Eysenck's PEN model and Gray's RST model

Question 1

what three personality domains make up Eysenck’s PEN theory?

Answer 1

• Psychoticism (P)
• Extraversion (E)
• Neuroticism (N)

Question 2

what does Eyseneck’s PEN theory assume?

Answer 2

• These domains are used to describe the entire population (not just clinical)
• The theory also assumes that the domains are orthogonal (i.e., statistical independence) = Being highly extraverted does not make you more or less neurotic

Question 3

what are the four sources of support for Eysenck’s PEN theory?

Answer 3

1. Psychometric evidence
2. biological basis
3. theoretically plausible
4. predictive of social issues

Question 4

how did Eysenck describe an introvert?

Answer 4

Prefer to spend time alone and predictable contexts and are quiet and well-ordered

Question 5

how did Eysenck describe an extravert?

Answer 5

Prefer excitement and stimulation, the company of others, are talkative, outgoing and externally driven, and like parties and friends

Question 6

how did Eysenck describe someone who is neurotic?

Answer 6

Emotionally unstable, anxious, fearful, tense, moody, irritable, depressed, poor sleep, slow to return to ‘even keel’ after stressful event

Question 7

how did Eysenck describe someone who is emotionally stable?

Answer 7

Even-tempered, quick to return to equilibrium after stressful event, calm, slow to react emotionally

Question 8

how did Eysenck describe someone who is a psychopath?

Answer 8

Aggressive, cold, and lack empathy (all negative facets, except creativity)

Question 9

how did Eysenck describe someone who is sociable?

Answer 9

Unselfish, sympathetic, cooperative, and conventional

Question 10

what is the key assumption of the biological basis of PEN?

Answer 10

Personality traits reflect individual differences in brain structure / function

Question 10

what brain regions are associated with Eysenck’s PEN theory?

Answer 10

• Reticular Formation (Networks of nuclei located in the brainstem) and ARAS (ascending pathways to cortex)
• cortex (outermost layer of the brain)
• Limbic system (deep brain structure inc. hippocampus and amygdala

Question 11

How does the limbic system relate to neuroticism?

Answer 11

controls response to emotional stimuli. This system is more aroused in neurotic individuals when facing emotion-inducing stimulation

Question 12

How does the Reticulo-cortical circuit relate extraversion?

Answer 12

controls the cortical arousal generated by incoming stimuli. The system is more aroused in introverts than extraverts

Question 13

how does the Ascending Reticular Activating System (ARAS) relate to extraversion?

Answer 13

• ARAS acts as a gate and controls the overall level of arousal in the cortex
• People low in extraversion (i.e., introverts) display higher levels of activity in the ARAS (i.e., too much arousal is let in), which causes them to seek situations with low stimulation
• People high in extraversion display lower levels of activity in the ARAS (i.e., too little arousal is let in), which causes them to seek situations with high stimulation

Question 14

what is the relationship between performance and arousal?

Answer 14

• Performance improves as arousal increases, but it deteriorates when arousal levels become too high
• Arousal therefore has an optimal level, which can be different for different tasks and for different people

Question 15

how does the limbic system relate to neuroticism?

Answer 15

• The limbic system regulates the sympathetic nervous system (SNS) which is part of the autonomic nervous system (ANS) that produces involuntary responses.
• The SNS is in charge of the body’s “Fight or Flight” response to threatening situations, but also remains constantly active at a basic level to maintain homeostasis.
• According to Eysenck, people high in neuroticism display hypersensitivity in the SNS, which causes them to react more strongly to potentially threatening situations.
• Increased activation of the limbic system is then needed to regulate their response.

Question 16

what brain areas explain neuroticism?

Answer 16

• In the original model: Underspecified biological basis, possibly related to regulation of serotonin or dopamine. Might also be related to sex hormones
• In recent decades: The amygdala as a key component in predominant models of psychopathy

Question 17

Questionnaires to measure Eysenck’s PEN theory in people?

Answer 17

• Several versions have appeared: EPI, EPQ, EPQ-R, Short-Scale EPQ-R
• The Short-Scale EPQ-R consists of 48 questions that have to be answered with simple yes-or-no responses (Eysenck, Eysenck & Barrett, 1985):
  1. Does your mood often go up and down? (N)
  2. Do you take much notice of what people think? (P)
  3. Are you a talkative person? (E)
  Besides 12 items for each domain, the questionnaire also has a scale (called Lie) with 12 items which measure whether the questionnaire has been answered truthfully (i.e., social desirability)
  4. If you say you will do something, do you always keep your promise no matter how inconvenient it might be? (L)

Question 18

what did Eysenck find from his questionnaire?

Answer 18

• Within scales: Eysenck et al. (1985) reported “good” internal consistency for Extraversion (α = ~.85) and Neuroticism (α = ~.85) but “questionable” internal consistency for Psychoticism (α = ~.6).
• Between scales: The three scales were orthogonal: did not correlate with each other (rs ≤ .14)

Question 19

what is Gray’s Reinforcement Sensitivity Theory (RST)

Answer 19

Instead of describing personality traits in terms of arousal and reactivity to situations and stimuli (as in Eysenck’s theory), Gray argued that differences in personality stem from the extent to which people respond to rewards and punishment.
- Gray through the PEN model lacked support

Question 20

Key principles of Gray’s Reinforcement Sensitivity Theory (RST)

Answer 20

• Some people are highly sensitive to positive reinforcements and tend to seek rewards and positive experiences → They will learn faster when they are offered pleasant stimuli
• Some people are highly sensitive to negative reinforcements and tend to avoid punishment and negative experiences → They will learn faster when there are aversive stimuli

Question 21

what are the biological components of Gray’s RST theory?

Answer 21

1. Behavioural Activation System (BAS)
   Sensitivity to rewards and pleasant stimuli
   Approach and Impulsivity
   Dopamine
2. Behavioural Inhibition System (BIS)
   Sensitivity to punishment and aversive stimuli
   Avoidance and Anxiety
   Norandrenaline and serotonin
3. Fight-Flight System (FFS) – (added later and role revised over time)
   Unconditioned Responses and Fear

Question 22

what are the three subscales of BAS in Gray’s RST?

Answer 22

1. reward responsiveness, e.g. when I get something I want, I feel excited and energised
2. Drive, e.g. I go out of my way ti get the things I wast
3. Fun seeking, e.g. I crave excitement and new sensations

Question 23

what revisions were made to Gray’s RST by Gray and McNaughton (2000)

Answer 23

The three systems were modified:
1. Behavioural Activation System (BAS) Largely unchanged from original model.Sensitive to conditioned and unconditioned responses to reward
2. Fight-Flight-Freeze System (FFFS) Global avoidance and escape system in threatening situations. Sensitive to conditioned and unconditioned stimuli. Associated with fear
3. Behavioural Inhibition System (BIS) Conflict resolution between FFFS and BAS. Emotion – worry

Question 23

Temporal stability of Eysenck’s PEN model

Answer 23

• Extraversion was stable within subjects over time periods ranging from 6 to 30 years, with a median correlation of .64 (ranges between .56 and .82)
• extraversion did not show substantial cross-sectional age differences
• Neuroticism was also stable over time periods ranging from 6 to 30 years, with a similar median correlation of .64 (ranges between .46 and .83)
• neuroticism did show substantial cross-sectional age differences in women but not in men (i.e., Srivastava et al., 2003)
• Costa and McCrae (1994) did not examine Psychoticism, but less stability is generally reported for this trait

Question 24

Temporal stability of Gray’s RST model

Answer 24

RST: Carver and White (1994) found that the test-retest reliability of the BAS-BIS questionnaires after eight weeks ranged between .59 and .69, which is “acceptable” (but not “good”)

Question 25

similarity across species in Eysneck’s PEN theory, Gosling and John (1999)

Answer 25

• Gosling and John (1999) reviewed 19 studies that had examined the presence of Extraversion and Neuroticism (and other domains) in 12 animal species
• Many but not all species displayed extravert and neurotic behaviour

Question 26

Similarity of species of Gray’s RST, Gray (1970)

Answer 26

• Gray conducted much research with animals, using lesions and psychopharmacology to study their behaviour
• In his work, Gray (1970) showed that rats have separate systems controlling their behaviour in reaction to the presence of rewarding and punishing stimuli

Question 27

what are some challenges faced when observing similarities across species?

Answer 27

• To improve the quality of research into personality traits among non-human animals, one can examine:
• Inter-rater reliability: Does Rater A agree with Rater B that Animal A is an extravert and Animal B is an introverted?
• Test-retest reliability: Does Animal A display extravert behaviour and does Animal B display introvert behaviour at Time 1 and Time 2?
• However, some concerns remain
  Are some personality traits easier to observe?
  Are some animal species easier to observe?

Question 28

cross-cultural evidence for Eysenck’s PEN theory, Caruso et al., (2001)

Answer 28

examined the internal consistency of the four domains from 69 datasets, which were taken from 44 studies that had used the EPQ in different countries
Whereas median internal consistency was “good” for Extraversion (α = .82) and Neuroticism (α = .83), “acceptable” for Lie (α = .78), but “questionable” for Psychoticism (α = .68)

Question 29

cross cultural evidence for Gray RST

Answer 29

Similar values of internal consistency have been found across different countries (1 = Carver & White, 1994; 2 = Heubeck et al., 1998; 3 = Gullo et al., 2011; 4 = Leone et al., 2001; 5 = Caci et al., 2007)

Question 30

Are there hereditary or genetic contributions to Eysencks’s PEN theory? Plomin et al (1994)

Answer 30

• Identify genetic influences by comparing traits in biologically and nonbiologically related family members
• Heritability accounts for 51% for Extraversion and 46% for Neuroticism, but Psychoticism was not measured

Question 31

Are there hereditary or gentic contributions for RST? Takashaki et al. (2007)

Answer 31

During childhood and adolescence, stable genetic influences on both BIS and BAS.

Question 32

candidate gene studies as an explanation for personality characteristics

Answer 32

• Associations between DNA blocks (called “SNPs”) in the D4 dopamine receptor (DRD4) gene and extraversion seeking (e.g., Benjamin et al. 1996; Ebstein 2006; Roussos et al. 2009).
• Variation in the serotonin transporter gene 5HTT (SERT or SLC6A4), which is responsible for re-uptake of 5-HT from synapses, was associated with neuroticism (Schinka et al. 2004; Sen et al. 2004) and with BIS scores (Whisman, Richardson and Smolen, 2011)
• Interactions between two gene loci that are related to the activity of the dopamine system were related to BAS scores (Reuter, Schmitz, Corr, & Hennig, 2006

Question 33

genome wide association studies explaining personality traits

Answer 33

• Interrogate hundreds of thousands to millions of SNPs across the entire genome
• Does not assume any prior knowledge about the underlying biology associated with the trait.
• Method entails MANY comparisons (across all DNA blocks), a correction to avoid type I error is applied (e.g., Bonferroni correction). This sets a very high threshold for significant results. Therefore, significant results can only be obtained in very large samples (N>5000) and often only across multiple cohorts (with Meta-analysis)
• Fast emerging research field: Neuroticism is currently the best-studied personality trait

Question 34

What type of brain structures can be linked to specific behaviours/traits?

Answer 34

• Cortical thickness: gray matter between the pial and white surface.
• Volume: also includes the surface area.
• Gyrification: the folding of the cortex.

Question 35

structural brain measures as an explanation for personality traits, Wright et al. (2006)

Answer 35

Wright et al. (2006) measured cortical thickness to look at the neuroanatomical correlates of extraversion and neuroticism.
- found that Extraversion was negatively correlated with cortical thickness in prefrontal regions, even after controlling for age and gender
- found that neuroticism was negatively correlated with cortical thickness in the orbitofrontal cortex (OFC), but this did not remain significant after controlling for gender

Question 36

Functional brain measures to explain personality traits, Barros-Loscertales et al (2001)

Answer 36

• Barrós-Loscertales et al. (2010) used fMRI to look at the association between BAS scores and brain activation.
• Letter discrimination task: is the letter a vowel?
  Letters are superimposed on a background image that is either neutral, appetitive (erotic), or aversive (murdered people, human threat, etc.)
• Sensitivity to Reward scale (SR): measures individual differences in attraction to positive stimuli
• Appetitive pictures would activate BAS-related regions, which would positively correlate with SR scores
• Aversive pictures would activate the BIS-FFFS structures, and these activations would correlate negatively with SR scores.