Overview
Differential Psychology
Trait & Dispositional
Perspectives on Personality
• Introduction to Trait & Dispositional
perspectives on Personality
• Personality Types
• Personality Traits
• The Big Five
• A critical view on Big Five
Dr Andreas Fichtinger
Major Themes & underlying Assumptions
An Introduction to Trait & Dispositional
Perspectives on Personality
• Dispositional approach is traditional, classic approach
to psychological study of personality
• Since early Greek civilisation (probably longer) it has
been recognised that people are profoundly different in
– physical ways
– but also in psychological ways
• Dispositional approach creates systems for classification
& describing psychological characteristics for which…
– people differ consistently between situations & over time
Major Themes & underlying Assumptions
Types, Traits & Factors in Studying
Personality
• Dispositional approach to personality emphasises…
– “qualities that are somewhat part of people”
– “a person’s inherent qualities & character” (Carver & Scheier, 2000)
• Type approach
– Types vary in strength from person to person (i.e. needs & motives)
– categorical descriptions of characteristic patterns of thinking,
behaviour & feeling
Concept
Brief Description
Personality
Type
Each person has one predominant personality
type (e.g. Psychopathic or Type B personality)
NB: concept of type has fallen out of favour.
Personality
Trait
Traits are characteristics that influence type.
For instance, what are the traits/characteristics of
a psychopath? Thus traits describe a narrower
scope of behaviour than type.
Personality
Factor
A factor is a statistical measure of traits that
belong together. E.g. Catell’s 16 PF is an
attempt to make sense of some 18,000
personality traits originally identified.
• Trait approach - clearly emphasises dispositional approach
– Traits consistently found dimensions of thinking, behaviour & feeling
– allow people to be placed on continuum of different traits
1
Dispositional approaches to
Personality: Traits & Types
Underlying Assumptions
There are 2 major assumptions underlying a
dispositional approach:
Traits
1.
Types
• continuous
• degree (how?)
• quantitative
• ordinal
• score on x-y factor
• discontinuous
• discrete (what?)
• qualitative
• categorical
• x or y
x--------------------------y
x
Stability of personality
•
People display consistency in actions, thoughts &
feelings between situations & over time
•
•
2.
Differences between people
•
y
Major issues & related topics
Hence, predictability is rule!
Idea behind this assumption: “You are the same
person you used to be and will be in the future”
•
Composition of dispositions varies from person to
person
Each person’s personality consists of a unique
pattern of dispositional qualities
Major issues & related topics cntd.
Major issues & topics related to dispositional
perspective include:
• To what extent do personality dispositions
change over time?
• How many personality types are there & what are they?
• Are there personality differences between…
• How many personality traits are there & what are they?
• To what extent are the various personality types & traits
heritable?
• What is the relative influence of situational influences vs.
personality dispositions in determining thinking,
behaviour & feeling in specific real situations?
–
–
–
–
…people of different ages?
…men and women?
…people who work in different types of jobs?
…across cultures, ethnic groups, nations?
NB: to answer all these questions is beyond scope of
this session, but some of the answers will be
provided.
Personality Types
• Personality Type theory aims to classify people into
distinct categories (i.e. type)
Personality Types
– Personality type = Personality style
• Types refer to categories that are (i) distinct and (ii)
discontinuous
– e.g. you are the one or the other
– “You are either introvert or extrovert”
– (NB Trait theorists would say you can be anywhere on a
continuum ranging from introversion to extraversion)
• Hence, important to understand the difference between
Personality Types and Personality Traits
2
The Four Humors – Ancient Greeks
• Hippocrates & Galen classified four types of “humors”
(i.e. personalities) in people
• Each type believed to be due to an excess of four bodily
fluids, corresponding to their character.
Somatotypes – William Sheldon
• Sheldon (in 1940’s) classified personality
according to body type.
• He called this a person’s somatotype
Somatotype
Character
Humor
Fluid
Corresponding
Trait in Big 5
Irritable
Choleric
Yellow bile
Agreeableness
Depressed
Melancholic
Black bile
Neuroticism
Optimistic
Sanguine
Blood
Openness
Calm
Phlegmatic
Phlegm
Neuroticism
Myers-Briggs Type Indicator (MBTI)
Character
Shape
Endomorph
[viscerotonic]
Relaxed, sociable,
tolerant, peaceful,
comfort loving
plump, buxom, developed,
visceral structure
Mesomorph
[somatotonic]
Active, assertive,
vigorous, combative
muscular
Ectomorph
[cerebrotonic]
Quiet, fragile,
restrained, sensitive
lean, delicate, poor
muscles
Picture
Myers-Briggs Type Indicator
• Myers-Briggs Indicator, a commercially available
questionnaire is widely used in business & training
– Based on C.G. Jung’s theory & typology
• Provides information and exercises for better
understanding of
– one’s own personality &
– others with who the individual interacts & works
• Underlying all these typologies are four personality traits
(functions)
–
–
–
–
Extroversion – Introversion
Intuition (N) – Sensing (S)
Thinking (T) – Feeling (F)
Judgement (J) – Perception (P)
Type of Social
Interaction
Extrovert (E)
Preference for
Gathering Data
Sensing (S)
Introvert (I)
Intuitive (N)
Feeling (F)
Preference for
Decision Making
Thinking (T)
Style of
Decision Making
Judgmental (J)
Perceptive (P)
• Have a look at: http://www.myersbriggs.org
Type A vs. Type B Personality
• Friedman (1940), an American Cardiologist
noticed that chairs in his waiting room got worn
out from the edges
• Hypothesised that his patients were driven,
impatient people who sit on edge of chair.
→ Friedman developed new personality approach:
– Type A: a person who has an intense desire to achieve, is
extremely competitive, and has a strong sense of urgency (and
more likely to suffer heart problems!)
– Type B: A person who tends to be easygoing and relaxed.
Strengths & Weaknesses of
Personality Type Approaches
Strengths:
• Simple applicability & person-centred relevance
• Useful to complete personality type profiles for
helping people improve getting along in
relationships & at work
Weaknesses
• Over simplistic because overlook multidimensional & continuous nature of personality
traits
• Individual differences may be qualitative, not
quantitative
3
Definition
Personality Traits
Traits
• Hypothetic constructs
• Consistent patterns in
way individuals
behave, feel, & think
– measurable
– objevtive?
• Three major functions:
1. summarise/ describe
2. predict
• Focus on the structural
organisation of
personality
– NOT on development
or origin of behaviours
or characteristics
• “Personality traits are differences among
individuals in a typical tendency to behave,
think, or feel in some conceptually related
ways, across a variety of relevant
situations and across some fairly long
period of time”. (Ashton, 2005)
Personality traits as psychological
determinants of consistent behaviour
WHAT ARE PERSONALITY TRAITS?
•
•
•
•
General descriptions of individuals
Internal characteristics of the individual
Causal determinants of repetitive behaviours
Explain and predict systematic differences as well as
similarities between individuals.
3 EXAMPLES
– NOT on specific
behaviours/ behaviour
modification
a) Pete is a selfish guy
b) Lea is a happy girl
c) Sven is incredibly obsessive
3. explain
Goals of Trait Theorists
• Identify the traits necessary to explain
important human behaviours
– assume that behaviour can be explained by
operation of traits
• Measure traits accurately
– NEO-PI/ NEO-PI R; MMPI; etc.
• Eventually look for causes of trait
development
– e.g. biological/ evolutionary perspective
Theoretical assumptions
1. Dispositions/ traits are relatively stable &
enduring
•
Focus on identifying the most “important” traits
•
e.g. the “Big Five”
2. Dispositions influence behaviours in most
situations
–
“Person/ situation debate”
3. Differences among individuals arise because
of differences in strengths of traits
•
Traits are dimensional, and are present in the
population in a normal distribution
4
Measuring Traits: Structured
Personality Inventories
Strategies of
Personality Inventory Construction
• Self- or Observer Reports: are methods most
frequently used to assess personality
• Most personality inventories:
– Assess different traits
– Each trait by it’s own scale
– Scale contains several items, to allow good
reliability and validity
– Contain reverse coded or negatively keyed
items.
Factor Analysis
• A statistical tool for
summarising how a large
number of variables is
related
• Advantage:
– Reduction of number of
variables
– Identification of groups of
inter-related variables
• Correlations might reflect
underlying factors/
constructs
Item Content
1. I like to meet
people
→
• Empirical Strategy: large item pool
empirically obtained reports
correlation to
outside variable
→
• Rational Strategy: create items specifically for
reports
each trait that is to be measured
relation between items
→
→
→
• Factor Analytic Strategy: item pool
factor
correlated items are put together in
analysis
the same category
→
The Birth of Trait Theory
Factor
Number
I
II
.90
.06
2. I like parties
.80
.02
3. I like figuring
out answers to
difficult problems
.05
.75
4. I try my hardest
to do well in
school
.01
.80
• Gordon Allport (1897-1967) – father of Trait theory
• A visit with Freud early in his career solidified his view
that psychoanalysis “may plunge too deep, and that
psychologists would do well to give full recognition to
manifest motives before probing the unconscious” (Allport)
• Usefulness & intuitiveness of traits
– Traits described in literature & philosophy throughout time
Allport cntd.
• “Personality is the dynamic organisation within
the individual of those psychophysical systems
that determine his unique adjustments to his
environment”
– Dynamic: personality is constantly developing
and changing
– “Almost all the literature of character… proceeds on the
psychological assumption that each character has certain
traits peculiar to himself which can be defined though the
narrating of typical episodes from life”. (Allport, 1960)
– Traits are basic units of personality grounded in nervous
system.
Types of Traits
• Cardinal traits: dominate and pervade most aspects of
a person’s life; not all people show cardinal traits
– e.g. Marquise de Sade (sadism), Joan of Arc (heroic self-sacrifice)
• Central traits: have a major influence on a person’s
life
– These are the traits that are most characteristic of a person
– Psychophysical: neither purely mental nor purely
neutral
• Secondary traits: operate in limited settings
– Determine: traits cause behaviour, desire,
motivation
NB Allport does not propose which traits are cardinal,
central, etc., but instead suggests that this differs
across individuals
– Situation based?
5
Raymond Cattell (1905-1998)
Cattell’s Structure
• Personality “permits prediction of what a
person will do in a given situation”.
• Surface traits: response tendencies that
can be observed in various situations
• True units of personality should show up
across different types of data
• Source traits: Core internal psychological
structures that are the underlying cause of
the observed inter-correlations among
surface traits
• Factor analysis the key to developing an
objective, empirically-derived taxonomy of
personality.
• Cattell identified 16 Source traits (16 PF)
Factors in Cattell’s 16 PF
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Factor A:
Factor B:
Factor C:
Factor E:
Factor F:
Factor G:
Factor H:
Factor I:
Factor L:
Factor M:
11.
12.
13.
14.
15.
16.
Factor N:
Factor O:
Factor Q1:
Factor Q2:
Factor Q3:
Factor Q4:
Warmth (reserved vs. warm)
Reasoning (concrete vs. abstract)
Emotional stability (reactive vs. emotionally stable)
Dominance (deferrential vs. dominant)
Liveliness (serious vs. lively)
Rule-Consciousness (expedient vs. rule conscious)
Social Boldness (shy vs. socially bold)
Sensitivity (utilitarian vs. sensitive)
Vigilance (trusting vs. vigilant)
Abstractedness (grounded/practical vs.
abstracted/imaginative)
Privateness (forthright vs. private)
Apprehension (self-assured vs. apprehensive)
Openness to change (traditional vs. open to change)
Self-reliance (group oriented vs. self-reliant)
Perfectionism (tolerates disorder vs. perfectionistic)
Tension (relaxed vs. tense)
Hans J. Eysenck (1916-1997)
• Eysenck’s three-factor theory was influenced by
– Factor analysis
– Psychologists who studied personality types (e.g. Jung)
– Experimental work on classical conditioning by Pavlov
• Eysenck believed that psychoanalysis failed to provide
reliable & valid measures of personality constructs
• He believed that sound measures of individual
differences were necessary to identify the biological
foundations of traits
• Eysenck recognised that without understanding the
biology of traits, trait explanations could be circular
Eysenck’s
Three-Factor (PEN) Theory (1965)
•
Originally a two-factor theory
–
•
Psychoticism added later
Finally, he defined through factor analysis
Three Superfactors
1. Introversion-Extraversion
2. Neuroticism (stable-unstable)
3. Psychoticism (vs. Socialisation)
– Psychoticism a lot like Agreeableness plus
Conscientiousness (see Big Five below)
•
Biological underpinnings of all 3 traits!
Hierarchical Structure of
Extraversion-Introversion (E)
• E is the Super Trait
• Narrower traits include:
–
–
–
–
–
–
–
–
–
Sociable
Lively
Active
Assertive
Sensation seeking
Carefree
Dominant
Surgent
venturesome
6
Hierarchical Structure of
Neuroticism (N)
Extraversion traits
(Eysenck & Eysenck, 1985)
• N is the Super Trait
• Narrower traits include:
Traits that make up extraversion
Source: Maltby, Day, Macaskill (2010). Personality, Individual Differences and Intelligence. Prentice Hall.
–
–
–
–
–
–
–
–
–
Anxious
Depressed
Guilt feelings
Low self esteem
Tense
Irrational
Shy
Moody
Emotional
Hierarchical Structure of
Psychoticism (P)
Neuroticism traits
• P is the Super Trait
• Narrower traits include:
–
–
–
–
–
–
–
–
–
Aggressive
Cold
Egocentric
Impersonal
Impulsive
Antisocial
Unempathic
Creative
Tough-minded
Traits that make up Neuroticism
Source: Maltby, Day, Macaskill (2010). Personality, Individual Differences and Intelligence. Prentice Hall.
Psychoticism traits
Arrival of the Big Five
Traits that make up Psychoticism
Source: Maltby, Day, Macaskill (2010). Personality, Individual Differences and Intelligence. Prentice Hall.
7
The Five-Factor Model
Evidence for the lexical hypothesis
• Basic idea: finding a set of personality trait
categories that account for all the important
personality traits
• Lexical approach: using an already existing list
of traits
• Those individual differences that are most
salient & socially relevant in people’s lives
become encoded into their language
– the more likely it is to become expressed as a single
word.
Source: Oxford Concise Thesaurus, Oxford, UK: Oxford University Press, 1999
The Five-Factor Model: History
• Allport & Odbert (1936)
– 17,953 trait terms
– 4,500 are “stable traits”
• Cattell (1943)
– Factor analysis of 171 of
these “stable traits”
• 35 clusters
• Fiske (1949)
– Reduced this to 22
– Factor analysis results in
5 factors
• Tupes & Christal (1961)
– replicate Fiske
• Norman (1963) replicates
Tupes & Christal, and
writes a review about
these “Big Five” traits
– Surgency (extraversion)
– Agreeableness
What’s the Fifth Factor?
• Agreement on:
– Emotional stability (vs.
Neuroticism)
– Extraversion
– Agreeableness
– Conscientiousness
• Controversy over the
fifth factor:
– culture
– Intellect
– Intellectance
– Imagination
– Openness
– Emotional stability
– Openness to
experience
– culture
– Etc.
– Conscientiousness
Why the Big Five?
• Two independent teams (Costa & McCrae) &
(Goldberg & Norman) used factor analysis
and obtained the big five factors
• Further research has confirmed the big 5
exist regardless of culture & language
• Widely accepted & used in the personality
theory & testing world
• 80 % trait descriptors fit into the Big 5
What are the Big Five?
(McRae & Costa, 1997 version)
* Neuroticism
* Extraversion
* Openness to Experience
* Agreeableness
* Conscientiousness
NEO Personality Inventory (NEP-PI)
developed to measure these factors
8
NEO-PI-R Five Factor Inventory
• Questionnaire associated with Big Five Model
(developed by Costa & McCrae)
The Big Five Model of Personality
Neuroticism
The tendency to experience negative
emotional states and view oneself and the
world around negatively.
Extroversion
The tendency to experience positive emotional
states and feel good about oneself and the
world around.
Openness to
Experience
The extent to which a person is original, has
broad interests, and is willing to take risks.
Agreeableness
The tendency to get along well with others.
• Designed to provide a description of normal personality
• Authors argue strongly for use of questionnaires to
assess personality
– Costa & McCrae are critical of projective tests
• Current version has 243 items
– takes app. 45 minutes to complete
• Five point scale is used & person self-assesses how
certain statement is characteristic/ uncharacteristic to
them
Conscientiousness The extent to which a person is careful,
scrupulous, and persevering
The constituent aspects of
the Big Five factors
Neuroticism
Neuroticism
• Experience negative
affects (fear, sadness,
guilt, embarrassment,
anger, disgust)
• Susceptibility to
psychological distress
• Cope poorly with
stress
Emotional Stability
• Calm
• Even-tempered
• Relaxed
• Face stressful
situations without
becoming upset/
rattled
The constituent aspects of the Big Five factors
Source: Based on Costa and McCrae (1985)
Aspects of Neuroticism
• Anxiety
• Angry hostility
• Depression
• Self-consciousness
• Impulsiveness
• Vulnerability
Based on NEO-PI-R by Costa & McCrae (1992)
Measure of Neuroticism
How accurately does each statement describe
you?
•
•
•
•
•
•
I often find myself worrying about something.
My feelings are hurt rather easily.
Often I get irritated at little annoyances.
I suffer from nervousness
My mood often goes up and down.
I sometimes feel “just miserable” for no good
reason.
9
Extraversion
Extraversion
• Sociable
• Like people
• Like large groups
• Assertive
• Active, like
excitement
• Talkative
• Cheerful
- Absence of Extraversion
• Reserved
• Independent from
other people
• Shy or prefer to be
alone
• Not unhappy, but
not as cheerful as
extraverts
Aspects of Extraversion
• Warmth
• Gregariousness
• Assertiveness
• Activity
• Excitement-seeking
• Positive emotions
Based on NEO-PI-R by Costa & McCrae (1992)
Measure of Extraversion
How accurately does each statement describe
you?
• It is easy for me to become enthusiastic about
things I am doing.
• I often feel happy and satisfied for no particular
reason.
• I live a very interesting life.
• Every day I do some things that are fun.
• I usually find ways to lift up my day.
• Most days I have moments of real fun or joy.
Openness to Experiences
Open to Experiences • Curious
• Experientially richer
lives
• Like new ideas
• Unconventional
values
• Creative
• Experience emotions
Aspects of Openness
• Fantasy
• Aesthetics
• Feelings
• Actions
• Ideas
• Values
Based on NEO-PI-R by Costa & McCrae (1992
Closed to Experiences
• Conventional
• Conservative
• Prefer the familiar
• Not wild about change
• Narrower scope of
interests
Measure of Openness
How accurately does each statement describe
you?
•
•
•
•
•
•
I have a rich vocabulary.
I have difficulty understanding abstract ideas.*
I have a vivid imagination.
I am not interested in abstract ideas.*
I have excellent ideas.
I do not have a good imagination.*
* Reverse coded items
10
Agreeableness
Agreeableness
• Altruistic
• Sympathetic
• Eager to help
• Assumes the same
from others
• Co-operative
Low agreeableness
• Sceptical of other’s
intentions
• Critical
• Self-centred
• Competitive
• Fight for their
interests
Aspects of Agreeableness
• Trust
• Straightforwardness
• Altruism
• Compliance
• Modesty
• Tender-Mindedness
Based on NEO-PI-R by Costa & McCrae (1992
Measure of Agreeableness
How accurately does each statement describe
you?
•
•
•
•
•
•
I am interested in people.
I am not really interested in others.*
I sympathise with others’ feelings.
I insult people. *
I have a soft heart.
I am not interested in other people’s problems.*
Conscientiousness
Conscientiousness • Active in planning,
organising, carrying out
tasks
• Self controlled
• Reliable
• Strong-willed
• Determined
• Workaholic tendency
Low on conscientiousness
• Less exacting in applying
principles
• Not obsessed with their
goals
• Not driven to succeed
• Unmethodical
• Casual, spontaneous
• More hedonistic
* Reverse coded items
Aspects of Conscientiousness
• Competence
• Order
• Dutifulness
• Achievement striving
• Self-discipline
• Deliberation
Based on NEO-PI-R by Costa & McCrae (1992
Measure of Conscientiousness
How accurately does each statement describe
you?
•
•
•
•
•
•
I am always prepared.
I leave my belongings around.*
I pay attention to details.
I make a mess of things.*
I get chores done right away.
I often forget to put things back in their proper
place. *
* Reverse coded items
11
Are Big Five Predictive of Anything?
• Job performance:
– Across jobs: Conscientiousness
– Social interaction: Extraversion
– Training proficiency: Openness
• Leadership:
– Low N, High E, High O, High C
– Aspect level analysis: best overall predictors
were Dominance and Sociability
How does Personality compare to IQ and SES
for predicting important Life Outcomes?
• Occupational attainment:
–
–
–
–
–
–
– Some researchers want more factors
– Others less (e.g. Eysenck’s 3-factors)
• Concept of factor analysis means that there could be
more than one acceptable factor solution for the same
data set.
• Since advent of the Big 5 personality theory and testing
has changed for better
• Personality factors appear to have strong support from
the Personality research community
• Personality factors offer a good account of individual
differences
.29
.42
-.27
.17
.10
.13
• Divorce correlations:
–
–
–
–
Summary of Big Five
• These personality factors have been found be be quite
robust across Western societies
• However, not everyone agrees with 5-factor model
SES:
IQ:
Neuroticism:
Extraversion:
Agreeableness:
Conscientiousness:
SES:
IQ:
Neuroticism:
Conscientiousness
-.08
.21
.19
-.12
Big Five web link
Several Big Five related tests & inventories
Site for educational purposes!
http://www.outofservice.com/
Why not the Big Five: Criticisms
• Assumptions of model used to derive it are bad:
A more critical view on the
Big Five
–
–
–
–
Why not start by using other languages?
Why not included evaluative terms?
Is there anything beyond the Big Five that is interpretable?
Why use only adjectives? Why not nouns?
• Why not let biology be our guide?
• Big 5 is a-theoretical: Why not test a theory?
• Is Big 5 appropriate for describing malfunctioning
personality?
• Why stop at 5?
– What are higher order factors?
– Do lower order factors work better?
12
Different Cultures
Different Cultures
• Big Five sometimes also used in other
languages
• If we did not start with English, what factors
would have emerged?
• But there are others factors that emerge
depending on what is important to the local
culture
• The HEXACO Personality factor solution:
–
–
–
–
China: Traditionalism (specific to China)
Hebrew: Dependability
Filipino: Temperamentalness
Korean: Masculine Emotionality (possessive envy)
Evaluative Terms
– Only English & Czech have 5 solid factors
– Similar set of 6 factors found in German, Dutch,
French, Italian,…
• Honesty/Humility; Emotionality; Extraversion;
Agreeableness; Conscientiousness; Openness
• An emerging idea, but H-factor seems to be mostly
a factor dealing with generic “badness”.
Abnormal Personality
• Allport argued against use of “evaluative terms”
• Can Big Five describe it?
• What happens if they were included?
• MMPI* contains scales and constructs built
around clinical typologies
• Two new factors added on
– Positive valence (outstanding, wonderful, excellent)
– Negative valence (wicked, evil, bad, disgusting)
• Can cause problems with interpretation
– E.g. person claiming to be evil: guilty religious person
or serial killer.
– Obsessive-Compulsive
– Anti-social
• Recent research suggests that abnormal
personality differs from normal personality by a
matter of degree, not quality
• Hence, items can be made more extreme to
match the nature of the behavioural outcomes.
* Minnesota Multiphasic Personality Inventory (MMPI) – frequently used personality test in mental health.
Abnormal Personality
Trait-Situation Controversy
• Almost all personality disorders are related to
elevations in Neuroticism/ Negative Emotionality
• So far we have examined the historical
development of trait theory from Allport onwards
• Adding extreme traits can describe disorders,
such as…
– Obsessive-Compulsive
– Extreme Conscientiousness
– Example items:
• “I keep my house clean” becomes “I keep my house perfectly
clean”
• “I show up on time” becomes “I always show up on time”
• No evidence that clinical tests perform any better
at distinguishing abnormal personality
• One important notion in trait theory is that
personality is consistent and stable
– an explicit or implicit assumption of trait theorists
• This was also similar to psychodynamic
approaches, (esp. the Freudian model, which also
proposed that personality was stable)
13
Trait-Situation Controversy
• People like Allport, Eysenck, Cattell, Costa and
McCrae are well respected researchers
– and so were their theoretical points of view.
• But question arose whether situation could
override personality variables and affect
behaviour.
• Mainly due to arrival of behaviouristic models
(e.g. Skinner).
• Skinner argued that personality was essentially
the product of history of reinforcement.
References
• Castillo, R. N. (2009). The Trait / Disposition Approach.
Lecture notes.
• Chamorro-Premuzic, T. (2008). Personality and
Individual Differences. BPS Blackwell
• Chamorro-Premuzic, T. & Furnham, A. (2004). A
possible model to understand the personality-intelligence
interface. British Journal of Psychology, 95, 249-264.
• Maltby, J., Day, L., & Macaskill, A. (2006). Personality,
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