What is personality?
Personality The meaning has changed through history : from “external illusion” to “surface reality” and finally to opaque or veiled inner traits.
Personality It is seen today as a complex pattern of psychological characteristics, largely unconscious and not easily altered, expressing themselves automatically in almost every facet of functioning.
Defining Personality Affective and willingness totality of the individual (instinct, temperament, character) (Bini-Bazzi)
Allport (1937)
No definition of personality could be considered universally accepted….. It depends on the different “personality theory” of reference
Theories about personality development Constitutionalistic Olistic Objectivistic Psychodinamic Perception Relational Phenomenological-existentialist
Theories about personality Constitutionalistic Olistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Theories about personality development Constitutionalistic Olistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Constitutionalistic theory From the ancient greek-roman medicine: Hippocrates - Galen Humoral doctrines: all diseases stemmed from an excess of or imbalance among four bodily humours
Constitutionalistic theory - yellow bile = hearth choleric temperament
Constitutionalistic theory - black bile = water melancholic temperament
Constitutionalistic theory - blood = fire sanguine temperament
Constitutionalistic theory - phlegm = air phlegmatic temperament
Ernst Kretchmer: Four basic physical types pyknic: large thorax and abdomen, soft and poorly muscled limbs, tendency towards obesity
Ernst Kretchmer: Four basic physical types athletic: extensive muscular development, broad skeletal endowment
Ernst Kretchmer: Four basic physical types asthenic: fragile, possessing thin muscularity, frail bone structure
Ernst Kretchmer: Four basic physical types dysplastic: a mixture of the other three variants
Ernst Kretchmer Psychotic disorders are accentuations of normal personality types
William Sheldon: Three basic dimension Endomorphy: predominance of roundness and softness viscerotomia (gregariousnes, easy expression of feeling and emotion, love of confort, avoidance of pain, dependance on social approval)
William Sheldon: Three basic dimension Mesomorphy: muscular and connective tissue dominance somatotomia (assertiveness, physical energy, low anxiety, courage, social callousness, indifference to pain, need for action and power when troubled)
William Sheldon: Three basic dimension Ectomorphy: linearity and fragility of structure cerebrotonia (restraint, self-consciousness, introversion, social awardness, desire for solitude when troubled)
Somatotypes Ectomorph thin frail physique cerebrotonia anxious, neurotic
Somatotypes Endomorph soft, rounded physique relaxed, social easy going depressed, over-indulgent
Somatotypes Mesomorph muscular, strong physique bold, assertive, energetic aggressive, hyperactive, Type A
Theories about personality development Constitutionalistic Holistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Holistic theory K. Goldstein - Is more useful studying an individual completely than an isolated psychical function in many individuals
Holistic theory A. H. Maslow Personality is an integration of basic needs - physiological needs (hunger, thirst)
- security needs (belonging to a group, love)
- cognitive and aesthetic needs
Maslow's Hierarchy of Needs
Key Assumptions inherent striving for self-realization satisfaction of needs leads to growth frustration of needs leads to pathology self-actualization
Self-Actualized People ideal self = perceived (actual) take responsibility for self-change acknowledge imperfections and ordinary feelings like others accept themselves as worthwhile
Self-Actualized People have a deep feeling of kinship with others enjoy solitude as well as companionship are able to focus on problems outside themselves are strongly ethical, creative
Holistic theory P. Lecky Personality is the maintaining of a unified and auto - consistent aspect in an unstable environment, from which the individual accepts the self - coherent values and rejects the others.
Abhidharma….oriental psychology The mind is the start point, the focus point and also, the arrival point Psychopathology is due to a lack of control on the mind-body
Abhidharma….oriental psychology There is no agent separated from the action, no percept separated from perception, no coscient subject separated from conscience Meditation conducts to a sane personality
Theories about personality development Constitutionalistic Holistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Objectivistic theory Russian reflexologic school - I. P. Pavlov
- force (scarce sensibility to peripheric stumuli)
- equilibrium (related to EEG indexes)
- mobility (adaptive capacity)
American behaviourism - J. B. Watson
- habits (cue + response) as fundaments
- drives (instinct and learning) as dynamic factors
Theories about personality development Constitutionalistic Holistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Social learning theory J.B Rotter - personality is the characteristic way to react to an identifiable situation
- potential behaviour (interaction between the individual and the environment)
- expectation of the individual, based on his/her past experiences
- reinforcement strictly connected to motivation
- motivation
Theories about personality development Constitutionalistic Olistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Theories of Personality
Freud’s Psychoanalytic Theory Thoughts and behavior are guided mainly by the unconscious part of the mind. Sexual motivation plays a central role in everyday life. Concept of “infantile sexuality”: erotic experiences in infancy and early childhood shape personality in adulthood.
Freud’s Psychoanalytic Theory Conscious: everything we are aware of at the moment; just the “tip of the iceberg”. Preconscious: memories that we can bring to consciousness. Unconscious: memories, wishes, and instincts (desires) that are too threatening or painful to bring to consciousness.
Psychodynamic Theories
Key Assumptions psychic determinism - all feelings, thoughts, actions have a purpose, are motivated personality is determined by events or actions from early life personality is the interplay of conscious and unconscious conflicts, motives
Key Concepts developmental stages psychodynamic (object) relations defense mechanisms
Structure of the Mind Unconscious: material unavailable to current awareness - motivated forgetting Preconscious: material available to awareness, momentarily out of consciousness - lack of attention Perceptual Conscious: material in current awareness
Windows to the Unconscious dreams humor slips of the tongue
Personality Structure ID: source of libidinal (sexual) and aggressive drives Pleasure Principle: immediate gratification of drives and impulses
Personality Structure EGO: Source of rational choice Reality Principle: search for realistic, balanced gratification of drives
Personality Structure SUPEREGO: Source of “socially correct” choice - “conscience” Morality Principle: demands for “perfect” behavior “always”, regardless of circumstances
Well-Balanced Personality Structure
Antisocial Personality
Compulsive Personality
Depressed, Anxious
Object Relations focus on mental representations of self and others integration of the positive and negative aspects into realistic whole formation of attachments – intimate relations attachment theory
Theories about personality development Constitutionalistic Olistic Objectivistic Social learning Psychodinamic Relational Phenomenological-existentialist
Relational theory (Watzlawick) Personality is a system Personality is distinct by comunication which has not any opposite, because both activity and inactivity (words and silence) are a message, and influence the others, who have to answer to communication by communicating themselves
Theories about personality development Constitutionalistic Olistic Objectivistic Social learning Psychodinamic Relational Phenomenological-existentialist
K. Jaspers Attitude : - Objective
- Autoreflectant
- Enthusiactic
Images of the world - Spatio-sensorial
- Psychic-cultural
- Metafisic
K. Jaspers Throug the same attitudes men communicate to each other and comprehend each other. When attitudes are different, they live, thought, act, near each other without being in touch
Theories about personality Constitutionalistic Olistic Objectivistic Social learning Psychodinamic Perception Relational Phenomenological-existentialist
Factorial theories R.B. Cattell - personality traits
- measure instruments L=biographicinterview
- Q=autovalidation inventory
- T=objective tests 16PF
H.J. Heysenk - dimensions
- types (general factors), traits (group factors), abitual responses, specific responses
Raymond Cattell-History Born 1905 in England World War I led to interest in social issues Initial training in physics and chemistry Worked with Spearman--mathematical emphasis Exposed to factor analysis in the U.S. A key figure in the trait and factor movement during and after World War II
Trait Approach (formal definition) Traits are emotional, cognitive, and behavioral tendencies that constitute underlying personality dimensions
Trait & Factor Assumptions A myriad of human characteristics exist Basically, a smaller sub-set of personality traits can account for human individual differences Traits may be identified both deductively (consistent with an existing theory) or inductively. Different theorists proposed different traits based on their methodological approach (e.g. Jung vs Cattell) Traits vs states (e.g anxiety) There was a “Trait and Factor” era in psychology
How do we measure traits?
Trait Approach One approach would be to generate labels for oneself (e.g., honest, dishonest).
Trait Approach What is the major problem with this approach?
Trait Approach There are over 18,000 words in Webster’s dictionary that can be used to describe an individual. Many of these words however denote similar characteristics
Trait Approach Cattell (1957) - reduced the majority of these words to a list of 16 traits (e.g., warm, emotionally stable, intelligent…)
Trait Approach factor analysis (a statistical technique used to identify underlying dimensions) given a list of items determine which item(s) is related to which item(s)
Assumptions of Factor Analysis An inductive method - Exploratory vs confirmatory factor analysis
Founded on quantitative observations A data reduction approach - Simplify original data
- Identify relationships (factors)
Limited by the extent of original data and the number of individual cases included - A common bias in FA studies
Methods of Factor Analysis Quantification of a broad range of data - Convergent and divergent
- Multiple methods
Based on correlation and matrix algebra Factor loading (principle components analysis) Factor rotation (orthogonal - varimax - and oblique) Factor interpretation (qualitative) Pre-computer computations were Herculean
Cattell’s Approach Source vs surface traits Extensive quantitative data (L, Q, & T data) - Avoid method error variance
Oblique factor rotation (factor inter-correlation) 16 PF Scale Cattell believed that he had found all of the important personality traits
Cattell’s Trait Categories 23 Normal Primary Source Traits 12 Abnormal Primary Source Traits 8 Second order Source Traits - Factor analysis of factor analysis
Cattell’s Dynamic Trait Theory Attitudes: a desire to act in response to a situation. Ergs: 10 innate drives or motives Sems: social acquired attitudes (learned) Dynamic - Inter-relation of attitudes, ergs, and seems
- Used to explain and predict behavior..
Cattell’s 16 PF Cattell’s 16 PF 16 basic behavior clusters position on continua, creates profile relaxed – tense; trusting – suspicious; practical – imaginative; submissive – dominant; timid – venturesome
Hans Eysenk-History Born 1916 in Germany Went to England to escape the Nazi’s Accidentally entered psychology Influenced by psychometrically oriented teachers (Spearman) Study of the effectiveness of psychotherapy
Eysenk’s Approach Hypothetic-deductive: pre-analysis theorizing Genetic-biological emphasis Traits are “important semi-permanent personality dispositions.” Focus on Types or derived factors--aiming for maximum simplicity
Eysenk’s Factors Factor characteristics - Bi-polar factors
- Normally distributed
Extraversion-Introversion Neuroticism-Stability Psychoticism-Superego function
Evaluation of Trait & Factor Theories Generated much research Precise and testable Moderately falsifiable Applied value (16 PF and MPI) Research validity Parsimony
Trait Approach (Five Factor Model) A good acronym to use in remembering these five factors is: - O - openness
- C - conscientiousness
- E - extroversion
- A - agreeableness
- N - neuroticism
Big Five Big Five 5 higher order factors OCEAN – openness, conscientiousness, extraversion, agreeableness, neuroticism Really Big 2 extraversion – introversion stability – instability
Trait Approach (Five Factor Model) Can anyone see a potential problem with this research? Hint: On what has this work been based?
Trait Approach (Five Factor Model) The potential problem pertains to whether these traits are cross-culturally universal?
Trait Approach (Five Factor Model) McCrae and colleagues (1997, 1998) these five factors do appear to be similar across cultures
Trait Approach (Five Factor Model) when words are translated the five traits appear when words from the native language are used the five traits do not always hold up e.g., Chinese - only three of the five factors appeared
Trait Approach (advantages) Traits are measurable Develop more objective personality tests - MMPI (Minnesota Multiphasic Personality Inventory)
Two methods to approach the study of personality: Two methods to approach the study of personality: - NOMOTHETIC or CONSTRUCT CENTERED (Alport,1937)
- IDIOGRAPHIC
Nomothetic approach Is concerned with personality in an abstract sense not with any one individual. The emphasis is on discovering how certain constructs relate or coher with others, and why.
Personality is an integrated phenomenon: Needs motives mechanisms traits schemas defenses
Personality is described in terms of deviation of individual scores from the group mean…... The combination of various levels of individual difference variables constitutes individuality. Numerous scales representing a selection of personality traits are factor analized for “latent” pattern of covariation. The larger factors are taken as fundamental dimensions of personality.
Advantages Looking at personality in the abstract, not being grounded to any one person. “genuinely scientific enterprise”. single, measurable and comparable phenomena.
Idiographic approach Enphasizes individuality, complexity and uniqueness of each person individuality is the result of a unique history of trans-action between biological, (temperament and genetic constitution) and contextual factors
“The history of personality is personality” (Murray, 1938) Not only a cross-sectional description but also an elucidation of the specific develomental constraints - possibilities
- experiences
- free will
- chance
Is personality a persistent feature?
Personality: relationship to Axis I disorders
All these models.. ..are possible and likely to be true for different individuals In fact it is not impossible that all are applicabile within a single individual to some degree
Approaches to classification of PD Categorical models Traits Dimensional models EPQ, Cattell Prototypal model DSM III, IV etc…
Empirical issues Are clinical syndromes discrete entities? Can they be clearly separated? Is personality consistent? Behaviours over time and situations rarely achieve correlations beyond the 0.30 level, the so called “personality coefficient” (Mischel, 1979)
Genetics What is the matter with personality?
Demonstrating Genetic Influence in the Past Pedigree Analysis Twin Studies Adoption Studies
Demonstrating Genetic Influence in the Future Direct DNA analysis of affected individuals Gene rescue
Overview What is a Gene? How Genes Influence Behavior? Research
Charles Darwin’s On the Origins of the Species, 1859 Species undergo gradual orderly change - fossil record
- structural similarities among existing species
- programs of selective breeding
- observations of evolution in progress
- Darwin proposed mechanism of natural selection
Mendelian Genetics Gregor Mendel was simultaneously studying dichotomous traits in true breeding lines - genes
- alleles
- dominant/recessive
- genotype/phenotype
- homozygous/heterozygous
Genes Deoxyribonucleic Acid (DNA) Double-Helical Structure discovered 1953 Transcription to proteins
How Genes Work DNA is made of nucleotides (A,T,C,G) Pattern of nucleotides determines amino acid ID String of amino acids form protein Proteins constrain structure and function of organism (interacting with the environment) Only about 1-1.5% is coded DNA, other 99% is poorly understood but regulates coding
How genes influence phenotype Genes rarely cause phenotype - quantitative effects are more common
Genes determine the range of possible responses to the environment Genes always interact with environment to determine outcome - e.g., environment can turn on/off gene transcription
Hunt for genetic influence Phenotype Gene (one gene at a time) Gene Phenotype (now possible) * non-coding (regulatory) DNA may also influence phenotype. I.e., nicotine addiction and neuroticism with regulation of serotonin (HTTLPR)
Single Gene vs. Oligogenic traits Qualitative vs. Quantitative traits Mendelian traits/diseases are relatively rare - Sickle cell anemia is caused by a single point mutation (A to T) in one of the genes that specifies hemoglobin protein of red blood cells.
Most diseases, like heart disease, obesity or schizophrenia are thought to be polygenic - still important to identify particular influences
Technological Advances Human Genome project - consensus sequence June, 2000
Identification of polymorphic DNA - Single nucleotide polymorphisms (snps)
- variations from consensus sequence in at least 1%
- information about disease susceptibility
- information about early human migrations
- approximately 2,500,000 such variations contribute to differences in phenotype
Genes, Environment & Personality
Behavioral Genetics (BG) Interested in Determining Source of Individual Differences - Genetic Influences (G)
- Environmental Influences (E)
- Interactions Between G and E
Is Behavioral Genetics “Deterministic”? “Influence” versus “Determine” Rarely is behavior "completely" genetic Genetic influence does not preclude environmental intervention. Role of Environment is extremely profound / important
Genotype: Genetic makeup of the individual. Identical Twins Share Same Genotype Siblings share ½ their genotype Parents and biological children share ½ their genotype.
Phenotype: Any Measurable, Observable Characteristic (Examples:) - Specific Behaviors
- IQ (Note Difference between IQ and “Intelligence”)
- Disorders (or symptoms)
- Height, Weight, Hair Color
- Personality Traits
Environment: Includes pre-natal influences - Shared Environment: Environmental Effects shared by family members
- Physical Structure of Home
- Parental Discipline Style???
- Non-shared Environment: Environmental. Effects unique to the individual -- NOT shared by family members.
- Illnesses
- Peers
- Differing Perceptions???
Single Gene Explanations of Complex Behaviors are Unlikely to be Correct Most Complex Characteristics Influenced by Multiple Genes - Intelligence / IQ
- Personality
- Behaviors above usually normally distributed in population
How are Genetic Influences Investigated?
Family Studies
Adoption Studies
Monozygotic Twins Monozygotic Twins 100% genetic overlap Dizygotic Twins 50% genetic overlap Concordance rate of traits similarity of the twin pair – both high, both low
married women named Linda & Betty married women named Linda & Betty named sons James Allan chain smoked Salems drove Chevrolets had workshops in the basement, enjoyed carpentry had a minor heart attack gained and lost 10 pounds
had Ph.D’s and were university professors had Ph.D’s and were university professors drove VWs had brothers named John jogged and played racquetball gourmet cooks and had same cookbooks used same deodorant, make-up, toothpaste stored rubber bands on cupboard handles got married and divorced in same years read many of the same magazines/ books lived in Oklahoma and Chicago ordered same clothes from LL Bean had 3 identical pairs of Bass shoes
Minnesota reunited twin studies Minnesota reunited twin studies MZ twins - 100% genetic overlap DZ twins - 50% genetic overlap compared concordance when reared together or reared apart heritability = 0.39 - 0.58 on a wide range of traits
Twin Study Method Twins Differ with respect to genetic relatedness - MZ (Identical) Twins Share 100% of Genes
- DZ (Fraternal) Twins Share 50% of Genes
MZ and DZ Twins are equal with respect to shared environment If MZs more similar than DZs, infer genetic influence
Special Case: Identical Twins Reared Apart (MZA)
Big 5 Trait Descriptors (OCEAN) Openness to experience: curiosity, flexibility, unconventional attitudes Conscientiousness: diligent, disciplined, well-organized, dependable Extraversion: outgoing, sociable, upbeat, assertive Agreeableness: sympathetic, trusting, cooperative, straightforward Neuroticism (anxiousness): anxious, irritable, self-conscious..
Extraversion – 5 Twin Studies Britain US Swe. Austral. Finl. Men MZ .65 .57 .47 .50 .46 DZ .25 .20 .20 .13 .15 Women MZ .46 .62 .54 .53 .49 DZ .18 .28 .21 .19 .14
The Brain Brain reaches its maximum number of synaptic connections and its greatest metabolic activity around age 3 or 4
Brain Hemispheric Hypothesis Left side of Brain-Role in Positive Emotions-Creative side of Brain Right side of Brain-Role in Negative Emotions-Methodological, systematic side of Brain
Messages from Brain Travel by Nervous System The Central Nervous System is the Communications Highway of the body Brings help to the body based on the messages it screens from the environment
Neurons where the messages are delivered! Bio-chemical electrical impulses create a cascade of effects based on the message sent to various organ receptors of the body
Neurotransmitters Impacted Too! Not only are there physiological changes but there is altering of neurotransmitters based on messages from brain Absence or overabundance can create whole new set of consequences
Neurotransmitters Brain = Billions of Brain Cells-Neurons Neurons transmit information – electrical conduction within nerve cells & between nerve cells Message once carried through body cell (Axon) crosses space –Synapse to receiving cell
Types of Neurotransmitters Dopamine-dopaminergic system Norepinephrine-noradrenergic system Serotonin-serotonergic system Control senses, thinking, perception, mood, attention, and behavior Unfortunately at this time we can not measure amount for baseline therapeutic levels
Dopamine Receptors and Personality Traits
“Novelty Seeking” Gene
D4 Dopamine Receptor Gene
Potential susceptibility genes Novelty Seeking Ebstein et al (1996) Dopamine D4 receptor (D4DR) exon III polymorphism associated with the human personality trait of Novelty Seeking. Nat Genet 12:78-80. Association between NS and the 7 repeat allele in the locus for DRD4 (11p15.5) in a group of 124 unrelated Israeli normal subjects. NS was assessed from the Tridimensional Personality Questionnaire (TPQ) (Cloninger et al., 1987).
Potential susceptibility genes Novelty Seeking Benjamin et al (1996) Population and familial association between the D4 dopamine receptor gene and measures of Novelty Seeking. Nat Genet 12:81-84. Association between NS and long alleles of DRD4 gene in 315 subjects, mostly male siblings from United States. This study utilized the NEO Personality Inventory (NEO-PI-R)(Costa and McCrae, 1992) from which TPQ NS scores can be estimated.
Potential susceptibility genes Novelty Seeking Ebstein, R. P., et al., 1996. Dopamine D4 receptor (D4DR) exon III polymorphism associated with the human personality trait of Novelty Seeking. Nat Genet 12, 78-80. Ebstein, R. P., et al., 1997. 5-HT2C (HTR2C) serotonin receptor gene polymorphism associated with the human personality trait of reward dependence: interaction with dopamine D4 receptor (D4DR) and dopamine D3 receptor (D3DR) polymorphisms. Am J Med Gen 74, 65-72. Jonsson, E. G., et al., 1997. Lack of evidence for allelic association between personality traits and the dopamine D4 receptor gene polymorphisms. Am J Psychiatry 154, 697-9. Ono, Y., et al., 1997. Association between dopamine D4 receptor (D4DR) exon III polymorphism and novelty seeking in Japanese subjects. Am J Med Gen 74, 501-3. Sander, T., et al., 1997. Dopamine D4 receptor exon III alleles and variation of novelty seeking in alcoholics. Am J Med Gen 74, 483-7. Vandenbergh, D. J., et al., 1997. No association between novelty seeking and dopamine D4 receptor (D4DR) exon III seven repeat alleles in Baltimore Longitudinal Study of Aging participants. Mol Psychiatry 2, 417-9. Jonsson, E. G., et al., 1998. Lack of Association Between Dopamine D4 Receptor Gene and Personality Traits. Psychol Med 28, 985-989. Noble, E. P., et al., 1998. D2 and D4 dopamine receptor polymorphisms and personality. Am J Med Gen 81, 257-67. Staner, L., et al., 1998. Association between Novelty-seeking and the Dopamine D3 receptor gene in bipolar patients - A preliminary report. Am J Med Gen 81, 192-194. Auerbach, J., et al., 1999. Dopamine D4 receptor (D4DR) and serotonin transporter promoter (5-HTTLPR) polymorphisms in the determination of temperament in 2-month-old infants. Mol Psychiatry 4, 369-373. Bau, C. H., et al., 1999. Dopamine D4 receptor gene and personality dimensions in Brazilian male alcoholics. Psych Genet 9, 139-43. Kuhn, K. U., et al., 1999. Allelic variants of dopamine receptor D4 (DRD4) and serotonin receptor 5HT2c (HTR2c) and temperament factors: Replication tests. Am J Med Gen 88, 168-172. Paterson, A. D., et al., 1999. Dopamine D4 receptor gene: novelty or nonsense? Neuropsychopharmacology 21, 3-16. Benjamin, J., et al., 2000. Association between tridimensional personality questionnaire (TPQ) traits and three functional polymorphisms: dopamine receptor D4 (DRD4), serotonin transporter promoter region (5-HTTLPR) and catechol O-methyltransferase (COMT). Mol Psychiatry 5, 96-100. Kotler, M., et al., 2000. Failure to replicate an excess of the long dopamine D4 exon III repeat polymorphism in ADHD in a family-based study. Am J Med Gen 96, 278-281.
Molecular Genetic Studies Ebstein 1996 DRD4 TCI Novelty Seeking Benjamin 1996 DRD4 NEO Novelty Seeking Compton 1996 DRD2 TCI NS In cocaine abusers Ebstein 1997 DRD3, HTR2C,DRD4 TPQ RD and P Sullivan 1998 DRD4 TCI NS negative Staner 1998 DRD3 TPQ NS in bipolar subjects Ekelund 1999 DRD4 TCI Novelty seeking Strobel 1999 DRD4 TPQ novelty seeking Hill 1999 DRD2 and DRD4 MPQ Affective Dimension Kuhn 1999 DRD4 and 5HTT TPQ NS and RD (DRD4) Ekelund 1999 DRD4 TCI Novelty Seeking Persson 2000 DRD4 NEO NS negative Comings 2000 DRD4 TCI self trascendence Lusher 2001 DRD4 TCI NS in substance ab. Suhara 2001 DRD2 (PET study) TCI NS and DRD2 binding
Molecular Genetic Studies Herbst 2000 DRD4 and 5HTT TCI NS and HA negative Persson 2000 DRD4 NEO Extroversion negative Tsai 2001 alpha1a NaR TPQ Reward dependence Mitsuyasu 2001 DRD4 TCI Reward dependence Ronai 2001 DRD4 TCI Novelty Seeking Kusumi 2002 5HT2A TCI negative all dim. Bookman 2002 DRD4 NEO Extroversion Jonsson 2002 DRD4 TCI NS negative Okujama 2002 DRD4 TCI NS in Japanese Tsai 2002 5HTT TPQ Harm Avoidance Tsai 2002 NaT TPQ Reward Dependence
Anxiety-related traits short variant of the serotonin transporter gene (5-HTT or SERT)
An integrative perspective - Both the nomothetic and idiographic perspectives are unsatisfying
- Individuals cannot be made so individual that they become ineffable
- The individual is a singular phenomenon only partially accessible to science and its methods
- We are called on not merely to record behaviour in this or that domain, but to explain it
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