The Wiley-Blackwell Handbook of Individual Differences E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Geisteswissenschaft
• Serie: HPIZ - Wiley-Blackwell Handbooks in Personality and Individual Differences
• Sprache: Englisch

Seitenzahl: 1869

Veröffentlichungsjahr: 2011

Beschreibung

The Wiley-Blackwell Handbook of Individual Differences provides a comprehensive, up-to-date overview of recent research, current perspectives, practical applications, and likely future developments in individual differences. 

• Brings together the work of the top global researchers within the area of individual differences, including Philip L. Ackerman, Ian J. Deary, Ed Diener, Robert Hogan, Deniz S. Ones and Dean Keith Simonton
• Covers methodological, theoretical and paradigm changes in the area of individual differences
• Individual chapters cover core areas of individual differences including personality and intelligence, biological causes of individual differences, and creativity and emotional intelligence 

Leseprobe

Table of Contents

Cover

Table of Contents

Praise for The Wiley-Blackwell Handbook of Individual Differences

Wiley-Blackwell Handbooks in Personality and Individual Differences

Title page

Copyright page

List of Plates

List of Figures

List of Tables

List of Contributors

Preface

List of Abbreviations

Part I: Individual Differences: An Up-to-Date Historical and Methodological Overview

1 Individual Differences and Differential Psychology: A Brief History and Prospect

Early Differential Psychology and Its Application

Differential Psychology in the Late Nineteenth and Early Twentieth Centuries

Mid-Twentieth Century: The High Point of Differential Psychology?

The Late Twentieth Century

2000–2010

Current Status and Future Directions

Conclusion

2 Methodological Advances in Differential Psychology

Coomb’s Theory of Data and Cattell’s Data Box

Methods of Data Collection

Types of Design

Experimental Approaches

Observational Approaches

Methods of Analysis

Conclusion

Part II: Intelligence and Personality: Structure and Development

Section 1 Personality

3 Personality Development across the Life Span

Mean-Level Change

Rank-Order Consistency and Change

Patterns and Explanations of Rank-Order Consistency

Sources of Rank-Order Change

Future Research

Conclusion

4 Reinforcement Sensitivity Theory, Research, Applications, and Future

1 Foundations of RST

2 RST and Personality

3 RST and Psychopathology

4 RST and Achievement Motivation

5 A Long Way to the Top: A Challenge for Future RST Research

Acknowledgments

5 The General Factor of Personality: Normal and Abnormal

1 Introduction

2 Historical Background, Including Charles Darwin and Francis Galton

3 Life History Theory

4 The GFP in the EAS Temperament Survey

5 The GFP in the Guilford–Zimmerman Temperament Survey

6 The GFP in the California Psychological Inventory

7 The GFP in the Temperament and Character Inventory

8 The GFP in the Comrey Personality Scales

9 The GFP in the Multidimensional Personality Questionnaire

10 The GFP in the Minnesota Multiphasic Personality Inventory–2

11 The GFP in the Millon Clinical Multiaxial Inventory

12 The GFP in the Personality Assessment Inventory

13 The GFP in the Dimensional Assessment of Personality Pathology

14 The GFP in Emotional Intelligence (and HEXACO)

15 The GFP and Subjective Well-Being

16 Evolutionary Genetics

17 Neurobiology

18 Construct Validity

19 Discussion

6 Five into One Doesn’t Go: A Critique of the General Factor of Personality

The Theory of the General Factor of Personality

Evidence for the GFP

Evaluating the Psychometric Evidence

Artifact or Substance?

Good Guys and Bad Guys

Evolutionary Perspectives on the GFP

Additional Challenges

Conclusions

Future Research Directions

Section 2 Intelligence

7 The Nature and Structure of “Intelligence”

1 Introduction

2 “Intelligence” as Cognitive Abilities: Psychometric Models

3 Intelligence as Developed Intellect and Other Models

4 Concluding Comments

Acknowledgments

8 Re-Visiting Intelligence–Personality Associations: Vindicating Intellectual Investment

1 Theoretical Perspectives

2 (Overcoming) Current Research Obstacles

9 Individual Differences in Cognitive Aging

When Does Cognitive Aging Begin and for What Cognitive Abilities?

To What Extent Do Individual Differences Exist in Aging-Related Cognitive Changes?

How Many Explanations Are Needed for Cognitive Aging?

What Are the Moderators of Cognitive Aging?

What Can Improve Cognitive Performance in Adulthood?

How Does Cognitive Aging Relate to Real-World Functioning?

What Are the Neurobiological Substrates of Individual Differences in Cognitive Aging?

What Are the Genetic Risk Factors for Cognitive Aging?

Conclusions, Outlook, and Future Directions

Part III: Biological Causes of Individual Differences

10 Behavior Genetics

Introduction

The Twin Method, Its Underlying Assumptions, and a Cautionary Note

Individual Psychological Differences and Behavior Are Heritable

New Developments

Molecular Genetics

Conclusions and Future Directions

11 Molecular Genetic Aspects of Personality

1 Introduction

2 Foundations and Methods

3 Candidate Gene Approaches: Theories Informing about Gene–Trait Associations

4 Molecular Genetic Main Effects

5 Gene–Gene and Gene–Environment Interactions, and Pleiotropic Gene Effects

6 Future Directions

12 Understanding Human Intelligence by Imaging the Brain

The Brain Connection

What Is Intelligence?

The Measurement of Intelligence: Implications for Neuroimaging Studies

Imaging Intelligence: Methods

Findings

Final Remarks

13 Evolutionary Psychology and Individual Differences

Individual Differences in Evolved Adaptations

Typology of Individual Differences

Evolutionary Explanations of Individual Differences

How to Synthesize Evolutionary Psychology and Individual Differences: An Illustration

Conclusion

Part IV: Individual Differences and Real-World Outcomes

Section 1 Work

14 Individual Differences at Work

Usefulness in Prediction and Explanation

Current and Future Directions for Individual Differences Workplace Applications

15 Leadership

1 Introduction

2 Defining Leadership

3 Leadership and Organizational Effectiveness

4 Personality and Leadership

5 Leadership and Business Unit Performance

6 What Do Followers Want?

7 Bad and Unethical Leadership

8 Shared Team Leadership

9 Leadership Training

10 Conclusion

Section 2 Health, Longevity, and Death

16 Cognitive Epidemiology: Concepts, Evidence, and Future Directions

Introduction

A Brief History

Finding Roots in Epidemiology

Pre-Morbid Intelligence and Risk of Total Mortality

Specific Causes of Morbidity and Mortality

Intelligence–Disease Mechanisms, and the Future for Cognitive Epidemiology

Conclusion

Acknowledgments

17 Personality and Differences in Health and Longevity

Personality and Differences in Health and Longevity

History and Background

Disease-Prone Personalities and Self-Healing Personalities

Measuring Personality

Measuring Health Outcomes

The Importance of Multiple Causal Linkages

The Five-Factor Model and Health Outcomes

Conclusion

Section 3 Society

18 Personality and the Laws of History

Introduction

Some Simple Rules for Human Nature

Some Collective Dynamics

Collective Histories

Personality and Culture

How Individual Personality Shapes Collective History

The Origins of the Capacity for Evil

Concluding Remarks

Acknowledgments

19 Individual Differences and Antisocial Behavior

1 Introduction

2 Genetics, Crime, and Antisocial Behavior

3 Why Is Antisocial Behavior Heritable?

4 Possible Mechanisms for Antisocial Behavior

5 Biopsychosocial Processes

6 Personality and Antisocial Behavior

7 Intelligence, IQ, and Antisocial Behavior

8 Conclusions

Acknowledgments

20 Intelligence and Social Inequality: Why the Biological Link?

1 Introduction

2 Meaning and Measurement of Social Inequality

3 Meaning and Measurement of Intelligence

4 Individual-Level Status Attainment Processes

5 The Democratic Dilemma

Part V: Motivation and Vocational Interests

21 Goal-Setting: A State Theory, but Related to Traits

Individual Differences

Summary and Conclusions

Acknowledgments

22 Personality and Approaches to Learning

1 Introduction

2 Taxonomic and Measurement Consensus

3 Approaches to Learning (ATL)

4 Measures of Approaches to Learning

5 Personality and Approaches to Learning and Learning Style

6 Educational Preferences

7 Teaching Methods

8 Assessment Method

9 Conclusion

23 Vocational Interests: The Road Less Traveled

Holland’s Structural Formulations

Gender Differences in Interests

Continuity and Change of Interests

Integrated Models

Conclusion

Part VI: Competence beyond IQ

Section 1 Special Abilities

24 Exceptional Talent and Genius

Introduction

Genius versus Talent

Psychometric versus Historiometric Methods

Generic versus Domain-Specific Profiles

Nature versus Nurture

Individual versus Situation

25 Ability and Trait Emotional Intelligence

History and Background

Problems with Ability EI: Why Emotional Intelligence Is Not a Real Intelligence

Trait Emotional Intelligence

Applications of Trait Emotional Intelligence

Experimental Studies in Trait EI

26 Individual Differences in Creativity

Personality

Intelligence

Gender, Ethnicity, and Creativity

Creativity across Culture: East versus West

Gender Differences in Creativity

Conclusion

Acknowledgments

Section 2 Relationships and Subjective Well-Being

27 Personality and Happiness: Predicting the Experience of Subjective Well-Being

The Construct of SWB

Theoretical Perspectives on SWB

Research Methods in the Study of SWB

SWB and Temperament-Level Personality Traits

Heredity, Temperament, and SWB

SWB and Other Personality Traits

Ongoing Issues for Future Research

Summary

28 Self-Esteem: Enduring Issues and Controversies

What Is Self-Esteem?

How Is Self-Esteem Measured?

What Are the Basic Demographic Correlates of Self-Esteem?

How Is Self-Esteem Related to Other Individual Differences Constructs?

Is Self-Esteem Associated with Life Outcomes?

Further Reflections on the Debate over the Benefits of Self-Esteem

Is Self-Esteem a State or a Trait?

What Are the Age-Related Differences in Self-Esteem across the Life Span?

Is Self-Esteem a Universal Construct or a By-Product of Individualistic Cultures?

Conclusions

29 Love at First Sight? Individual Differences and the Psychology of Initial Romantic Attraction

Attraction as a Dynamic Process

The Case of Florentino Ariza, or the Observer

The Case of Fermina Daza, I: Perceived Traits

The Case of Fermina Daza, II: Real Traits

Conclusion

30 Manifestations of Individual Differences in Physical and Virtual Environments

How Do Individual Differences Impact Everyday Contexts?

Scope and Methodology of Review

The Expression of Individual Differences in Everyday Environments

Index

Plates

Praise for The Wiley-Blackwell Handbook of Individual Differences

Fresh and comprehensive, this meaty volume provides an unusually deep discussion of individual differences. With the recent explosion of research, the time is right for this wonderful update. Don’t look for this handbook on my bookshelves—it will be on my desk and in use.

Robert B. Kaiser, Partner, Kaplan DeVries Inc., USA

Some of the world’s top researchers give us authoritative and engaging overviews of the central topics in individual differences, such as personality, creativity, intelligence, genetics and evolution, work, motivation, special abilities and happiness, making this a comprehensive guide for understanding how and why people differ.

Robert Plomin, Research Professor, Institute of Psychiatry, King’s College London, UK

This handbook provides a diverse multidisciplinary collection of chapters by leading researchers. Domains covered range from intelligence to personality, interests, and motivation—and from basic research on brain functions to real-world implications in the workplace and beyond.

Phillip L. Ackerman, Professor of Psychology, Georgia Institute of Technology, Atlanta, USA

There is much in this handbook that does not simply summarize present knowledge but foreshadows the future state of differential psychology. Of use to the beginning student as well as the seasoned psychologist, any serious psychology library should possess this handbook.

Philip J. Corr, Professor of Psychology, University of East Anglia, UK

This impressive collection of antecedents, contemporary theory, and the latest empirical research does not shy away from controversial stances or highlighting consensual elements of the field, making this a must-read for students, practitioners, and researchers alike.

Richard D. Roberts, Principal Research Scientist, Research and Development, Educational Testing Service, USA

With contributions from many leading researchers in differential psychology, The Wiley-Blackwell Handbook of Individual Differences provides an up-to-date and comprehensive overview of individual differences research. This book will be a valuable resource for anyone interested in the field.

Tony Vernon, Professor of Psychology, University of Western Ontario, USA

With thoughtful and well-written chapters—ranging from the genetics of individual differences, to the relation between intelligence and personality, to the traces that different individuals leave behind in their physical environments—this handbook manages to be both highly readable and thoroughly informative.

Colin G. DeYoung, Assistant Professor of Psychology, University of Minnesota, USA

Wiley-Blackwell Handbooks in Personality and Individual Differences

This important series of handbooks provides a cutting-edge overview of classic, contemporary and future trends in research across Personality and Individual Differences. Each handbook draws together a collection of newly commissioned chapters to provide a comprehensive examination of a sub-discipline in the area.

The international teams of editors and contributors to the handbooks have been specifically chosen for their expertise and knowledge of each particular subject.

The Wiley-Blackwell Handbooks in Personality and Individual Differences will provide an invaluable resource for advanced students and researchers as an authoritative definition of their chosen field.

This edition first published 2011

© 2011 Blackwell Publishing Ltd

Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing program has been merged with Wiley’s global Scientific, Technical, and Medical business to form Wiley-Blackwell.

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Library of Congress Cataloging-in-Publication Data

The Wiley-Blackwell handbook of individual differences / [edited by] Dr Tomas Chamorro-Premuzic, Sophie von Stumm, Adrian Furnham.

p. cm. -- (Wiley-Blackwell handbooks in personality and individual differences; 1)

Includes bibliographical references and index.

ISBN 978-1-4443-3438-8 (hardback); ISBN 978-1-4443-4311-3 (ebk)

 1. Individual differences--Handbooks, manuals, etc. 2. Personality--Handbooks, manuals, etc. 3. Intelligence--Handbooks, manuals, etc. I. Chamorro-Premuzic, Tomas. II. Von Stumm, Sophie. III. Furnham, Adrian.

BF697.W4933 2011

155.2'2--dc22

2010047214

A catalogue record for this book is available from the British Library.

List of Contributors

Phillip L. Ackerman, School of Psychology, Georgia Institute of Technology

Ghufran Ahmad, IAE-Aix (Graduate School of Management)/INSEAD (The Business School of the World)

Marcel A. G. van Aken, Utrecht University

Patrick Ian Armstrong, Iowa State University

Rachel E. Avery, Goldsmiths, University of London

G. David Batty, University of Edinburgh

Silvia Bonaccio, University of Ottawa

Burkhard Brocke, Department of Psychology, Dresden

Catherine M. Calvin, University of Edinburgh

Tomas Chamorro-Premuzic, Goldsmiths, University of London

Roberto Colom, Universidad Autónoma de Madrid

David M. Condon, Northwestern University

Ian J. Deary, University of Edinburgh

Jaap J. A. Denissen, Humboldt-University Berlin

Ed Diener, University of Illinois at Urbana-Champain

M. Brent Donnellan, Michigan State University

Vincent Egan, University of Leicester

Eamonn Ferguson, University of Nottingham

Howard S. Friedman, University of California

Adrian Furnham, University College London

Deshani B. Ganegoda, University of Central Florida

Samuel D. Gosling, University of Texas at Austin

Linda S. Gottfredson, University of Delaware

Lindsay T. Graham, University of Texas at Austin

Robert Hogan, Hogan Assessment Systems

Paul Irwing, University of Manchester

Wendy Johnson, University of Edinburgh

Satoshi Kanazawa, London School of Economics and Political Science

James C. Kaufman, California State University at San Bernardino

Margaret L. Kern, University of California

Gary P. Latham, University of Toronto

Edwin A. Locke, University of Maryland

Natalie J. Loxton, University of Queensland

Deniz S. Ones, University of Minnesota-Twin Cities

William Pavot, Southwest Minnesota State University

K. V. Petrides, University College London

Alan Pickering, Goldsmiths, University of London

Charlie L. Reeve, University of North Carolina

William Revelle, Northwestern University

Brent W. Roberts, University of Illinois at Urbana-Champaign

Richard W. Robins, University of California

James Rounds, University of Illinois at Urbana-Champaign

J. Philippe Rushton, University of Western Ontario

Timothy A. Salthouse, University of Virginia

Carson J. Sandy, University of Texas at Austin

Dean Keith Simonton, University of California

Luke D. Smillie, Goldsmiths, University of London

Frank M. Spinath, Saarland University

Alexander Strobel, Department of Psychology, Dresden

Sophie von Stumm, University of Chichester

Rong Su, University of Illinois at Urbana-Champaign

Viren Swami, University of Westminster

Paul M. Thompson, Laboratory of Neuroimaging, Los Angeles

Kali H. Trzesniewski, University of Western Ontario

Elliot M. Tucker-Drob, University of Texas at Austin

Chockalingam Viswesvaran, Florida International University

Alexander Weiss, University of Edinburgh

Joshua Wilt, Northwestern University

Preface

In essence, individual differences research aims to understand how and why individuals vary in their affect, behavior, cognition, and motivation. To this end, researchers in this field seek to accurately describe, explain, and measure dimensions of individual differences, to evaluate the long-term consequences of such differences, and to discover their etiologies, including their biological, environmental, and genetic bases. They employ a wide range of research tools and theoretical approaches, spanning psychometrics, brain imaging, and behavior and molecular genetics amongst many others. As a result, an overwhelming body of multifaceted evidence demonstrates that individuals differ along continua of affect, behavior, cognition, and motivation, most of which can be understood and operationalized in terms of quantifiable trait dimensions, such as intelligence and personality.

Even though individual differences are evident beyond psychological research papers, to anyone who has ever interacted with another human being, questions concerning their assessment, consequences, and etiologies remain sensitive and controversial. The idea that individuals may differ naturally and meaningfully—particularly in abilities—challenges eighteenth-century American and European ideologies of equal creation, which continue to shape Western societies, their governments, and policies (not to mention the tragic case of communist regimes). Indeed, individual differences research proclaims that there are robust, inevitable, and salient differences between and within people that are partly heritable and have long-term consequences. Admittedly, this knowledge was and is easily (ab)used to justify selection and discrimination, thereby confirming the status quo as irremediable and legitimate.1 However, the possibility of malpractice and a clash with prevailing ideals do not suffice to discard a scientific discipline as thriving, exciting, and fruitful as individual differences, even if it has not, to date, gained comparable recognition inside or outside academic circles.

Therefore this handbook was developed with two closely related goals in mind. For one, we sought to compile an up-to-date volume that comprehensively spanned the diversity of individual differences research, its methods, and most recent findings as a strong, global foundation for understanding and studying individual differences. Secondly, we also hoped to demonstrate the potential and importance of individual differences as a research discipline, highlighting the knowns as much (or more) as the unknowns, so as to encourage future analyses of how and why individuals differ.

The book comprises six main sections. In the first section, William Revelle and colleagues review the historical development of individual differences and introduce the fundamental methodological tools and advances of the research discipline. The second section is dedicated to the structure and development of personality and intelligence, focusing particularly on the diverse theoretical and psychometric conceptualizations of personality, as well as on the interplay of ability and non-ability factors. In the third section, biological causes of individual differences are investigated from four specific but related perspectives: behavior genetics, molecular genetics, brain imaging, and evolutionary approaches. The fourth section puts individual differences in the context of the “real world,” evaluating their role and function for work and leadership; for health, longevity, and death; as well as for society, considered from historical and present-day perspectives. The fifth section addresses the often overlooked theme of the importance of individual differences in motivation and vocational interests for academic, occupational, and personal goal achievement. The final section involves competencies beyond intelligence, such as exceptional talent, emotional intelligence, and creativity (an area of research that was almost imposed on academics by the “real-world” audience, including practitioners and decision-makers in the fields of education and human resources). This section also evaluates the importance of individual differences in love, happiness, confidence, and environmental manifestations.

With contributions from almost 60 seminal individual differences experts, this book was written for scholars and students with an interest of any kind in the psychology of individual differences. This volume may also be of interest to audiences in education and business. The chapters are written at a level comprehensible for advanced undergraduate students and the “intelligent layman” (this phrase does not intend to imply that most laymen are unintelligent).

We are grateful to Wiley-Blackwell for encouraging us to work on this project (and for always taking us out to nice restaurants—may this tradition continue for many years, regardless of the success of our Handbook and of any other projects we work on); in particular, we would like to thank “the two As” (Andy McAleer and Andy Peart, at Wiley-Blackwell). We also thank our contributors for their speedy delivery of chapters and their friendly cooperation even when they had to respond to our rather bullish and repetitive requests—editing a book is not easy, and we have learned a lot from this project (so much that we will probably edit more books in the future).

Finally, we would like to thank and dedicate this book to the following people (and here is where the editors split, for one time only):

Tomas Chamorro-Premuzic dedicates this book to Don Roberto de Baja Georgia, for his continued support, guidance, and friendship throughout this entire project—and hopefully beyond.

Sophie von Stumm dedicates this book to her grandparents, for what they were, are, and always will be to her.

Adrian Furnham dedicates this book to Benedict, his beloved son.

The editors, London, August 1, 2010

Note

1 Such reasoning also constitutes a logical short-circuit: heritability does neither imply specific genetic effects, nor does it undercut the importance of environmental factors or the malleability of traits throughout development.

List of Abbreviations

ACE

additive genetic influences model, common shared environment model, and unique individual environment model

ACE

Angiotensin I Converting Enzyme

ACTIVE

Advanced Cognitive Training for Independent and Vital Elderly Study Group

AD

Alzheimer disease

Add Health

Adolescent Health

ADHD

attention deficit hyperactivity disorder

ANPS

Affective Neuroscience Personality Scales

AP

Advanced Placement

APOE

Apolipoprotein E

ARP

Annual Review of Psychology

ASI

Approaches to Studying Inventory

ASRM

affective startle reflex modulation

ASVAB

Armed Services Vocational Aptitude Battery

ATL

approaches to learning

BA

Brodmann area

BAS

behavioral activation system

BFI

Big-Five Inventory

BFQ–C

Big Five Questionnaire—Children

BiLSAT

Bielefeld Longitudinal Study of Adult Twins

BIS

behavioral inhibition system

BMI

body mass index

BNST

bed nucleus of the stria terminalis

BOLD

blood–oxygen-level dependent

bp

base pair

BPAQ

Buss–Perry Aggression Questionnaire

CEO

chief executive officer

CFA

confirmatory factor analysis

CHC

Carroll–Horn–Cattell

CHD

coronary heart disease

CI

confidence interval

CMC

computer-mediated communication

COMT

Catechol-O-Methyltransferase

COPS

criterion-focused occupational personality scales

CPI

California Psychological Inventory

CPS

Comrey Personality Scales

CSF

cerebrospinal fluid

CTA

cues–tendency–action

CV

confounding variable

CVD

cardiovascular disease

CWB

counterproductive work behavior

DAPP–BQ

Dimensional Assessment of Personality Pathology–Basic Questionnaire

DC

dichorionic

DIF

differential item functioning

DNA

deoxyribonucleic acid

DRD4

dopamine D4 receptor

DRM

Day Reconstruction Method

DSM

Diagnostic and statistical manual of psychiatric disorders

DTI

diffusion tensor imaging

DZ

dizygotic

EAR

electronically activated recorder

EAS

EAS Temperament Scales

EDS

Environment Description Scale

EEA

equal environments assumption

EEG

electroencephalography

EFA

exploratory factor analysis

EI

emotional intelligence

EPI

Eysenck Personality Inventory

EQi

Emotional Quotient Inventory

ERP

event-related potential

ESM

experience-sampling method

ESS

evolutionary stable strategy

F1, F2, F3, F4

each of the four first-order factors

FA

factor analysis

FA

fractional anisotropy

FACS

facial action coding system

FFFS

fight–flight–freeze system

FFM

five-factor model

FFS

fight–flight system

fMRI

functional magnetic resonance imaging

g–e

gene–environment

G × E

genome–environment

Gc

crystallized intelligence

Gf

fluid intelligence

GFP

general factor of personality

Glr

long-term storage and retrieval intelligence

GM

gray matter

GMA

general mental ability

GOSAT

the German Observational Study of Adult Twins

Gq

quantitative intelligence

GR

glucocorticoid receptor

GRE

Graduate Record Examinations

Grw

reading and writing intelligence

Gs

processing speed intelligence

Gsm

short-term memory intelligence

GSOEP

the German Socio-Economic Panel

GSS

general social survey

Gt

decision speed/reaction time intelligence

Gv

visual processing intelligence

GWAS

genome-wide association studies

GZTS

Guilford–Zimmerman Temperament Survey

HA

harm avoidance

HDL

high-density lipoprotein

HEXACO

HEXACO Personality Inventory

HOME

Home Observation for Measurement of the Environment

HPI

Hogan Personality Inventory

HR

hazard ratio

IAT

implicit association test

ICBM

International Consortium for Brain Mapping

ICC1.1

intra-class correlation

ICD

International Classification of Diseases

Ins/Del

insertion/deletion

IPA

intelligence–personality association

IPAR

Institute for Personality Assessment and Research

IPDE

international personality disorder examination

IPIP

International Personality Item Pool

IRT

item response theory

IV

independent variable

JPI

Jackson Personality Inventory

KMO

Kaiser–Meyer–Olkin

L

long

LOD

logarithm [base 10] of odds

LONI, UCLA

Laboratory of Neuroimaging

MAO–A

monoamine oxidase A

MBTI

Myers–Briggs Type Indicator

MC

monochorionic

MCMI–III

Millon Clinical Multiaxial Inventory

MCQ

multiple-choice question

MD

mean diffusivity

MDS

multidimensional scaling

MIDUS

midlife development in the US

MMPI

Minnesota Multiphasic Personality Inventory

MPQ

Multidimensional Personality Questionnaire

MRI

magnetic resonance imaging

mRNA

messenger RNA

MSCEIT

Mayer–Salovey–Caruso Emotional Intelligence Test

MTMM

multi-trait–multi-method

MTR

Methionine Synthase

MZ

monozygotic

NA

negative affect

NEAD

Nonshared Environment Adolescent Development Project

NFC

need for cognition

NLSY

National Longitudinal Survey of Youth

NPI

Narcissistic Personality Inventory

NS

novelty-seeking

NSHD

National Survey of Health and Development

OCB

organizational citizenship behavior

OECD

Organization for Economic Cooperation and Development

OR

odds ratio

OSN

on-line social networking site

OSS

Office of Strategic Services

P–FIT

parieto-frontal integration theory of intelligence

PA

positive affect

PAI

Personality Assessment Inventory

PANAS

Positive and Negative Affect Schedule

PCA

principal components analysis

PCL–R

revised Psychopathy Checklist

PCR

polymerase chain reaction

PD

personality disorder

PDE4D

phosphodiesterase-4D

PEN

psychoticism—extraversion—neuroticism model

PET

positron emission tomography

PIQ

non-verbal IQ score

PISA

Programme for International Student Assessment

PLS

personal living space

PLSCI

Personal Living Space Cue Inventory

PMA

primary mental abilities

PPIK

(intelligence as) process, personality, interests, and (intelligence as) knowledge

PRF

Personality Research Form

PV

person variable

PWB

psychological well-being

RAPM

Raven Advanced Progressive Matrices Test

RASI

Revised Approaches to Studying Inventory

RD

reward dependence

rGE

gene–environment correlation

RFT

regulatory focus theory

RIASEC

realistic, investigative, artistic, social, enterprising, and conventional type

RNA

ribonucleic acid

ROI

return on investment

RSE

Rosenberg Self-Esteem Scale

RST

reinforcement sensitivity theory

S

short

SAPA

synthetic aperture personality assessment

SAT

Scholastic Assessment/Ability Test

SB5

Stanford–Binet 5 Test

SCN

the suprachiasmatic nuclei

SD

standard deviation

SDS

Self-Directed Search

SEM

structural equation modeling

SES

socioeconomic status

SISE

single-item self-esteem measure

SLODR

Spearman’s law of diminishing returns

SLS

Seattle Longitudinal Study

SMPY

Study of Mathematically Precocious Youth

SMS

Scottish Mental Survey

SNAP25

synaptosomal-associated protein 25

SNP

single-nucleotide polymorphism

SOI

Sociosexual Orientation Inventory

SOI

structure of intellect

SPANE

Scale of Positive and Negative Experience

SPQ

Study Process Questionnaire

SPT

set-point theory

SSREI

the schutte self-report emotional intelligence scale

SSRI

selective serotonin reuptake inhibitor

STARTS

Stable Trait–Autoregressive Trait State

STAT

Sternberg Triarchic Abilities Test

STEM

science, technology, engineering, and mathematics

SWB

subjective well-being

TAI

temperament, ability, and interests

TCI

Temperament and Character Inventory

TEDS

Twins’ Early Development Study

TEIQue

Trait Emotional Intelligence Questionnaire

TIE

typical intellectual engagement

TMS

transcranial magnetic stimulation

TPH2

tryptophan hydroxylase 2

TPQ

Tridimensional Personality Questionnaire

TTCT

Torrance Tests of Creative Thinking

TWH

Trivers–Willard hypothesis

UCB

University of California, Berkeley

VBM

voxel-based morphometry

VES

Vietnam Experience Study

VIQ

verbal IQ score

VNTR

variable number of tandem repeats

VPR

visual–perceptual–rotational

WAIS

Wechsler Adult Intelligence Scale

WJ–III

Woodcock–Johnson Revised Test

WM

white matter

WMC

working-memory capacity

5–HT

serotonin

5–HTT

serotonin transporter

5–HTTLPR

serotonin transporter-linked promotor regions

16PF

the Sixteen Personality Factors Inventory

Part I: Individual Differences An Up-to-Date Historical and Methodological Overview

1

Individual Differences and Differential PsychologyA Brief History and Prospect

William Revelle, Joshua Wilt, and David M. Condon

This handbook is devoted to the study of individual differences and differential psychology. To write a chapter giving an overview of the field is challenging, for the study of individual differences includes the study of affect, behavior, cognition, and motivation as they are affected by biological causes and environmental events. That is, it includes all of psychology. But it is also the study of individual differences that are not normally taught in psychology departments. Human factors, differences in physical abilities as diverse as taste, smell, or strength are also part of the study of differential psychology. Differential psychology requires a general knowledge of all of psychology; for people (as well as chimpanzees, dogs, rats, and fishes) differ in many ways. Thus differential psychologists do not say that they are cognitive psychologists, social psychologists, neuro-psychologists, behavior geneticists, psycho­metricians, or methodologists; for, although we do those various hyphenated parts of psychology, by saying that we study differential psychology we have said we do all of those things. And that is true for everyone reading this handbook. We study differential psychology: individual differences in how we think, individual differences in how we feel, individual differences in what we want and what we need, individual differences in what we do. We study how people differ, and we also study why people differ. We study individual differences.

There has been a long recognized division in psychology between differential psychologists and experimental psychologists (Cronbach, 1957; H. J. Eysenck, 1966), however, the past 30 years have seen progress in the integration of these two approaches (Cronbach, 1975; Eysenck, 1997; Revelle & Oehlberg, 2008). Indeed, one of the best known experimental psychologists of the 1960s and 1970s argued that “individual differences ought to be considered central in theory construction, not peripheral” (Underwood, 1975, p. 129). However, Underwood went on to argue (p. 134) that these individual differences are not the normal variables of age, sex, IQ, or social status, but rather the process variables that are essential to our theories. Including these process variables remains a challenge to differential psychology.

The principles of differential psychology are seen outside psychology in computer science simulations and games, in medical assessments of disease symptomatology, in college and university admissions, in high school and career counseling centers, as well as in applied decision-making.

Early Differential Psychology and Its Application

Differential psychology is not new; for an understanding of research methodology and individual differences in ability and affect was described as early as the Hebrew Bible, in the story of Gideon (Judges 6: 37–40, 7: 2–6). Gideon was something of a skeptic, who had impressive methodological sophistication. In perhaps the first published example of a repeated-measures crossover design, he applied several behavioral tests to God before agreeing to go off to fight the Midians, as he was instructed. Gideon put out a wool fleece on his threshing floor and first asked that by the next morning just the fleece should be wet with dew, but the floor should be left dry. Then, the next morning, after this happened, as a crossover control, he asked for the fleece to be dry and the floor wet. Observing this double dissociation, Gideon decided to follow God’s commands. We believe that this is the first published example of the convincing power of a crossover interaction. (See Figure 1.1, which has been reconstructed from the published data.)

Figure 1.1 Gideon’s double dissociation test. Gideon’s testing of God is an early example of a double dissociation test, and probably the first published example of a crossover interaction. On the first night, the wool was wet with dew but the floor was dry. On the second night, the floor was wet but the wool was dry (Judges 6: 36–40)

In addition to being an early methodologist, Gideon also pioneered the use of a sequential assessment battery. Leading a troop of 32,000 men to attack the Midians, Gideon was instructed to reduce the set to a more manageable number (for greater effect upon achieving victory). To select 300 men from 32,000, Gideon (again under instructions from God) used a two-part test. One part measured motivation and affect by selecting those 10,000 who were not afraid. The other measured crystallized intelligence, or at least battlefield experience, by selecting those 300 who did not lie down to drink water but rather lapped it with their hands (McPherson, 1901).

Gideon thus combined many of the skills of a differential psychologist. He was a methodologist versed in within-subject designs, a student of affect and behavior, and someone familiar with basic principles of assessment. Other early applications of psychological principles to warfare did not emphasize individual differences as much as the benefits of training troops in a phalanx (Thucydides, as cited by Driskell & Olmstead, 1989).

Personality Taxonomies

That people differ is obvious. How and why they differ is the subject of taxonomies of personality and other individual differences. An early and continuing application of these taxonomies is most clearly seen in the study of leadership effectiveness. Plato’s (429–347 BC) discussion of the personality and ability characteristics required of the hypothetical figure of the philosopher–king emphasized the multivariate problem of the rare co-occurrence of appropriate traits:

… quick intelligence, memory, sagacity, cleverness, and similar qualities, do not often grow together, and that persons who possess them and are at the same time high-spirited and magnanimous are not so constituted by nature as to live orderly and in a peaceful and settled manner; they are driven any way by their impulses, and all solid principle goes out of them. […] On the other hand, those steadfast natures which can better be depended upon, which in a battle are impregnable to fear and immovable, are equally immovable when there is anything to be learned; they are always in a torpid state, and are apt to yawn and go to sleep over any intellectual toil. […] And yet we were saying that both qualities were necessary in those to whom the higher education is to be imparted, and who are to share in any office or command.

(Plato, 1892: The republic, VI, 503c–e)

Similar work is now done by Robert Hogan and his colleagues as they study the determinants of leadership effectiveness in management settings (Hogan, 1994, 2007; R. Hogan, Raskin, & Fazzini, 1990; Padilla, Hogan, & Kaiser, 2007) as well as by one of the editors of this volume, Adrian Furnham (Furnham, 2005). The dark-side qualities discussed by Hogan could have been taken directly from The Republic.

A typological rather than dimensional model of individual differences was developed by Theophrastus—or rather Tyrtamus of Eresos, in Lesbos (372–287 BC), a student of Aristotle who, according to his teacher, acquired the nickname “Theophrastus” (“the one who speaks like a god”) for his oratorical skills. Theophrastus is famous today as a botanical taxonomist. But he is also known to differential psychologists as a personality taxonomist, who organized the individual differences he observed into a descriptive taxonomy of “characters.” The Characters of Theophrastus is a work often used to illustrate and epitomize the lack of coherence of early personality trait description; however, it is possible to organize his “characters” into a table that looks remarkably similar to equivalent tables of the late twentieth century (John, 1990; John & Srivastava, 1999; see Table 1.1).

Table 1.1 Theophrastus’s character types and the traits of the “Big Five” show remarkable similarity. “Big Five” adjectives taken from John, 1990; Theophrastus’s Characters presented in Jebb’s translation of 1870

One thousand and six hundred years after Theophrastus, Chaucer added to the use of character description in his Canterbury Tales, which are certainly the first and probably the “best sequence of ‘Characters’ in English Literature” (Morley, 1891, p. 2). This tradition continued into the seventeenth century: the character writings of that period are a fascinating demonstration of the broad appeal of personality description and categorization (Morley, 1891).

Causal Theories

Theophrastus asked a fundamental question of personality theory, which is still of central concern to us in personality theory today:

Often before now have I applied my thoughts to the puzzling question—one, probably, which will puzzle me for ever—why it is that, while all Greece lies under the same sky and all the Greeks are educated alike, it has befallen us to have characters so variously constituted.

(Theophrastus, 1870: Characters, p. 77)

Table 1.2 Greek and Roman causal theory of personality

Physiological basisTemperamentYellow bileCholericPhlegmPhlegmaticBloodSanguineBlack bileMelancholic

This is, of course, the fundamental question asked today by differential psychologists who study behavior genetics (e.g. Bouchard, 1994, 2004) when they address the relative contribution of genes and of shared family environment as causes of behavior.

Biological personality models have also been with us for more than two millennia, through the work of Plato, Hippocrates, and, later on, Galen, all of which had a strong influence. Plato’s placement of the tripartite soul into the head, the heart, and the liver and his organization of it into reason, emotion, and desire remain a classic organization of the study of individual differences (Hilgard, 1980; Mayer, 2001; Revelle, 2007). Indeed, with the addition of behavior, the study of psychology may be said to be the study of affect (emotion), behavior, cognition (reason), and motivation (desire), as organized by Plato (but without the physical localization).

About 500 years later, the great doctor, pharmacologist, and physiologist Galen (AD 129–ca216) unified and systematized the earlier literature of the classical period, particularly the work of Plato and of the medical authors of the Hippocratic Corpus, when he described the causal basis of the four temperaments. His empirical work, based upon comparative neuroanatomy, aimed to provide support for Plato’s tripartite organization of soul into affect, cognition, and desire. Although current work does not use the same biological concepts, the search for a biological basis of individual differences continues to this day.

Eighteen centuries later, Wilhelm Wundt (1874, 1904) reorganized the Hippocratic–Galenic four temperaments into the two dimensional model later discussed by Hans Eysenck (1965, 1967) and Jan Strelau (1998).

Early Methodology

In addition to Gideon’s introduction of the crossover experiment, Plato introduced two important concepts, which would later find an important role in psychometrics and in the measurement of individual differences. Something similar to the modern concept of true score and to that of a distinction between observed and latent variables may be found in the celebrated “allegory of the cave” at the opening of Book VII of Plato’s Republic (VII, 514a ff.). For, just as the poor prisoners chained to the cave wall must interpret the world through the shadows cast on the wall, so must psychometricians interpret individual differences in observed score as reflecting latent differences in true score. Although shadow length can reflect differences in height, it can also reflect differences in distance from the light. For the individual differences specialist, making inferences about true score changes on the basis of observed score differences can be problematic. Consider the increases in observed IQ scores over time, reported by Flynn (1984, 1987, 2000), which are known as the “Flynn effect.” It may be asked, is the Flynn effect a real effect, and are people getting smarter, or are the IQ scores going up in a process equivalent to the change in shadow length in the cave, say, because of a change in position, but not one of height in the real world? This inferential problem is also seen in interpretations of fan-fold interactions as reflecting interactions at the latent level rather than merely at the observed level (Revelle, 2007).

Table 1.3 Wundt’s two-dimensional organization of the four temperaments

 ChangeabilityExcitabilityMelancholicCholericPhlegmaticSanguine

Differential Psychology in the Late Nineteenth and Early Twentieth Centuries

Any discussion of differential psychology must include the amazing contributions of Sir Francis Galton. Apart from considering the hereditary basis of ability (Galton, 1865, 1892), describing the results of an introspective analysis of the complexity of his own thoughts (Galton, 1879), or introducing the lexical hypothesis, later made popular by Goldberg (1990), by searching the thesaurus for multiple examples of character (Galton, 1884), Galton also developed an index of correlation in terms of the product of deviations from the median and of the probable error of the estimate (Galton, 1888; see Stigler, 1989). His measure of “reversion to the mean” was later modified to the form we now know as “the Pearson product moment correlation coefficient” (Pearson, 1896).

Galton believed in the power of data analysis, whether it was developing meteorological maps of Europe, the use of fingerprints for identification, or the dimensions of character:

… character ought to be measured by carefully recorded acts, representative of the usual conduct. An ordinary generalization is nothing more than a muddle of vague memories of inexact observations. It is an easy vice to generalize. We want lists of facts, every one of which may be separably verified, valued and revalued, and the whole accurately summed. It is the statistics of each man’s conduct in small every-day affairs that will probably be found to give the simplest and most precise measure of his character. […] [A] practice of deliberately and methodically testing the character of others and of ourselves is not wholly fanciful, but deserves consideration and experiment.

(Galton, 1884, p. 185)

Expanding upon the work of Galton, Charles Spearman, in a remarkable pair of papers in 1904, introduced to psychologists the correlation coefficient as well as the concept of reliability and corrections for attenuation:

Psychologists, with scarcely an exception, never seem to have become acquainted with the brilliant work being carried on since 1886 by the Galton–Pearson school. The consequence has been that they do not even attain to the first fundamental requisite of correlation, namely a precise quantitative expression.

(Spearman, 1904a, p. 96)

In the next issue of the same journal, Spearman then introduced factor analysis and suggested a general factor of ability (1904b). More than a century after these papers, much of differential psychology may be seen as a footnote to the work of Galton and Spearman.

The research of Gerard Heymans (1908) in the Netherlands unfortunately has not received the attention it deserves among American psychologists; for it is a classic set of studies on the structure of individual differences, one based on observer ratings. Eysenck has presented a very thorough review of Heymans’s work (Eysenck, 1992), as has Strelau (1998). Van der Werff and Verster (1987) reanalyzed the data using principal components analysis. In the original studies, over 3,000 physicians were asked to rate the members of one family on six types of items. About 400 physicians responded. Strelau summarizes the results, classifying them according to temperamental dimensions of activity, emotionality, and “primary vs. secondary functioning.” This latter dimension may be taken as related to Introversion–Extraversion or to the temporal aspects of behavior and to the speed of switching between activities (see Atkinson & Birch, 1970 and Fua, Revelle, & Ortony, 2010 for a consideration of the temporal component). The original data reanalyzed in this way included 90 questions referring to 2,309 members of 437 families. A five-component and a three-component solution were obtained. The components represented: (1) impulsivity versus thoughtfulness; (2) activity (with two sub-components, one of continuous activity and one of “not easily daunted” activity); and (3) “bad temper” versus “good temper,” which encompassed items like trusting and unselfish versus imperious and irritable. Strelau (1998) pays these important studies the respect they deserve.

The early twentieth century also saw the introduction of the IQ test (Binet & Simon, 1905; Goddard, 1908; Terman, 1916); the introduction of the hypothesis of a general factor of ability (Spearman, 1904b); and the introduction of ability (the Army Alpha test) and emotional testing for military selection (Driskell & Olmstead, 1989; Jones & Thissen, 2007; Yerkes, 1918). Differential psychologists involved in the Army Alpha/Beta project included Terman, Otis, Thorndike, Thurstone, and Whipple (Jones & Thissen, 2007). Otis went on to develop a group intelligence scale, as did Terman. The subsequent years were active times for differential psychology, seeing as they did the beginnings of the landmark longitudinal study of high-ability children (Terman, 1925; Terman & Oden, 1947). It was also a time in which IQ tests were used to screen (non-English-speaking) immigrants at Ellis Island in the United States and to argue for forced sterilization (Zenderland, 2001) for those with low scores.

Another researcher whose work has not been as appreciated by Americans as much as it should is William Stern (1910, 1914). Not only laying out a theory of differences between individuals, Stern also emphasized the study of individuality, which he wanted to reclaim from historical biographers (Stern, 1910). It is interesting to note that he was well aware of the problem of errors of memory that bias self-reports of any kind. His lectures should be of interest to all those interested in narrative approaches to the study of individuals. Stern is best known for his work on intelligence (Stern, 1914), where he developed the measure of intelligence as the ratio of mental age to chronological age. This ratio, when multiplied by 100, of course became the IQ score used in differential psychology before the change to the use of standard scores. To Stern,

Intelligence is a general capacity of an individual consciously to adjust his thinking to new requirements: it is a general mental adaptability to new problems and conditions of life.

Finally, the fact that the capacity is a general capacity distinguishes intelligence from talent the characteristic of which is precisely the limitation of efficiency to one kind of content. He is intelligent, on the contrary, who is able easily to effect mental adaptation to new requirements under the most varied conditions and in the most varied fields. If talent is material efficiency, intelligence is a formal efficiency.

(Stern, 1914, pp. 3–4)

Subsequent work on the structure of ability followed the introduction of matrix algebra to Thurstone (Thurstone, 1935, 1947), and thus into psychology (Bock, 2007). With the ability to work with matrices, the process of applying the factor analysis of correlational “tables” became much simpler and the subsequent extraction of multiple factors of intellect more reasonable. Debates between theories of general intelligence (“g” theories) (Spearman, 1946), multi-factor models (Thurstone, 1933, 1935, 1947), and sampling theories of intelligence (Bartholomew, Deary, & Lawn, 2009; G. H. Thomson, 1935; S. Thomson, 1951) filled the pages of journals and the shelves of libraries.

Outside of the ability domain, empirically driven test construction in the personality and interests domains proceeded with little regard for theories of underlying individual differences. This work led to the development and validation of items that could discriminate known occupational groups from people in general. The basic principle was—and is—that, if one shares interests with people of a particular occupation, one is more likely to do well in that occupation (Strong, 1927). Interests show strong consistencies over the lifetime (Kelly, 1955) and have moderate predictive validities. More recently, two- and three-dimensional structural models have been applied to interest, as the latter were measured by the Strong Interest Inventory (Armstrong, Smith, Donnay, & Rounds, 2004; Donnay, 1997). Interests shared with those in an occupation do not imply that one has an ability for that occupation (one may share interests with opera singers, but, if one is a second monotone—that is, unable to carry a note—one is unlikely to succeed in what opera singers do).

Mid-Twentieth Century: The High Point of Differential Psychology?

The 1930s saw the creation of the journal Psychometrika, the pages of which were soon filled with detailed discussions on reliability theory, factor analysis, and scale construction. Most of the work was on measuring ability, and the primary debates were between methods of factor extraction, validity estimation, and a general theory of tests.

With the publication of Gordon Allport’s text on personality (Allport, 1937), Henry Murray’s integration of multiple approaches to the study of personality (Murray, 1938), and Clyde Kluckhohn and Murray’s integration of personality with society and culture (Kluckhohn & Murray, 1948), empirical personality research had finally reached the United States.

Following the onset of the Second World War, differential psychologists were soon involved in problems of selection and training. About 1,500 psychologists were associated with the Army Air Force selection and training program. The list of differential psychologists involved includes many future presidents of the Psychometric Society (Jones & Thissen, 2007) and leaders in differential psychology. The detailed final report of the project (Dubois, 1947) is a primer on how to do validity studies. The point biserial validities for cognitive and psychomotor tests for predicting training success, for example for pilots, navigators, and bombardiers, were roughly .45 across various samples and could be presented graphically in a manner that showed the powers of selection (Figure 1.2).

Figure 1.2 Success rate in Army Air Force elementary pilot classes as a function of the ability scored in stanines. Cohorts 43 H–K. Figure adapted from tables in Dubuis, 1947, p. 119. While only about 20% of candidates with the lowest stanine succeeded, almost 95% of the top stanines did. Sample sizes in each cohort range from 9, 617 to 11,010

Differential psychologists primarily associated with personality and social psychology were also involved in selection, but in selection for more difficult criteria. Differential psychologists assisted with the selection of agents for the Office of Strategic Services (OSS), which later became the Central Intelligence Agency. Whereas the criteria for air force pilots were clear, the criteria for success as a spy proved to be more difficult to ascertain. The predictive validities actually diminished the longer the assessment procedure lasted (OSS Assessment Staff, 1948; Wiggins, 1973).

Three more “milestones” in assessment and prediction involving differential psychology (Wiggins, 1973) were the American Veterans Administration selection of clinical psychology graduate students in the late 1940s (Kelly & Fiske, 1951), the selection of the first American astronauts, and the selection of Peace Corps Volunteers (Wiggins, 1973).

The conclusions from the VA selection study (Kelly & Fiske, 1950) are remarkably consistent with findings reported 50 years later about predicting graduate student success (Kuncel, Hezlett, & Ones, 2001): a mixture of ability and objectively assessed interests and personality variables predicts graduate student success with roughly equal (≈ .25–.30) validities, which, when combined, form a multiple correlation, R, of about .4. More importantly, and in tune with the OSS findings, complex assessments based upon the interactions of assessors with applicants have no incremental validity. That is, people who are more able, interested in psychology, and lack nervous tension and irritability are more likely to succeed in clinical training than the less able, less interested, and more nervous. Having long interactions with an assessment board does not add information to this combination of temperament, ability, and interests (TAI).

Theories of Individual Differences

The late 1940s through to the mid-1960s were a major time for theorizing about individual differences. In terms of theories of intellect, Joy P. Guilford’s attempt to cross three modes of thinking—operations, products, and content—led to an ambitious attempt to measure 120 narrow factors of mental ability (Guilford, 1956, 1959). Each mode of thought had sub-components, such that operations could be divided into five: cognition, memory, divergent thinking, convergent thinking, and evaluation (Guilford, 1956); products could be divided into six: units, classes, relations, systems, transformations, and implications; and contents could be split into four: figural, symbolic, semantic, and behavioral.

An alternative model, suggesting a hierarchy of abilities, was the fluid, crystallized, g model of ability (the Gf–Gc model: Horn & Cattell, 1966), which made a distinction between processing factors (fluid) and knowledge factors (crystallized).

Raymond Cattell integrated cognitive and non-cognitive personality variables when he laid out an ambitious plan to apply factor analytic methods from ability to the personality domain and commenced a long series of studies on the structure of personality (Cattell, 1943, 1946a, 1946c, 1946b, 1957, 1966b, 1978). To Cattell (1946c), surface traits were clusters of observations such as self-reports of anxiety, crying, or depression; they needed to be explained by source traits, which could be derived from factor analysis. He elaborated the source/trait distinction in terms of those that reflect ability, those that are dynamic, and those that are stable temperaments (Cattell, 1946b). Cattell (1946c) introduced the data box, which emphasized that correlations can be taken over people, tests, or occasions. Although most research at the time emphasized the correlations of tests across people (R analysis), Cattell proposed to consider how people varied across tests (Q analysis), how tests varied across time (P analysis), and so on. Subsequently, Cattell (1966a) elaborated the data box into a five-dimensional analysis by adding observers and background conditions. In a series of studies using peer ratings of personality as well as self-reports, Cattell (1957) emphasized many correlated factors of personality, in what would eventually become his Sixteen Personality Factors Inventory (16PF). As a reflection of his belief in the power of differential psychology and in the need to integrate it with experimental psychology, Cattell was a founding member and first president of the Society for Multivariate Experimental Psychology in 1960.