Personality psychologists are concerned with the consistent patterns of thoughts, feelings and behaviours that differentiate people from each other. Personality traits form the conceptual bedrock of personality psychology. Without traits, people would be inconsistent and unpredictable. We would have no means of deciding whom to choose as our best friends, work alliances or business leaders because people would be behaving randomly. Some differential psychologists also call themselves trait theorists. Adopting the position of a trait theorist usually goes beyond the assumption that people have enduring dispositions that predict their behavioural patterns. It also assumes that there are a limited and small set of core traits that can be measured using psychometric methods involving the construction and validation of questionnaires and personality tests. The continuing appeal of this approach is threefold; first, it has generated a wealth of research; second, it has expanded our conceptualisation about the personality characteristics that describe people throughout the world; third, it enables quantifiable measurement of personality traits that can be used to predict various important facets of human functioning. These measurements include happiness, marital success, job performance and longevity.
Explanations of human personality have a long tradition of theorising that stands outside the mainstream of trait approaches. Furthermore, modern perspectives, such as positive psychology, recent conceptual leaps in cognitive psychology and the emergence of modern psychodynamic viewpoints, are offering alternative ways of conceptualising and measuring peopleās characteristics and each has a different focus. In fact, having a variety of theoretical perspectives is valuable for understanding something as vital to humanity as personality. Not surprisingly, we still await the discovery of that single grand theory that can tell us everything we need to know about how a personās feelings, thoughts, actions, interactions, motives and preferences make up his or her complete personality. Therefore, while each approach has its merits and limitations, it is quite reasonable to āsit on the fenceā and not feel any obligation to choose one perspective as being the right one. Indeed, in this chapter, the point being made is that it is advisable to consider that there may be both conscious and unconscious routes to personality development; that examining oneās motivation for growth and development need not contradict those views that focus on peopleās conflicts within the psyche; and that measuring oneās traits as behavioural patterns does not negate the importance of exploring and understanding both the cognitive processes and neurological activities underlying those patterns. Moreover, just because many theorists and researchers of differential psychology concentrate on knowing more about those important human traits that appear to be universal, this does not undermine the significance of examining how the broader culture and experience can account for wide inter-individual differences. Major life experiences and deliberate self-development can promote intra-individual changes in peopleās personality traits at different phases across their lives. Thus, each of the different perspectives has something useful and important to offer in aspiring towards a complete picture of the multifaceted psychological constituents that make people different from each other and that define who they are as unique individuals.
The first section in this chapter compares the viewpoint that traits are an inclusive set of dispositions shared by all people against a different viewpoint that an individualās underlying traits are exclusive to only that particular person. The mainstream trait approach largely adopts the former perspective, and this is compared to the view of personality as being essentially idiosyncratic rather than comparable across every one of us. In the second section, the comparison is made between psychodynamic perspectives (that tend to focus on unresolved early life experiences and the unconscious mind) and cognitive theories (that examine the largely consciously accessible thinking habits that make people who they are). The third section addresses the issue of the role of biology versus experience on personality, examining evidence of inherited temperamental differences between individuals and discussing how experience and nature interact in the development of personality across the lifespan. The fourth section of the chapter discusses a set of theories and research about personality that can be subsumed under the umbrella of positive psychology. Historically, personality theorists have often also been clinicians with an interest in personality pathology. Positive psychology strays from this tradition by considering the overarching driving force of human nature as leaning towards healthy personality development and flourishing.
Are there universal personality traits or are people unique?
Most definitions of the term ātraitsā mention that they are consistent and stable patterns of thoughts, feelings and behaviours that differentiate people from each other. Therefore it is safe to say that we can think of the collection of individual traits that one possesses as being the linchpin of oneās personality. The major difference between different factions of personality researchers and theorists is whether to identify a set of universal traits against which people can be compared or whether to focus on a personās own underlying personality traits as particular to his or her own unique psychological make-up. Psychologists who call themselves trait theorists are usually interested in the former, identifying dispositions that apply to everyone to some extent. This is also known as the nomothetic approach to measuring personality. The idiographic approach, by contrast, emphasises the uniqueness of individual features as being most important. Those who use idiographic methods regard the underlying traits of individuals as being specific to their own set of personal experiences, values and attitudes. On the whole, it is humanistic, psychodynamic and social-cognitive researchers who choose this latter approach.
Trait theorists are concerned with ways of measuring a personās underlying dispositions or traits or are interested in assessing differences in a set of core trait dimensions in order to predict individual differences in a variety of outcomes. Research has been extensive in this regard, examining the relationship between personality traits and various measures of life choices, social roles, achievement levels and areas of satisfaction, ranging very widely from examples such as personality influences on healthy lifestyles (e.g. Hampson et al., 2006; Ozer and Benet-Martinez, 2006) and personality characteristics in the use of online social networking sites (Correa, Hinsley and De Zuniga, 2010) to examining the traits of Mount Everest climbers (Egan and Stelmack, 2003). The assumption is that we can identify a small set of universally important traits that can be measured in everyone when making predictions about outcomes. This perspective also adopts particular methods of investigation and measurement. One such method has been the lexical approach, which assumes that the trait terms appearing frequently in natural language across cultures are just those terms that are candidates for a universal taxonomy of personality traits. For example groundbreaking research in the 1930s by Allport and Odbert (1936) discovered 17,953 trait terms in the English dictionary, from which 4,500 stable traits were identified, which included adjectives such as aggressive, honest and i ntelligent. Trait theorists have proposed different organisational frameworks of traits. Allport identified three levels of traits: the cardinal trait (one that dominates), central traits (those that shape most of behaviour) and secondary traits (traits specific to particular circumstances). Interestingly while it was Allportās work that paved the way for the trait approach to identify a small set of the most significant dispositions present in all people, it was also Allport who proposed that most traits refer to relatively unique dispositions that are based on oneās own particular life experiences. Therefore, he advocated using an idiographic approach.
Trait theorists since Allport have been drawn to nomothetic methods of investigation. Using a plethora of investigative material through methods of observation, self-report and laboratory tests, the British psychologist Raymond Cattell (1943) recognised many similarities among Allport and Odbertā s trait terms and clustered these traits together into a much smaller number of trait clusters, using a statistical technique known as factor analysis. Factor analysis is an efficient way of identifying groups of trait terms that co-vary with each other (go together) and that do not co-vary with other items. Eventually, what starts as a large number of trait adjectives gets reduced right down to a much smaller set of essential core dispositions that are regarded as the main dimensions along which all people vary. Cattell refined his traits down to 16 personality factors (Cattell, Eber and Tatsuoka, 1970). Cattell also distinguished between different trait levels, including surface and source (underlying) traits, as well as further sub-categories of source traits, such as dynamic (motivational) traits and temperament traits.
Another key trait theorist is Hans Eysenck, who started off with his own theory of the biological significance of core temperaments before devising his personality inventory and using factor analytic methods of data reduction (Eysenck, 1967). Eysenck argued that extraversion/introversion (E) and emotional stability/instability (N) were the main dimensions along which all people varied. He subsequently added the trait of psychoticism (P) to his theory, although his E and N factors have gained much more supportive evidence than his P factor. By far the most popular support has been for the five-factor theory of Paul Costa and Robert McCrae (1995). An explosion of evidence has accumulated on measures of what has become known as their Big Five factors, these being openness to experience, conscientiousness, extraversion, agreeableness and neuroticism (emotional stability). Openness reflects the degree of intellectual curiosity, creativity and preference for novelty and variety a person has. Conscientiousness reflects a tendency to be organised and dependable and a preference for planned rather than spontaneous behaviour. Extraversion is characterised as showing qualities such as being energetic, assertive and sociable as opposed to choosing to keep oneās own company and a preference for quiet surroundings (introverted). Agreeableness is a tendency to be compassionate and cooperative rather than suspicious and antagonistic towards others. Finally, neuroticism is the predilection for experiencing anxiety, anger or depression. A person with low scores on this dimension is regarded as emotionally stable and not vulnerable to experiencing negative emotional reactions.
This model has been widely replicated and is shown to be remarkably robust across many large samples (Goldberg, 1990). While this chapter cannot do justice to the vast amount of research on life outcomes predicted from the Big Five, some of the key findings that have been replicated are that high conscientiousness and low neuroticism (high emotional stability) are predictive of good student grades (Chamorro-Premuzic and Furnham, 2003; Richardson, Abraham and Bond, 2012) and lower procrastination (Watson, 2001); leadership effectiveness in business is predicted by high extraversion, high openness and low neuroticism (Silverthorne, 2001); happiness is best predicted by high extraversion and low neuroticism (Cheng and Furnham, 2003); aggression towards others is predicted mostly by neuroticism (Hellmuth and McNulty, 2008), whereas neuroticism accompanied by high agreeableness reduces the frequency of angry outbursts (Barlett and Anderson, 2012). Moreover, a combination of high neuroticism, high extraversion and low conscientiousness increases the chances of risky and addictive behaviours, such as heavy alcohol consumption (Grano, Virtanen, Vahtera, Elovainio and Kivimaki, 2004); and multiple risky sexual behaviours can be predicted from low agreeableness, low openness and high extraversion (Miller et al., 2004). Finally, a recent study shows that while high extraversion predicts assertive communication, it is high levels of traits of agreeableness and openness that are linked with having high levels of active and empathic listening (Sims, 2016), a finding that suggests that while an extravert might ask questions and seek social encounters, people with āagreeableā and āopenā traits may be superior conversationalists when it comes to engaging with and considering other peopleās views and opinions.
One of the major controversies surrounding the five-factor model is whether it provides a comprehensive account of personality (Block, 1995). While there is a general consensus that the Big Five are the most relevant dimensions of personality, those who offer a cautionary position tend to consider five factors as offering too limited a scope to provide a complete account of all human characteristics. Dan McAdams (1992) has made the strong case that the five-factor model comprises a āpsychology of the strangerā āthat is the five factors describe what one might want to know if one knew nothing else about a person. These criticisms to trait approaches focus on the ārough and readyā classification of personality measured through personality inventories. Idiographic methods are recommended when one wants to gain a deeper and more thorough portrait of the desires, goals and personal identities of particular individuals.
In spite of the strong evidence of the predictive validity of the Big Five, these core traits are not perfect predictors of either current behaviour or future life outcomes. Wide variations in experience, situational complexities and developmental influences will interact with basic dispositions leading to a vast number of different possible outcomes. Therefore, while personality profiles can be useful predictors, they should not be regarded as fortune tellers.
Cross-cultural studies have also indicated that those dispositions regarded as important by researchers in American society may not be appropriate for measuring personality in other parts of the world. Sagiv and Roccas (2000) have investigated the role of cultural values in trait expression, with extraversion and openness being more readily endorsed in Western cultures, and cooperation and tradition being more valued in non-Western cultures. Some researchers have developed different factors using the natural language of their own countries. For example in China and South Africa, researchers have developed their own measures of personality as well as identifying culture-specific personality traits (Cheung, van de Vijver and Leong, 2011).
The idiographic position involves a very different approach. It assumes that people have features of personality that are personal to themselves and that each individual has his or her own life history that brings about a unique and idiosyncratic way of thinking, feeling and being. Those who adopt an idiographic approach use methods such as focus groups, interviews or in-depth case studies. These investigative approaches can yield rich and meaningful information about individuals that psychometric scales are unable to uncover. (Runyan, 1983, offers a thorough discussion of the goals and methods of the idiographic method.) One of the major criticisms of such methods is their high level of subjective interpretation and their inability to yield findings that meet the criteria of scientific validity. Humanistic, psychodynamic and social-cognitive theorists have leaned towards a focus on the unique experiences of individuals. The humanistic approach is discussed later in the section on developing a flourishing personality (positive psychology). Probably the most renowned and notorious personality psychologist, Sigmund Freud, used a clinical interview method in deve...
