Project

Activities such as smoking and exercise exert their effects over long intervals. Whiteman, Deary and Fowkes (2000) suggested that a full understanding of personality requires the integration of two models, a structural weakness model that focuses on internal vulnerabilities (e.g., genetic predispositions to illness), and a psychosocial vulnerability model that focuses on external factors such as life/work stress. Cognitive factors such as choosing health-promoting coping strategies may play a mediating role. Similarly, development of emotional competence depends on the interaction

between biologically-based elements of temperament that confer emotionality on the child, and social learning processes, such as modelling of emotional response. Individual differences in brain systems for handling reward and punishment stimuli (Philip J. Corr, Chapter 21) may govern whether children develop cheerful or distress-prone temperaments, respectively. However, the distress-prone child may still grow up to be well-adapted if he or she learns effective strategies from parents and peers for coping with vulnerability to negative emotion. Cognitions are also critical in that language capabilities influence the child’s capacity to understand and express emotion. Traits such as emotional intelligence emerge from this complex and enigmatic interactional process (Zeidner, Matthews, Roberts and McCann 2003). Finally, in this section, we note the resurgence of one of the grand theories of

personality, John Bowlby’s attachment theory, reviewed in this volume in two chapters authored by Phillip R. Shaver and Mario Mikulincer (Chapters 14, 15). Bowlby’s insight was that the child’s pattern of relationships with its primary care-giver affected adult personality; secure attachment to the care-giver promoted healthy adjustment in later life. The theory references many of the key themes of this review of personality. Attachment style may be measured by observation or questionnaire; a common distinction is between secure, anxious and avoidant styles (Ainsworth, Blehar, Waters and Wall 1978). It also corresponds to standard traits; for example, secure attachment correlates with Extraversion and Agreeableness (Carver 1997). Attachment likely possesses biological aspects (evident in etholog- ical studies of primates), social aspects (evident in data on adult relationships), and cognitive aspects (evident in studies of the mental representations supporting attachment style) (Phillip R. Shaver and Mario Mikulincer, Chapter 14). As with other personality theories, a major challenge is developing a model that integrates these different facets of the attachment construct.

Theories of personality

Allport (1937) saw personality traits as possessing causal force. Traits correspond to ‘generalized neuropsychic structures’ that modulate the individual’s understanding of stimuli and choice of adaptive behaviours. Thus, traits represent more than some running average of behaviour. For example, we could see trait anxiety as simply the integral of a plot of state anxiety over time, but this perspective tells us nothing about the underlying roots of vulnerability to anxiety.

Editors’ general introduction xxix

A theory of the trait is required to understand the causal basis for stability in individual differences, and the processes that incline the person to view stimuli as threatening, and to engage in defensive and self-protective behaviours. One of the hallmarks of personality theory is the diversity of explanatory

concepts it invokes (Susan Cloninger, Chapter 1). We could variously attribute trait anxiety to sensitivity of brain systems controlling response to threat, to cognitive processes that direct attention to environmental threat, or to culture- bound socialization to see oneself as threat-vulnerable. Three sections of this Handbook address three major perspectives that mould contrasting theories. According to biological perspectives, personality is a window on the brain. Hans Eysenck and Jeffrey Gray articulated the influential view that individual differ- ences in simple but critical brain parameters, such as arousability and sensitivity to reinforcing stimuli, can drive far-reaching personality changes, expressed in traits such as Extraversion and Neuroticism. These theories emphasized the role of individual differences in genes for brain development (polymorphisms) in gen- erating personality variation (in conjunction with environmental factors). As a broad research project, biological theory thus emphasizes studies of behaviour and molecular genetics, psychophysiology, and the linkage between neuroscience and real-world behavioural functioning, including clinical disorder. Cognitive and social-psychological theories bring different issues into the

foreground of research. The essence of cognitive theories is that personality is supported by differing representations of the world, and the person’s place within it, coupled with individual differences in information-processing. For example, Aaron Beck (Beck, Emery and Greenberg 2005) attributed depression to the negative content of self-schema, such as beliefs in personal worthlessness. Emotional pathology also relates to biases in attention, memory and strategies for coping. A major feature of cognitive approaches is the use of the experi- mental methods of cognitive psychology to link traits to specific components of information-processing. These approaches typically link cognition to real-life behaviour and adaptation through self-regulative models that seek to specify stable individual differences in the processing supporting goal attainment (Charles S. Carver and Michael F. Scheier, Chapter 24). Social psychological accounts focus on the interplay between personality and

social relationships (Lauri A. Jensen-Campbell et al., Chapter 29), and several interlocking issues. These include the extent to which personality characteristics (including traits) arise out of social interaction, the reciprocal influence of person- ality on social interaction, and the role of culture in modulating these relation- ships. Biological and cognitive theories typically conform to a natural sciences model, but at least some variants of social psychological theory owe more to the idiographic and humanistic traditions of the field discussed by Susan Cloninger (Chapter 1). Avigorous research programme that looks back to the social learning theories of Walter Mischel and Albert Bandura combines elements of both cognitive and social psychology within an idiographic framework (Caprara and Cervone 2000; Ronald E. Smith and Yuichi Shoda, Chapter 27).

xxx Editors’ general introduction

In a sense, each research tradition may stand alone. Each has its own distinct research agenda and methods supporting a self-contained domain of scientific discourse. However, each perspective on theory faces contemporary challenges that are a product of previous progress. We will review these shortly. The more general point to emphasize is that there is increasing convergence between different approaches. Cognitive and social neuroscience approaches are increasingly infusing personality research, and it is also clear that core social-psychological constructs, such as the self-concept, overlap with trait-based constructs (Matthews, Deary and Whiteman 2003). There are still unresolved issues regarding the extent to which, for example, cognitive and social accounts of personality may be reduced to neuro- science (Matthews 2008b; Corr and McNaughton 2008). It can be agreed, though, that there has never been a greater need for proponents of different research traditions to talk to one another in the service of theoretical integration. Next, we reflect briefly on some of the main challenges for each theoretical

perspective, which are taken up by contributors to this volume.

Neuroscience

The neuroscience of personality has advanced considerably from Hans Eysenck’s (1981) pioneering efforts to advance biological models as a new Kuhnian para- digm for the field. Genetic studies, psychophysiology and ‘the neuroscience of real life’ have all made major advances. The leading biological theories, such as Reinforcement Sensitivity Theory (Philip J. Corr, Chapter 21), aim to integrate various strands of evidence in delineating the neuroscience of personality. The case of heritability of personality was originally based on behaviour

genetics, and the finding that the similarity between related individuals, such as siblings, related to their degree of genetic similarity (Johnson, Vernon and Mackie 2008). The attribution of around 50 per cent of the variance in major personality traits to heritability is uncontroversial. The field has also tackled such important issues as non-additive effects of genes and gene-environment interaction. Studies of personality variation within a given population are not, however, informative about the mechanisms through which genes build the individual brains that differ in the familiar personality traits. There is currently some excitement about the prospects for molecular genetics,

i.e., identifying polymorphisms (different variants of the same gene) that may produce individual differences in neural functioning and ultimately observed per- sonality. Approaches focusing on genes for neurotransmitter function have had some success in linking personality to DNA (Marcus R. Munafò, Chapter 18). The search is on for ‘endophenotypes’ – highly specific traits that are shaped by the genes and influence broader personality traits and vulnerability to mental illness. At the same time, the likely complexity of mappings between genes, brain systems and behaviour may present a barrier to future progress (Turkheimer 2000). There is also growing interest in the evolutionary basis for human neural functio-

ning. Initially, evolutionary psychology was more concerned with personality in the sense of ‘how all people are the same’, rather than with individual differences.

Editors’ general introduction xxxi

Recently, however, researchers (e.g., Penke, Dennisen and Miller 2007) have begun to explore how evolutionary genetic mechanisms may produce variation in traits across individuals. Aurelio José Figueredo et al. (Chapter 16) point out that varia- bility in strategies for managing social relationships, including sexual relationships, may be critical for human personality. Furthermore, the evolutionary perspective aligns with growing evidence for continuity between animal and human personality (or temperament), as Samuel D. Gosling and B. Austin Harley (Chapter 17) discuss. Research methodology has also advanced since the heydays of Hans Eysenck

and Jeffrey Gray. The traditional indices of central and autonomic arousal remain important, but contemporary brain-imaging methods offer the prospect of trans- forming personality neuroscience. Two chapters in this volume (Turhan Canli, Chapter 19; Colin G. DeYoung and Jeremy R. Gray, Chapter 20) review how methods such as functional magnetic resonance imaging (fMRI) establish associa- tions between personality traits and specific brain areas. Excitement about such research has justification. At the same time, much remains to be done to go beyond establishing correlations between traits and neurology, to develop causal models that explain the correlations. It also remains to be seen whether the psychometric models based on questionnaire data will prove adequate to capture personality variation seen at the neural level (Ian J. Deary, Chapter 6).

Cognitive science of personality

For forty years or so, cognitive-psychological research on personality has traded quite successfully on the insights and methods of the ‘cognitive revolution’ of the 1960s. As previously indicated, major themes include the importance of stable self-knowledge, studies of information-processing using objective performance indices, and the concept of self-regulation as an approach to handling dynamic interaction between the person and the outside world. The use of language in the assessment of personality also raises important issues regarding the role of cognitive representations and semantics (Gerard Saucier, Chapter 22). Theoretical landmarks include schema theories of emotional pathology (Beck, Emery and Greenberg 2005), information-processing accounts of anxiety and impulsivity (Eysenck, Derakshan, Santos and Calvo 2007; Revelle 1993) and the cybernetics of self-regulation (Carver and Scheier 1998). As in other realms of personality, these well-established theories face new

challenges. We will briefly highlight three of these here: the scope of cognitive models, the relevance of social psychology, and the development of causal models of person-situation interaction. The first issue is whether cognitive personality theories can really explain the full range of personality phenomena. It is something of a cliché to say that cognitive models suggest a dehumanized, robot-like perspective on human functioning (although, arguably, one based on a misunder- standing of cognitive science: Matthews, Zeidner and Roberts 2002). By contrast, investigations of the emotional basis of personality have been a staple of the field, addressed from multiple perspectives (Rainer Reisenzein and Hannelore Weber, Chapter 4). Recent work on emotional intelligence (Mayer, Salovey and Caruso

xxxii Editors’ general introduction

2000) suggests that there may be affective elements of personality that are not easily reduced to cognitive processes. Positive psychology emphasizes the gen- erative role of emotions in signalling peak experiences and personal fulfilment (cf., Edward L. Deci and Richard M. Ryan, Chapter 25). It is also unclear whether cognitive theories can accommodate renewed interest

in unconscious processes. Although the classical psychodynamic theories have their defenders, most cognitive psychologists see only weak parallels, at most, between the Freudian unconscious and the unconscious information-processing revealed by experiments on information-processing (Kihlstrom 1999). Of more interest is that stable traits can be revealed through implicit behavioural measures, whose place in some over-arching dimensional model of personality remains to be explored (Schnabel, Banse and Asendorpf 2006). A second challenge comes from social psychological approaches that situate

both cognition and personality within social interaction. The self-schema may be attributed to generalized self-knowledge relevant to all individuals (Michael D. Robinson and Constantine Sedikides, Chapter 26; Wells and Matthews 1994). We can assess self-esteem, for example, using standard instruments – and relate the measurements to traits such as neuroticism. The contrasting social-psychological perspective is that self-related constructs can only be understood in the context of social relationships and the cultural milieu (Caprara and Cervone 2000). Not only is the self shaped through social interaction, but it is negotiated via discourse with others; so that it resides ‘between’ rather than ‘within’ people (Hampson 1988). A potentially important compromise between social constructivism of this kind and conventional cognitive theory was advanced by Mischel and Shoda (1995). Social learning may lead to the development of organized networks of cognitive- affective processing units that support the individual’s unique patterns of inter- action with the social world (Ronald E. Smith and Yuichi Shoda, Chapter 27). The third issue here is the causal role of individual differences in cognition in

generating personality differences. Information-processing models typically establish correlations between traits and multifarious processing components (Gerald Matthews, Chapter 23), but it remains unclear whether processing causes personality or vice versa. Recent work on anxiety (Wilson, MacLeod, Mathews and Rutherford 2006) establishes a causal role for processing: training participants to respond to threat stimuli appears to increase anxiety (stress vulnerability). At the same time, trait anxiety relates to processing biases and strategic preferences that influence cognitions of threat. Self-regulative theories may be usefully extended by specifying reciprocal relationships between personality traits and specific processing functions that support adaptation to external social environ- ments (Matthews 2008a).

Social psychology and personality

Traditional social psychological approaches to personality face the converse issue to cognitive theories; that is, much of what has been seen as uniquely social about personality may, in fact, be understood in terms of trait constructs and the

Editors’ general introduction xxxiii

individual’s mental representations. As previously discussed, many of the core attributes of the self such as self-esteem and self-efficacy may be represented as generalized self-knowledge (Matthews, Schwean, Campbell et al. 2000; Michael D. Robinson and Constantine Sedikides, Chapter 26). This perspective supports empirical work on the interplay between personality and social relationships (Lauri A. Jensen-Campbell et al., Chapter 29) that shows how various social processes are biased by traits. For example, highly agreeable individuals broadly view others more positively, express higher empathy, and adopt more helpful and constructive interaction strategies. An understanding of traits may similarly inform research on social support (Rhonda Swickert, Chapter 30) and social emotions such as the hurt of rejection (Geoff MacDonald, Chapter 31). As Lauri A. Jensen-Campbell et al. (Chapter 29) also discuss, effects of personality on social functioning must be understood in the broader context of reciprocal interaction between personality and social relations across the lifespan. Social-psychological research is also increasingly exploring the wider cultural

context of personality. The traditional argument is that culture shapes the social interactions which, in turn, shape the self and personality. This view continues to inform cross-cultural studies (see Juris G. Draguns, Chapter 32; Matsumoto 2007) that explore how contrasting social values such as individualism and collectivism are expressed in personality in cultures such as the United States and East Asia. At the same time, the cultural relativism traditionally promoted by anthropology has been challenged by the new awareness of universal human nature supported by evolutionary psychology and empirical evidence for the generality of personality structure. Research is needed on the extent to which ‘universal personality’ constrains cultural variability in personality (Robert Hogan and Michael Harris Bond, Chapter 33). At the time of writing, the United States is in the midst of a presidential primary

season that appears highly driven by (perceptions of) the personalities of the candidates. The obsession of contemporary Western culture with celebrities is also widely acknowledged. Another frontier for social personality research is to investigate the role of such personality perceptions in the public arena. This new focus on personality builds on earlier research on the influence of personality on political attitudes, such as Adorno’s classic work on authoritarian personality. As Gianvittorio Caprara and Michele Vecchione (Chapter 34) discuss, effects of personality transcend simple right-left divisions, and must be understood within a cultural context.

Psychopathology and abnormality

Abnormal personality and its role in mental illness has been a major focus of inquiry since Freud’s initial studies of ‘hysteria’ (Eysenck and Eysenck 1985). As with other areas of personality research, research centres on issues of conceptualization, measurement and theoretical understanding. In addition, the

xxxiv Editors’ general introduction