary (1993) pointed out, the explaining
of behaviour requires different levels of analysis, including genetics,
physiology, learning and social factors. Allport's notion that all the
various manifestations of traits can be explained at a single level of
'mental structure' is simplistic. Hence, causal models of trait action
will vary depending on the level investigated, although the ultimate
research aim is to develop a trait theory that will connect various
levels. Second, the causal effects of traits on behaviour may be indirect.
Traits interact with situational factors to produce transient internal
conditions or states, which may sometimes be a more direct influence on
behaviour than the trait. For example, trait anxiety may interact with an
immediate situational threat to generate transient state anxiety, which in
turn disrupts ongoing information processing and impairs performance (Spielberger,
1966).
Tendency to experience
negative emotions are assumed by some to relate to some fundamental, core
quality of the person, which might be influenced substantially by genetic
factors (Eysenck, 1967; McCrae et al., 2000). Again, even within theories
that are sympathetic to the traditional view of traits, there has been
some modification of the basic view. For example, Cattell and Kline (1977)
distinguished 'surface' traits, which are simply clusters of overt
responses which tend to be associated, from 'source' traits, which are
deeper properties of the person with causal effects on behaviour. Modern
developments of traditional theory seek to identify and explain underlying
sources of consistency in behaviour, whether these are conceived of as
genetic, physiological or cognitive in nature. The process of relating
operationally defined measures such as questionnaire scores to theory is
often referred to as construct validation.
Both assumptions of
traditional trait theory—their causal primacy and inner locus—have been
challenged more radically. The alternative to causal primacy is the view
that traits are a construction with no independent causal status. For
example, Buss and Craik (1983) argued that traits are simply descriptions
of natural categories of acts. Wright and Mischel (1987) characterised
traits as conditional statements of situation—behaviour contingencies.
Furthermore, traits may be jointly constructed by two or more people in
social interaction, according to the social dynamics of the situation (Hampson,
1988). Social psychological approaches to traits tend also to abandon the
inner locus assumption. Even if traits represent genuine psychological
structures, these structures may be no more than the superficial mask the
person presents to the outside world, in order to present a socially
acceptable self-image to other people.
The upshot of these
considerations is that there is no generally accepted scientific theory of
traits. Some trait theorists have tended to take the relatively easy
option of focusing on the dimensional structure and measurement of traits
rather than investigating their underlying nature (Goldberg, 1993).
However, it should be clear from the preceding discussion that trait
descriptions cannot be accepted at face value, and that there may be
various qualitatively different types of explanation for consistencies in
self-reports and behaviours. In recent years, progress has been made in
developing psychobiological information processing and social
psychological trait theories, which are partly complementary and partly
competing accounts.
Personality Questionnaire:
Development and Quality Factors
Contemporary views of traits are
intimately related to the processes of measurement and assessment
necessary to identify basic personality dimensions. Typically, the trait
researcher has some hypothesis about the number and nature of the
principal dimensions, and designs a questionnaire to measure them.
Subsequent work investigates how useful a measuring device the
questionnaire actually is, and modifies the questionnaire items in
response to any shortcomings detected.
The initial development of a satisfactory
questionnaire for measuring traits is not easy. Care must be taken in the
composition of items: they must be easily understood and unambiguous,
applicable to all respondents, and unlikely to cause offence (Angleitner &
Wiggins, 1986). There should also be some systematic sampling of the
various expressions of the personality trait of interest. It is important
also to check that items are not strongly contaminated by response sets or
biases, such as social desirability, yea-saying or extreme responding. It
is also necessary to assess its adequacy formally, by application of
psychometrics, the science of psychological measurement. Psychometrics
provides statistical techniques which determine the ability level of a
particular questionnaire as a measuring tool. The sophistication of modern
techniques and the number-crunching power afforded by computers provide
the contemporary researcher with powers of data analysis far beyond those
envisaged by the pioneering trait researchers.
In order to ensure the efficacy of a
personality questionnaire, several factors must be considered. One of
which is its reliability. This refers to the accuracy with which the
questionnaire measures a given quality. Reliability may be assessed by
administering two alternative measures of the trait to a sample of
subjects and computing the correlation between them. If the correlation is
high, the quality can be assessed consistently and the scale is reliable
or internally consistent. Otherwise, if the two supposedly equivalent
forms are not assessing the same quality, the scale is unreliable and the
items must be revised. The Cronbach alpha statistic is a widely used
measure of reliability calculated from a single set of test items. It is,
in effect, the correlation of the test with itself. In general, alpha
tends to increase both as inter-item correlation increases, and as the
number of items on the test increases (Henson, 2001).
Another important factor to consider in
personality questionnaires is their stability. Reliability should be
distinguished from stability, which is the test— retest correlation of the
scale over a given time interval. Personality is expected to change slowly
as the person grows older, but it is expected that stabilities of trait
measures will be fairly high over periods of a year or more. If the
assessor has a scale that is reliable but has a low test—retest
correlation, the assessor may be evaluating a mood or some other transient
quality of the person, rather than a genuine trait (Neville et al., 2001).
The third essential factor for a
personality questionnaire is validity, which pertains to the tool’s
ability to assess what it purports to assess. A scale may be reliable but
not valid. For example, a fortune teller might use a highly consistent
method for inferring a person's future from the lines on their palm, but
the consistency of the technique would be no guarantee that the fortune
teller's predictions were accurate. The most straightforward and
convincing method for assessing validity is referred to as criterion or
predictive validity. The trait measure is correlated with some independent
index of a quality associated with the trait. Other external criteria
frequently used in personality research include measures of job
performance and behaviour, psychophysiological functioning and clinical
abnormality (Bartram, 1995). Establishing predictive validity is indeed
important. The essence of integrating validity is that correlations
between the trait and external criteria are predicted in advance from an
adequate scientific theory, rather than from common sense or a superficial
analysis of trait characteristics. For example, the psychobiological
theory of personality can be used to predict how a particular trait should
correlate with measures of autonomic functioning, such as heart rate.
Another form of validity is called
construct validity. This arises out of the total web of empirical data and
theoretical analysis, which builds up around a trait, sometimes referred
to as its nomological network (Eysenck, 1981). The difficulties of
construct validity are those of establishing scientific truth. Even 'good'
theories are never fully satisfactory, and require periodic modification
of hypotheses and concepts as new research findings are obtained (Lakatos,
1976). Hence, construct validity is always somewhat provisional, and may
be reduced or enhanced by fresh research.
Personality Questionnaire:
Empirical Studies
There had been a number of studies related
to personality questionnaires and its ability to detect various personal
attributes. In one research, Epstein (1977) asked subjects to rate and
describe their positive and negative emotions, impulses, behaviour and
situations for over two weeks. Although the correlation between single
days was as low as suggested by the work of Mischel (1968) and Bem (1972)
suggested, the reliability of measures in each of these categories ranged
from 0.40 to 0.88, with a median of 0.72 when odd and even days were
correlated for data collected for between twenty-four and thirty-four
days. Another message of this study was that, in all of the above
categories, a certain minimum frequency of occurrence and variance was
required to achieve high reliability, whether it was between behaviour and
emotions. Epstein reckoned that, given the frequent assertion that there
is a 0.30 barrier for cross-situational reliability coefficients, the
findings of this study are no less than dramatic.
Personality, behaviour, and even
situations as scored by judges independent of the subjects, were all
highly reliable when aggregated over several days; the low predictive
validity coefficients claimed by the situationists for personality
variables were imposed by error of measurement as the result of single
observations. Therefore, the procedure that others have employed all but
guarantees reliability coefficients to be low. It may be concluded that
those who have argued that personality is unstable have simply not used
procedures that can establish its stability. As Eysenck (1981) pointed
out, aggregation of data actually provides quite good evidence for
cross-situational consistency in studies such as that of Hartshorne and
May (1928) which purport to show situation specificity of behaviour.
Similarly, when personality is assessed through judges' ratings, large
numbers of behavioural observations may be needed for the behavioural
consistency and predictive validity of traits to appear (Moskowitz &
Schwartz, 1982).
Moskowitz (1988) studied the reliability
of ratings and behaviour counts of friendliness and dominance in
forty-three subjects who visited a laboratory on six occasions in order to
conduct a problem-solving exercise with one partner. Correlating ratings
(inferred traits) of friendliness and dominance made in one situation with
only one other situation gave coefficients of 0.26 and 0.12, respectively;
both were non-significant, but of the order expected from the criticisms
of Mischel. The same analyses performed on behaviour counts gave
coefficients of 0.37 (p < 0.05) for friendliness and 0.06 for dominance.
However, when generalisability (using coefficient alpha) was calculated
using the six situations the ratings values for friendliness and dominance
were 0.68 (p < 0.001) and 0.44 (p < 0.01), respectively. The value for
behaviour counts for friendliness was 0.78 (p < 0.001) and for dominance,
0.28 (ns). She concluded that there were high levels of cross-situational
generality for behaviour count and ratings measures of friendliness
(aggregated over six laboratory situations), and moderate levels of
generality for ratings of dominance.
Further, using data from only five
situations to predict friendliness ratings or behaviour counts in a single
situation, multiple R values of 0.50 and 0.57 were obtained for ratings
and behaviour counts, respectively (both p < 0.01). For dominance, the
expression of relevant behaviour was affected by whether the subject knew
the partner they were with in the situation. The use of abstract qualities
such as friendliness also seems to raise behavioural consistency. Funder
and Colvin (1991) showed cross-situational consistencies typically of
0.4–0.6 for behaviour coded by meaning, but substantially smaller
consistencies for specific instances of behaviour. For example, 'humour'
is more consistent than 'joke-telling'.
Other later works on personality tests
made use of trait constructs to predict behaviours with remarkable
success. Researchers used behavioural dispositions in a particular way—one
that takes the context into account and may be seen as a form of
interactionism (Wright & Mischel, 1987). As an alternative to theories
that see traits as causal agents or as mere summaries of observed
behaviours (e.g. Buss & Craik, 1983), Mischel sees a trait statement as
the 'conditional probability of a category of behaviours in a category of
contexts'. It is hard to imagine any trait theorist taking exception to
this definition, and the present authors consider it to be a good,
mainstream definition of a trait, stripped of beliefs about the origin of
the trait. In particular, the point that traits most reliably express
themselves in situations that are suited to their expression is accepted
by most, if not all, personality trait theorists. That is, it is difficult
to express extraversion whilst marching with other soldiers in a parade,
but much easier to express it at a party. What is remarkable about Mischel
and colleagues' research is the care with which it is formulated and
executed, and the high level of predictive validity that it provides for
personality traits from this once champion of situationism.
In a study, Wright and Mischel (1987)
asked raters to assess children on the traits of 'aggression' and
'withdrawal'. Several different observers watched the children's actual
behaviours over a period of time. The raters were also asked to judge how
demanding the situation was for the child, in comparison to the child's
competence. The hypotheses were complex: that children with high levels of
a trait would show more behaviours that were central to that trait
(feature-centrality), and that correlations between traits and behaviours
would be especially high if the situation was a demanding one for the
child. Feature-centrality needs explanation: with regard to aggression,
one 'feature-central' behaviour would be a threat issued to another child.
The feature-central threatening behaviour would be expected to show higher
correlations with aggression than would a non-feature-central trait such
as distractibility.
As hypothesised, children with given
levels of a trait showed more trait-relevant behaviours. The correlations
are especially strong when the demand level of the situation is high, and
when the rated behaviour is central to the trait concept, although
correlations are substantial for feature-central behaviours even in
low-demand situations. Ratings of traits made by others do predict
objectively observed behaviours. Wright and Mischel's study is a success
for trait theory, situationism and interactionism all at once: traits were
highly predictive of behaviours, the relevance of the situation made a
difference to the behavioural scores, and there was also a significant
trait—situation interaction. Thus, highly aggressive children displayed
more overall feature-central behaviours such as pushing and shoving, which
further increased as the demands of the situation rose.
This model of interactionism has continued
to develop, and Mischel and colleagues have conceptualised personality as
a dynamical system (Mischel and Shoda, 1995; Shoda, LeeTiernan, & Mischel,
2002). The authors' Cognitive Affective Personality System (CAPS)
describes affects, goals, expectancies, beliefs, competencies, and
self-regulatory plans and strategies as the basic units of personality.
The outcome of these interacting units is typically of an if…then…
form: e.g., if you encounter someone you know, then behave
in a friendly manner. The individual's repertoire of if—then connections
provides a unique behavioural signature or profile for that person.
Typically, these outcomes are then highly contextually dependent: e.g.,
showing friendly behaviour towards acquaintances, but not to strangers or
work colleagues. Nevertheless, the model assumes some personality
stability that produces consistency in how the individual behaves in
specific situations. As with trait models, it assumes personality develops
from both biological and cognitive-social influences, a point to be
elaborated in subsequent chapters.
Mendoza-Denton and associates (2001)
studied person by situation interactions by asking subjects to describe
themselves in 'if—then' terms ('I am…. when….') after they had performed a
task for which they were given either positive or negative feedback. In
doing so, the subjects were less likely to put themselves on extreme ends
of dimensions (as they might using standard personality inventories), and
less likely to misattribute—or overgeneralise—success or failure to
themselves, rather than to the specific situation. In addition, the
'if—then' framework also reduced the likelihood that subjects would
attribute reasons for others' behaviour to stereotypes. This 'dynamical
system' has also been modeled using computer simulations of in the same
terms, this idea is borne out in applied fields of research, too. For
example, while behaviours in certain crime situations are
consistent across individuals, people's traits alone do not predict
criminal involvement (Alison et al., 2002). Other studies have also shown
that 'driver stress' is predicted from situational factors such as traffic
congestion and time pressure of the journey (Hennessy, Wiesenthal & Kohn,
2000), together with dispositional stress vulnerabilities that are
specific to driving (Matthews, 2002).
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