What were Galens + Hippocrates early ideas on how personality relates to the body ?
Thought there were 4 humors, each of which was responsible for a particular pattern of personality
Cloningers theory
Suggests that
a) dopamine promotes Novelty seeking
b) Serotonin inhibits Harm avoidance
c) Norepinephrine inhibits reward dependence
–> results of his studies have been mixed
What is Dopamine ?
What kind of personality dimension does its release elicit according to Cloninger ?
- A neurotransmitter that facilitates the transmission of signals of reward
- “Novelty seeking”, which is the tendency to seek pleasure + reward
What is Serotonin ?
What kind of personality dimension does its release elicit according to Cloninger ?
- A neurotransmitter that inhibits the transmission of signals of punishment
- An inactive serotonin system will elicit “Harm avoidance”, which is the tendency to avoid pain + anxiety
What is Norepinephrine ?
What kind of personality dimension does its release elicit according to Cloninger ?
- A neurotransmitter that inhibits the transmission of signals of conditioned reward
* stimuli that in past have been associated with reward - An inactive norepinephrine system will elicit “Reward dependence”, which is the tendency to develop strong sentimental attachments
Reinforcement sensitivity theory
(Gray)
Suggests that certain regions of the brain work together as systems that underlie personality
–> differences among people in the activity of these systems are the basis of important personality dimensions
Behavioral activation system/BAS (Gray)
Involves regions of the brain that indicate that rewards are being experienced
- “go” system, as it encourages the pursuit of rewards
- People differ in their tendency to be impulsive
- Similar to novelty seeking –> NAC
Behavioral inhibition system/BIS
(Gray)
Involves regions of the brain that indicate that punishments are being experienced
- “stop” system, as it encourages the avoidance of punishments
- People differ in their levels of anxiety
- Similar to harm avoidance –> amygdala
Fight-or-flight system/FFS (Gray)
Involves regions of the brain that motivate extreme reactions (fighting vs fleeing) in extremely threatening situations
- People differ in their tendency to show extreme reactions
- Similar to reward dependence
–> hypothalamus, amygdala
Psychobiological theory of personality
(Eysenck)
Similar to Grays theory, this one suggests that certain regions of the brain work together, where different “factors” underlie personality
–> forerunner of Grays theory
Extraversion factor
(Eysenck)
Differences stem from the strength of peoples reactions to stimulation of their senses
–> some prefer strong sensations (extroverts) , some less (introverts)
Which brain mechanism governs the individual differences in Extraversion ?
How does it achieve this ?
- Ascending reticular activating system (ARAS)
–> located in Brain stem
- Regulates the amount of stimulation that is admitted to the brain from NS
Neuroticism factor
(Eysenck)
Differences stem from the strength of peoples reactions to stressful stimuli
–> high vs low levels of anxiety
Which brain mechanisms govern the individual differences in Neuroticism ?
How do they achieve this ?
- Segments of the limbic system
- It regulates responses to stress
–> if LS tends to be overwhelmed by stressful stimuli = neurotic personality
Psychoticism factor (Eysenck)
Refers to a dimension that includes traits such as
a) aggressiveness
b) manipulation
c) tough-mindedness
Which brain mechanisms govern the individual differences in Psychotocism ?
Differing levels in testosterone + low levels of mono-amine oxidase
Testosterone
Is a hormone that is associated with disinhibited behavior
e.g.: higher levels tend to be correlated with aggression
Cortisol
Is a hormone that is triggered by physical or psychological stress
- serves as an indicator of an individuals overall emotional reactivity/ reactions to stress
e. g.: smaller levels indicate emotional insensitivity
–> related to FFS
Oxytocin
Is a hormone that plays a role in establishing attachments between persons/ emotional bonding
- produced in the hypothalamus + released by the pituitary gland
- interrelated with dopamine
e.g.: higher levels are associated with more trusting people
In which way does the o-RST differ from the r-RST ?
The original model mainly focused on motivational systems, e.g. BIS vs BAS which were poorly defined + understood
–> the revised model is more comprehensive, due to is better definitions of each proposed system, more biologically based
Personality neuroscience
The aim is to understand both the biological systems that are responsible for the states associated with traits + the parameters of those systems that cause them to function differently in different individuals
- Has focused primarily on traits which are relatively stable patterns of behavior, motivation, emotion + cognition
- Rests on the premise that the whole person can’t be understood without understanding the brain
–> EEF, fMRI
Lemon juice test
(Eysenck)
A researcher drops small amounts of lemon juice onto the tongues of participants, the measures the amounts of saliva that each participant produces in response
–> introverted participants would tend to produce the greatest amounts of saliva
Mono amine oxidase (MAO)
Is an enzyme that is involved in removing Dopamine, serotonin and norepinephrine
–> thus low levels will result in higher levels of those neurotransmitters and more positive feelings
Zuckermans criticism
The biological bases of personality are likely to be more complex than indicated by Eysenck, Clonginger and Gray
