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Individual Differences and Personality
Designed for upper level undergraduate and graduate level students inquiring about the psychology of personality and individual differences, this textbook focuses on the personality traits and related characteristics that make each person unique. Basic principles of personality measurement are explained and crucial scientific questions of personality psychology are examined via a reader-friendly style and various boxes of interesting asides to keep students’ attention.Unlike lower-level texts written from a historical perspective that concentrate solely on theory, this textbook summarizes and integrates the contemporary research available about individual differences.
300 pages, Hardcover
First published July 1, 2007
17 people are currently reading
164 people want to read
About the author
Michael C. Ashton
2 books6 followersMichael C. Ashton is a professor of psychology at Brock University in St. Catharines, Ontario. He received his Ph.D. from the University of Western Ontario. He is the author of the textbook Individual Differences and Personality and of many scientific articles in personality psychology.
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Displaying 1 - 5 of 5 reviews
May 22, 2022
3rd edition, 2018
This book explains what actual science knows about individual differences in personality.
When it comes to people's personalities, there's an impressive amount of misinformation and pseudoscience pretty much everywhere around us, so reading this is a must.
The most in-depth sections are the first ones dedicated to methodology, the ones dedicated to the Big5 & HEXACO models of personality, and the one dedicated to mental ability. Not by chance: both the Big5/HEXACO model and the tests to measure mental ability are the areas with the largest amount of accumulated empirical evidence in terms of validity and predictive value.
Topics discussed:
Methodology, factor analysis, models of personality traits, the Big5 & HEXACO model, stability of traits across the life span, biological bases of personality (neurotransmitters, brain structure, hormones), genetic vs. environmental influences on personality, evolutionary insights, cross-generational and cross-national differences, personality disorders, personality and life outcomes (job performance, health, life satisfaction, differences in couples and among friends), mental ability, vocational interests, differences in religiosity and political views, differences in sexuality.
This book explains what actual science knows about individual differences in personality.
When it comes to people's personalities, there's an impressive amount of misinformation and pseudoscience pretty much everywhere around us, so reading this is a must.
The most in-depth sections are the first ones dedicated to methodology, the ones dedicated to the Big5 & HEXACO models of personality, and the one dedicated to mental ability. Not by chance: both the Big5/HEXACO model and the tests to measure mental ability are the areas with the largest amount of accumulated empirical evidence in terms of validity and predictive value.
Topics discussed:
Methodology, factor analysis, models of personality traits, the Big5 & HEXACO model, stability of traits across the life span, biological bases of personality (neurotransmitters, brain structure, hormones), genetic vs. environmental influences on personality, evolutionary insights, cross-generational and cross-national differences, personality disorders, personality and life outcomes (job performance, health, life satisfaction, differences in couples and among friends), mental ability, vocational interests, differences in religiosity and political views, differences in sexuality.
August 16, 2023
Update 2023: This review is of the 1st edition (2007), with an addendum for the 2nd. The current edition is the 4th (2022).
This is the best introduction to the scientific study of personality that I remember seeing. Although the blurb on the cover presents it as “intended for upper level undergraduate and graduate courses in personality and individual differences”, it does not seem to me beyond the grasp of an intelligent fourteen-year-old. It is well organised, systematic, clear, concise, and panoramic in that it discusses the spectrum of scientific theories on its subject, and not merely the author’s favourite ones. Conversely, unscientific theories are eliminated, with Freud and Adler getting merely one passing mention each. Contents:
Chapter 1 — Basic concepts in Psychological Measurement
Basic statistical ideas are discussed, such as reliability and validity, standard scores, normal distribution, correlation coefficient, self-reports, observer reports and biodata.
Chapter 2 — Personality Traits and Inventories that measure them.
The nature of traits is discussed along with strategies for measuring them (empirical/factor analytic/rational). The following personality inventories are briefly described:
- CPI
- Hogan
- 16PF
- Eysenck
- Myers-Briggs
- TCI
- MPQ
- Jackson
- NPQ
- Big Five
- NEO
- HEXACO
- IPIP
The Rorschach is also discussed and its limitation described.
Chapter 3 — Personality Structure: Classifying Traits
The topic of how to achieve complete description without redundancy (i.e. orthogonality of dimensions) is addressed, and a gentle introduction to factor analysis is presented. The lexical approach to finding personality factors is described, with more information on the Big Five and HEXACO inventories.
Chapter 4 — Developmental Change and Stability of Personality
Here we have a good summary of available data on how personality characteristics change through the lifespan.
Chapter 5 — Biological bases of Personality
Early ideas, the Four Humours, Physique and Personality, Cloninger’s theory, Gray’s theory, Eysenck’s theory, comparison of Gray & Eysenck and the relevant empirical evidence, Zuckerman’s model, effect of various hormones.
Chapter 6 — Genetic and Environmental Influences on Personality
I was glad to see that this section stuck to the science and didn’t succumb to political correctness, going carefully through the consequences of twin and adoptive studies, distinguishing between additive and nonadditive heredity and so forth. Assortative mating and birth order are also touched on.
Chapter 7 — The Evolutionary Function of Personality
Under the rubric of Why We Are Not All the Same, here we have material effectively taken from Evolutionary Biology: the concept of evolution by natural selection, fluctuating optimum and frequency dependence, adaptive trade-offs, and some examples. There are also notes on cross-generational and cross-national personality differences, and animal personality.
Chapter 8 — Personality Disorders
The idea of a personality disorder, and various kinds:
- The DSM-IV Disorders (schizoid, schizotypal, paranoid, antisocial, borderline, histrionic, narcissistic*, avoidant, dependent & obsessive-compulsive)
- DSM-IV clusters
- Disorders not included in the DSM-IV (depressive, passive aggressive, self-defeating, sadistic, ADHD, separation anxiety, oppositional defiant, phobias)
- Problems with the concept of personality disorders
- Alternative systems of diagnosis
- Origins & biological bases
*including a brief note explaining for the uninformed who Narcissus was!
Chapter 9 — Personality and Life Outcomes
- Relationships and Marriage (are spouses similar, satisfaction, attachment styles, parenting styles)
- Peer relationships: friendship and status
- Health-related outcomes (substance use, longevity, heart disease)
- Academic performance
- Job performance
- Criminality (self- control, psychopathy)
- Life satisfaction
Chapter 10 — Mental Ability
- The structure of mental ability (one dimension or many?)
- Developmental change and stability in mental abilities
- Biological bases of mental ability
- Genetic and environmental influences
- Mental ability and life outcomes
- Not all g-loaded tasks are the same (fluid & crystallised intelligence, Flynn effect, numerical v. verbal reasoning)
- Alternative ideas about mental abilities (Gardner, Sternberg, Goleman etc.)
- Emotional intelligence
I was most impressed by the way this section sorted out the wheat from the flood of chaff this subject has generated in recent years. Particularly clear are the sections on the oft-misunderstood complementarity of the contributions of Spearman and Thurstone
Chapter 11 — Religion and Politics
- Is religion a personality characteristic?
- Religiosity and the major dimensions of personality
- Developmental change and stability in religiosity
- Religiosity and paranormal beliefs
- Religiosity and life outcomes
- Right-wing authoritarianism
- Social dominance orientation
- Relations between authoritarianism & dominance orientation
- Two dimensions of political attitudes
- Political attitudes and the major dimensions of personality
- Political attitudes, social values and religion
- Developmental change and stability in political attitudes
- Origins of religious beliefs and political attitudes (biological bases, genetic & environmental influences, evolutionary functions)
Chapter 12 — Sexuality
- Major dimensions of sexuality
- Sexuality & Personality (arousal, commitment & orientation)
- Origins of variation (genetic & environmental influences, biological bases, & evolution)
- Sexual orientation
- Sexual arousal
Final Chapter — Conclusions
- What we have learned so far
- What we have yet to learn
- Final Remarks
References
Index
--------------------
Summary
The above outline of course only gives a taste of the diverse information included in this book. I feel that it does a remarkable job of accurately compressing so much information and providing a springboard for further reading, while maintaining readability (although perhaps the references could have been a little more comprehensive), and I thoroughly recommend it.
Update
There is now a 2nd edition. The author was kind enough, in answer to my enquiry, to summarise the revisions. I reproduce his comments (with his permission) below.
----------
There’s a new chapter on Vocational Interests. It’s one of the shorter chapters and has a somewhat more practical emphasis than most of the others do, but it gives much more coverage to this topic than was given in the 1st edition.
The chapter on Personality Disorders is about half rewritten*, to coincide with the reconceptualization in the forthcoming DSM5. (I think the DSM5 framework is an improvement, and it makes the structure of the chapter simpler than it previously had been.)
The descriptions of several of the more "technical" issues (especially reliability and validity in Chapter 2, and heritability studies in Chapter 6) are being somewhat streamlined and reorganized, and thereby (I think) clarified and improved.
Throughout the book there are several new boxes and subsections and paragraphs to incorporate new research findings from the past six years, including some topics not really covered in the 1st edition (e.g., the (non-)existence of personality "types"; rater biases in self- and observer reports; personality similarity in friends; "games" as illustrations of frequency-dependent selection), and some topics where new findings have emerged (e.g., IQ and birth order; heritability of sexual orientation; personality stability between childhood and adulthood).
I would think that the overall scale of revisions is somewhat larger than in the usual "next edition" of a textbook, but the basic structure and content of the 1st edition will remain, so it isn’t a radically new book.
*What happened was that the DSM5 people decided at the last minute to abandon their new system for personality disorder diagnosis; instead it’s being included only as an appendix within the DSM5. I’m still giving that new system a lot of space in the book (because I think it makes more sense), but I’m now keeping some description of the old system simply because it’s still the one that clinicians will be using.
This is the best introduction to the scientific study of personality that I remember seeing. Although the blurb on the cover presents it as “intended for upper level undergraduate and graduate courses in personality and individual differences”, it does not seem to me beyond the grasp of an intelligent fourteen-year-old. It is well organised, systematic, clear, concise, and panoramic in that it discusses the spectrum of scientific theories on its subject, and not merely the author’s favourite ones. Conversely, unscientific theories are eliminated, with Freud and Adler getting merely one passing mention each. Contents:
Chapter 1 — Basic concepts in Psychological Measurement
Basic statistical ideas are discussed, such as reliability and validity, standard scores, normal distribution, correlation coefficient, self-reports, observer reports and biodata.
Chapter 2 — Personality Traits and Inventories that measure them.
The nature of traits is discussed along with strategies for measuring them (empirical/factor analytic/rational). The following personality inventories are briefly described:
- CPI
- Hogan
- 16PF
- Eysenck
- Myers-Briggs
- TCI
- MPQ
- Jackson
- NPQ
- Big Five
- NEO
- HEXACO
- IPIP
The Rorschach is also discussed and its limitation described.
Chapter 3 — Personality Structure: Classifying Traits
The topic of how to achieve complete description without redundancy (i.e. orthogonality of dimensions) is addressed, and a gentle introduction to factor analysis is presented. The lexical approach to finding personality factors is described, with more information on the Big Five and HEXACO inventories.
Chapter 4 — Developmental Change and Stability of Personality
Here we have a good summary of available data on how personality characteristics change through the lifespan.
Chapter 5 — Biological bases of Personality
Early ideas, the Four Humours, Physique and Personality, Cloninger’s theory, Gray’s theory, Eysenck’s theory, comparison of Gray & Eysenck and the relevant empirical evidence, Zuckerman’s model, effect of various hormones.
Chapter 6 — Genetic and Environmental Influences on Personality
I was glad to see that this section stuck to the science and didn’t succumb to political correctness, going carefully through the consequences of twin and adoptive studies, distinguishing between additive and nonadditive heredity and so forth. Assortative mating and birth order are also touched on.
Chapter 7 — The Evolutionary Function of Personality
Under the rubric of Why We Are Not All the Same, here we have material effectively taken from Evolutionary Biology: the concept of evolution by natural selection, fluctuating optimum and frequency dependence, adaptive trade-offs, and some examples. There are also notes on cross-generational and cross-national personality differences, and animal personality.
Chapter 8 — Personality Disorders
The idea of a personality disorder, and various kinds:
- The DSM-IV Disorders (schizoid, schizotypal, paranoid, antisocial, borderline, histrionic, narcissistic*, avoidant, dependent & obsessive-compulsive)
- DSM-IV clusters
- Disorders not included in the DSM-IV (depressive, passive aggressive, self-defeating, sadistic, ADHD, separation anxiety, oppositional defiant, phobias)
- Problems with the concept of personality disorders
- Alternative systems of diagnosis
- Origins & biological bases
*including a brief note explaining for the uninformed who Narcissus was!
Chapter 9 — Personality and Life Outcomes
- Relationships and Marriage (are spouses similar, satisfaction, attachment styles, parenting styles)
- Peer relationships: friendship and status
- Health-related outcomes (substance use, longevity, heart disease)
- Academic performance
- Job performance
- Criminality (self- control, psychopathy)
- Life satisfaction
Chapter 10 — Mental Ability
- The structure of mental ability (one dimension or many?)
- Developmental change and stability in mental abilities
- Biological bases of mental ability
- Genetic and environmental influences
- Mental ability and life outcomes
- Not all g-loaded tasks are the same (fluid & crystallised intelligence, Flynn effect, numerical v. verbal reasoning)
- Alternative ideas about mental abilities (Gardner, Sternberg, Goleman etc.)
- Emotional intelligence
I was most impressed by the way this section sorted out the wheat from the flood of chaff this subject has generated in recent years. Particularly clear are the sections on the oft-misunderstood complementarity of the contributions of Spearman and Thurstone
Chapter 11 — Religion and Politics
- Is religion a personality characteristic?
- Religiosity and the major dimensions of personality
- Developmental change and stability in religiosity
- Religiosity and paranormal beliefs
- Religiosity and life outcomes
- Right-wing authoritarianism
- Social dominance orientation
- Relations between authoritarianism & dominance orientation
- Two dimensions of political attitudes
- Political attitudes and the major dimensions of personality
- Political attitudes, social values and religion
- Developmental change and stability in political attitudes
- Origins of religious beliefs and political attitudes (biological bases, genetic & environmental influences, evolutionary functions)
Chapter 12 — Sexuality
- Major dimensions of sexuality
- Sexuality & Personality (arousal, commitment & orientation)
- Origins of variation (genetic & environmental influences, biological bases, & evolution)
- Sexual orientation
- Sexual arousal
Final Chapter — Conclusions
- What we have learned so far
- What we have yet to learn
- Final Remarks
References
Index
--------------------
Summary
The above outline of course only gives a taste of the diverse information included in this book. I feel that it does a remarkable job of accurately compressing so much information and providing a springboard for further reading, while maintaining readability (although perhaps the references could have been a little more comprehensive), and I thoroughly recommend it.
Update
There is now a 2nd edition. The author was kind enough, in answer to my enquiry, to summarise the revisions. I reproduce his comments (with his permission) below.
----------
There’s a new chapter on Vocational Interests. It’s one of the shorter chapters and has a somewhat more practical emphasis than most of the others do, but it gives much more coverage to this topic than was given in the 1st edition.
The chapter on Personality Disorders is about half rewritten*, to coincide with the reconceptualization in the forthcoming DSM5. (I think the DSM5 framework is an improvement, and it makes the structure of the chapter simpler than it previously had been.)
The descriptions of several of the more "technical" issues (especially reliability and validity in Chapter 2, and heritability studies in Chapter 6) are being somewhat streamlined and reorganized, and thereby (I think) clarified and improved.
Throughout the book there are several new boxes and subsections and paragraphs to incorporate new research findings from the past six years, including some topics not really covered in the 1st edition (e.g., the (non-)existence of personality "types"; rater biases in self- and observer reports; personality similarity in friends; "games" as illustrations of frequency-dependent selection), and some topics where new findings have emerged (e.g., IQ and birth order; heritability of sexual orientation; personality stability between childhood and adulthood).
I would think that the overall scale of revisions is somewhat larger than in the usual "next edition" of a textbook, but the basic structure and content of the 1st edition will remain, so it isn’t a radically new book.
*What happened was that the DSM5 people decided at the last minute to abandon their new system for personality disorder diagnosis; instead it’s being included only as an appendix within the DSM5. I’m still giving that new system a lot of space in the book (because I think it makes more sense), but I’m now keeping some description of the old system simply because it’s still the one that clinicians will be using.
June 8, 2024
A un certo punto diventa palesemente un testo che si affida prevalentemente ai risultati e sui modelli propri dell'inventario di personalità HEXACO, ma non lo ritengo decisamente un male.
Da tenere a mente che una certa fetta di evidenze a supporto proviene, comunque, da studi preliminari - seppur con evidenze positive.
Da tenere a mente che una certa fetta di evidenze a supporto proviene, comunque, da studi preliminari - seppur con evidenze positive.
November 10, 2023
A comprehensive overview of psychology research into personality and other factors of individual differences like intelligence, religiosity and political differences. As far as psychology goes, this book covers rather basic material for an undergraduate level, but the main advantages are its scientific rigour, comprehensiveness and readability.
For rigour, it thoroughly grounds all of its content on research studies instead of relying on intuition or popular culture. However, it mentions common beliefs in society to comment on whether they are backed up by science or not, which is very helpful for a general audience.
For comprehensiveness, it describes all the major theories about each psychological topic in an impartial way, though it only goes into detail about the ones that fit the evidence the best. The book's unbiased approach means that it delves deeply into the methods used by each study so the reader can understand how the research is conducted and how valid (or not) the results are. Its coverage of the research also honestly explains the drawbacks and missing parts yet to be investigated.
Another advantage is its readability, as the author took great care to make the text sound interesting, breezy and relatable even when it is covering rather dry statistical results. All of these data are connected with real life situations that are significant and useful for the reader. This is a rarity among textbooks which have a reputation for reading like... well, textbooks.
For me, the main lessons were:
- The personality frameworks and inventories and how they all relate to one another.
- What a "chorion" is and why it matters
- The biological bases (neurotransmitters) of the personality differences.
- The impact of assortativity
- Couples are only mildly similar in personality factors but they are highly similar in religiosity and politics
- High A and low N are correlated with marital satisfaction
- Friends are similar in the H and O factors of personality
- Why the DSM got shifted towards a single "Personality Disorder"
- Why the DSM personality disorders are arranged in three clusters (superficial impressions)
- Whether criminals really have lower IQ on average, or if lower IQ criminals get caught more often than higher IQ criminals (it's the former)
- Career aptitude is stable across one's lifespan and can even be reliably detect at age twelve!
My main criticism: No mention of autism spectrum! I feel like the autistic vs. neurotypical traits would be a dimension (or several) above and beyond the Big Five or HEXACO dimensions. Which of these factors would literal vs. arbitrary speech load onto, for example?
For rigour, it thoroughly grounds all of its content on research studies instead of relying on intuition or popular culture. However, it mentions common beliefs in society to comment on whether they are backed up by science or not, which is very helpful for a general audience.
For comprehensiveness, it describes all the major theories about each psychological topic in an impartial way, though it only goes into detail about the ones that fit the evidence the best. The book's unbiased approach means that it delves deeply into the methods used by each study so the reader can understand how the research is conducted and how valid (or not) the results are. Its coverage of the research also honestly explains the drawbacks and missing parts yet to be investigated.
Another advantage is its readability, as the author took great care to make the text sound interesting, breezy and relatable even when it is covering rather dry statistical results. All of these data are connected with real life situations that are significant and useful for the reader. This is a rarity among textbooks which have a reputation for reading like... well, textbooks.
For me, the main lessons were:
- The personality frameworks and inventories and how they all relate to one another.
- What a "chorion" is and why it matters
- The biological bases (neurotransmitters) of the personality differences.
- The impact of assortativity
- Couples are only mildly similar in personality factors but they are highly similar in religiosity and politics
- High A and low N are correlated with marital satisfaction
- Friends are similar in the H and O factors of personality
- Why the DSM got shifted towards a single "Personality Disorder"
- Why the DSM personality disorders are arranged in three clusters (superficial impressions)
- Whether criminals really have lower IQ on average, or if lower IQ criminals get caught more often than higher IQ criminals (it's the former)
- Career aptitude is stable across one's lifespan and can even be reliably detect at age twelve!
My main criticism: No mention of autism spectrum! I feel like the autistic vs. neurotypical traits would be a dimension (or several) above and beyond the Big Five or HEXACO dimensions. Which of these factors would literal vs. arbitrary speech load onto, for example?
April 20, 2011
Amazing. And I've done a small amount of research assistant work for the author.
Displaying 1 - 5 of 5 reviews