Personality & Biology: Theories

Question 1

The two most influential biologically based theories of personality are both founded from the classical temperaments. Name these 2 theories and what is the main difference between the two?

Answer 1

Eysenck’s arousal theory of extraversion
- pitted at the neuroanotomical level
Greys reinforcement sensitivity theory
- pitted more at the neurotransmitter level

Question 2

What were Eysenck’s influences behind his arousal theory of extraversion?

Answer 2

• Pavlov
• Ascending Reticular Activating System (ARAS - Moruzzi & Magoun, 1949
• Eysenck’s theory of N & P

Question 3

What were Grey’s influences behind his reinforcement sensitivity theory!

Answer 3

• Pavlov
• BIS & BAS

Question 4

According to the classical temperaments, a combination of Extraversion & neuroticism would indicate?

Answer 4

Question 5

According to the classical temperaments, a combination of Extraversion & emotional stability would indicate?

Answer 5

Sanguine

Question 6

According to the classical temperaments, a combination of Introversion & neuroticism would indicate?

Answer 6

Melancholic

Question 7

According to the classical temperaments, a combination of emotionally stable & introversion would indicate?

Answer 7

Phlegmatic

Question 8

Pavlov’s work on canine temperament showed….?

Answer 8

If a neutral stimulus is regularly paired with an unconditioned stimulus, it acquires the capacity to elicit the salivary response, even when it is subsequently presented without the unconditioned stimulus.

Question 9

In regards to Pavlov’s work on the strength of the conditioned reflex, what was strength thought to index?

Answer 9

The working capacity of the cortical cells

Question 10

The Law of Strength (Pavlov) means?

Answer 10

That the strength of the conditioned response is directly proportional to the intensity of the conditioned stimulus.

Question 11

Transmarginal Inhibition (Pavlov) is?

Answer 11

The law of strength is self-limiting. Ultra strong stimulus produce a reduction in response magnitude.

Question 12

What did Pavlov relate the onset of transmarginal inhibition to?

Answer 12

The classical temperaments.

Question 13

Pavlov found melancholic dogs showed what in terms of the onset of transmarginal inhibition?

Answer 13

Melancholic dogs showed early onset of transmarginal inhibition. Believed to have a weak nervous system (I.e. highly reactive cortical cells that risked becoming functionally exhausted at lower stimulus intensities.

Question 14

Pavlov found sanguine dogs showed what in terms of the onset of transmarginal inhibition?

Answer 14

Sanguine dogs showed a delayed onset of transmarginal inhibition. Believed to posses a strong nervous system (I.e low reactive cortical cells that required far greater stimulus intensity before being at risk of functional exhaustion.

Question 15

Pavlov accounted the excitatory conditioned responses and transmarginal inhibition processes as being operated entirely by the cerebral cortex. How did Moruzzi & Magoun’s findings influence Eysenck’s arousal theory of extraversion?

Answer 15

Moruzzi & Magoun’s experiments on anaesthetised cats provided the discovery of the subcortical structure - the reticular activating system. This finding is what underpins Eysenck’s arousal theory.

Question 16

Moruzzi &Magoun attached 2 different types of electrodes to the anaesthetised cat. Explain?

Answer 16

The first type of electrodes were non invasive, attached to the surface of the cats scalp so as to record electrical activity of the cortex.

The second type were surgically implanted into the cats brain stem reticular system. These were stimulating electrodes, used to deliver electrical stimulation.

Question 17

Prior to delivering any stimulation to the brain stem reticular system, the electrodes Moruzzi and Magoun attached to the anaesthetised cats scalp showed?

Answer 17

Recording showed slow Delta waves, the kind of waves you get from cats and humans when sleeping.

Question 18

What did Moruzzi & Magoun discover when the started stimulation of the brain stem reticular system?

Answer 18

Suddenly the cortical activity changed form Delta waves to fast frequency Beta waves. The kind that are recorded when cats/humans are alert, attentive, or actively engaged in problem solving. Not the kind you would expect to find in an anaesthetised cat.

Question 19

In terms of the ascending reticular activating system, the classical ascending afferent pathway is?

Answer 19

Neural messages are sent via the specific thalamic nuclei to the relevant projection regions in the cortex (very specific pathway)

Question 20

In terms of the ascending reticular activating system, the classical ascending collateral pathway is?

Answer 20

A pathway that sends collaterals to the ascending reticular activating system, which when activated relays a flood of nonspecific excitation to the cortex.

Question 21

How is the ascending reticular activating system linked to Pavlov’s proposed transmarginal inhibition?

Answer 21

There are well documented pathways from the cortex that travel down to the brain stem reticular system. These pathways are primarily inhibitory in nature. Thus the cortex can inhibit the level of stimulation from the ascending reticular activating system by descending pathways, preventing over responsiveness of the brain.

Question 22

In 1967, Eysenck linked extraversion differences to differences in sensitivity of the ascending reticular activating system. What did Eysenck say?

Answer 22

“Neural pathways going along the classical ascending afferent pathways relay to the particular projection areas involved in the cortex; they also send collaterals into the reticular formation, which in turn sends arousal messages to the cortex to keep it in a state of functional tonus. Depending on the nature of the information transmitted, the cortex in turn instructs the reticular formation to continue sending arousal messages or else switch to inhibition. This loop then is concerned with information processing, with cortical arousal and inhibition, and it’s application to personally differences with introversion and extraversion.”

Question 23

Using Freudian language, explain the cost of the activation and inhibition processes of the ARAS working together to regulate activity .

Answer 23

The flood of activity to the cortex & the prefrontal cortex trying to inhibit activity as Freud would argue - there is only so much energy in the system and the brain simply cannot sustain that level of activity for long. If these processes continue for an extended period time, then too much energy taken up in catharsis and anti catharsis processes.

Question 24

According to Eysenck’s arousal theory of extraversion, the same incoming stimulus will have what 2 different affects for an extrovert as opposed to an introvert ?

Answer 24

Extroverts - the same incoming stimulus will create only a trickle of activity due to a low reactive ascending reticular activating system, leading to lower cortical arousal.
Introvert- the same incoming stimulus will create a flood of activity due to a highly reactive ascending reticular activating system, amplifying the value of incoming stimuli, leading to higher cortical arousal.

Question 25

Drawing from Hebb’s work, Eysenck argued?

Answer 25

That cortical arousal difference between introverts and extroverts have far reaching implications in terms of both performance and motivation.

Question 26

How did Hebb characterise the relationship between the ascending reticular activating system induced nonspecific cortical arousal & performance?

Answer 26

In terms of an inverted U function. I.E there exists an optimal level of cortical arousal

Question 27

Taking Hebb’s idea of optimal arousal level, Eysenck argues what in terms of introvert/extrovert differences and performance?

Answer 27

If extroverts have a less reactive ARAS which dampens the value of stimuli, extroverts will reach the optimal level of cortical arousal for performance at higher levels of stimulation.

Question 28

What were the results of Eysenck’s assessment of extraverts / introverts and their performance in a boring math task that involved continuous tapping of a metal board with a metal stylus for an extended amount of time?

Answer 28

Extraverts were more prone to many more involuntary rest pauses than introverts. An involuntary test pause is where the participants involuntarily losses concentration for a moment.
- Eysenck argued that under monotonous conditions, extraverts are prone to involuntary rest pauses because their cortex is aroused at a suboptimal level.

Question 29

Hebb (1955) also linked nonspecific cortical arousal levels to affect and mood. Explain further.

Answer 29

Low and high levels of cortical arousal produce negative affect. We are motivated to find some intermediate level of arousal that is not only optimal for performance but also pleasant.

Question 30

Hebb conducted a series of studies that utilised sensory deprivation conditions; no light, no sound, minimal tactile stimulation. The only thing of interest was a tape deck that contained a lecture intended to convince 6 yr olds of the dangers of alcohol consumption. What were Hebb’s findings?

Answer 30

Hebb found that participants would chose to listen to the same taped message over and over again. Hebb concluded that the boring tape allowed the uni students to escape the consequences of sensory deprivation.
- According to Hebb, when the level of stimulation gets too low, we are have a drive to seek out stimulation. Yet, when stimulation reaches unpleasant levels, we are motivated to reduce the level of stimulation that the brain is receiving.

Question 31

Eysenck took Hebb’s ideas around mood and motivation and applied them how to introverts?

Answer 31

If introverts have a highly sensitive ascending reticular activating system which amplifies the value of incoming stimuli, they regularly risk unpleasantly high levels of cortical arousal. Introverts will have a drive to lower the levels of stimulation in their lives in order to reach a pleasant level of arousal.
- Stimulus aversion: introverts are motivated to seek out low arousing situations and avoid active social interactions which may easily cause them to become over-stimulated.

Question 32

Eysenck took Hebb’s ideas around mood and motivation and applied them how to extraverts?

Answer 32

If extraverts have a low reactive ascending reticular activating system which dampens the value of incoming stimuli they regularly risk unpleasantly low levels of cortical arousal - extraverts will have a drive to seek out higher levels of stimulation in their lives in order to reach a pleasant level of arousal.
- stimulus hunger: extraverts are motivated to seek out stimulating activities and engage in more unrestrained behaviours.

Question 33

How does Eysenck link his own theory of Neuroticism to his arousal theory of extraversion?

Answer 33

Neurotics have a more reactive limbic system than stable individuals. This greater sensitivity makes neurotic individuals more susceptible to mood fluctuations, fear and anxiety.
- are thought to find situations involving high ego threat more anxiety-provoking (competitive, complex, and evaluative situations )

Question 34

How does Eysenck link his own theory of Psychoticism to his arousal theory of extraversion?

Answer 34

Eysenck has little to say about the biological basis of Psychoticism.
- he only offers that testosterone levels might be implicated. Based on the notion that males tend to score higher on the Psychoticism scale than females.

Question 35

While Eysenck cast his personality theory in terms of differences in arousal, Gray focused on what differences?

Answer 35

Differences in the sensitivity to reward and punishment.

Question 36

Pavlov ‘s early work focused on the speed of conditionability (the number of trials required to establish a conditioned response). He used both food powder and acid (unconditioned stimulus - remember the bell tone is the neutral stimulus) but he made no distinction between the two, opting to use food powder more. How many presentations of the UCS did it take to form a CR+

Answer 36

Sanguine dog = 27 presentations
Melancholic dog = 147 presentations

Question 37

Gray argued had Eysenck used acid as the UCS then what?

Answer 37

It would have been the Melancholic dogs who learned the conditioned response quicker.

Question 38

Although Pavlov made no distinction between appetitive conditioning (reward) and aversive conditioning (punishment), Gray did, arguing what?

Answer 38

Gray argued that the speed of conditionability will depend on whether the UCS is a reward (eg food powder) or a punishment (eg acid).

Question 39

Gray has constructed a model of personality based on 2 hypothetical biological systems that respond to different subclasses of reinforcing events; the BAS & the BIS. What is the BAS?

Answer 39

The Behavioural Activation System is activated by conditioned stimulus associated with reward (I. E signals of reward).
CS+ (tone) signals reward (food) ~BAS ~ Approach behaviour

Question 40

Gray has constructed a model of personality based on 2 hypothetical biological systems that respond to different subclasses of reinforcing events; the BAS & the BIS. What is the BIS?

Answer 40

Behavioural Inhibition System is activated by conditioned aversive stimuli (I.e signals of punishment, frustrative non reward, novelty.
CS+ (tone) signals punishment (acid) ~ BIS ~ avoidance behaviour

Question 41

In reference to Gray’s reinforcement sensitivity theory, differences in the sensitivity of the BAS are thought to underline differences in what? Explain.

Answer 41

Impulsivity
Individuals with a very active BAS - who are sensitive to signals of reward - will be less able to inhibit approach behaviour, especially in the presence of desirable goals or rewards.

Question 42

In reference to Gray’s reinforcement sensitivity theory, differences in the sensitivity of the BIS are thought to underline differences in what? Explain.

Answer 42

Anxiety
People with a very active behavioural inhibition system - who are more sensitive to signals of punishment and frustration - will tend to be inhibited and anxious. Moreover, they will find uncertainty and novelty more distressing.

Question 43

Gray locates his dimensions of impulsivity and anxiety within the 2 dimensional space defined by Eysenck’s E & N. Explain the dimension of impulsivity further.

Answer 43

Gray argues the impulsivity continuum sits at about a 10 degree rotation of Eysenck’s Extraversion.
Thus, impulsive individuals lean towards the choleric.

Question 44

Gray locates his dimensions of impulsivity and anxiety within the 2 dimensional space defined by Eysenck’s E & N. Explain the dimension of anxiety further.

Answer 44

Gray argued the anxiety continuum sits at about a 10 degree rotation of Eysenck’s Neuroticism. Anxious individuals are essentially neurotic individuals who are also a little bit introverted.
Thus, neurotic individuals who lean towards the melancholic.

Question 45

Gray links the Behavioural Activation System with which biological substrate pathways?

Answer 45

The dopaminergic pathways .

Question 46

Dopamine appears to function like a reward system and has been called the feeling good chemical. Give an example.

Answer 46

Animals will work to obtain doses of dopamine, much as they would work to obtain food.
Drugs like cocaine mimic the dopamine nervous system which accounts for the pleasure associated with taking it, yet cocaine depletes a person’s natural levels of dopamine

Question 47

Gray primarily associates the Behavioural Inhibition System with what biological substrate pathways?

Answer 47

Noradrenergic pathways.

Question 48

The link between the Behavioural Inhibition System and the noradrenergic system is based primarily on what neuropsychological evidence?

Answer 48

Destruction of the ascending noradrenergic system impairs passive-avoidance learning in rats.