Lecture 12&14-genetics and envt
Galen and Hippocrates believed in the 4 humours that were responsible for
- BLOOD: causes the sanguine or cheerful temperament
- BLACK BILE: causes the melancholic or depressed temperament
- YELLOW BILE: causes the choleric or angry temperament
- PHLEGM: causes the calm or phlegmatic temperament
- Biochemical substance that is involved in the communication among neurons
- One neuron transmits a message to another neuron. The electrical impulse travels
through the axon terminal and cause the neurotransmitter substance to be released
in the synapse. The neurotransmitters are absorbed by the dendrite of the other
- Electrical impulse travels along the axon towards the axon terminal.
- Depending on which neurotransmitter is involved, the molecules can either
encourage the neuron to send the electrical impulse to the next neuron or
discourage it from sending the message.
- Central nervous system is composed of the BRAIN and SPINAL CORD
- The three neurotransmitters active in this system are DOPAMINE, SEROTONIN
DOPAMINE & NOVELTY SEEKING:
- Facilitates the transmission of signals of reward.
- Helps neurons send messages in response to things that feel exciting or
- People with highly active dopamine system are excitement seeking, always
looking for adventure, impulsive, and are “Novelty Seeking”
- People whose dopamine system is inactive are not particularly motivated to find
fun and variety.
- Parkinson disease has inactive dopamine system
SEROTONIN & HARM AVOIDANCE:
- Serotonin inhibits the transmission of signals of punishment
- It prevents neurons from sending messages in response to things that feel harmful
- People who have a serotonin system that is INACTIVE will try to avoid pain and
anxiety; they are referred to as “harm avoidance”. Personality traits associated
with this are worry, pessimism, and shyness.
- PROZAC: activates the serotonin system. Taking this drug decreases negative
emotions such as depression
Lecture 12&14-genetics and envt
NOREPINEPHRINE AND REWARD DEPENDENCE:
- Aka noradrenalin
- Inhibits the transmission of signals of conditioned reward.
- Inactive system associated with sentimentality, warm communication and
- Active system associated with tendency not to develop sentimental attatchments
- “Reinforcement sensitivity theory” says that certain regions of the brain work
together as mechanisms or systems that underlie personality
- Activity of these systems influence personality dimensions
- Two systems are the behavioural activation system and behavioural inhibition
• Behavioural activation system:
- This is a part of the brain that receives signals from the nervous system that
indicate a reward is being experienced
- The nervous system sends signals to the activation system indicating a reward
- The activation system transmits these signals within the brain to communicate the
pleasurable nature of the rewards.
- May also be called the “go system”
- People differ in extent to which their go system is sensitive to reward stimuli
- The more sensitive it is the more people will seek pleasure and excitement.
Personality traits associated with a sensitive go system are impulsivity, etc. It is
comparable to the Novelty Seeking dimension
• Behavioural inhibition system:
- This part of the brain receives signals from the nervous system that indicate
punishment is being experienced
- Also called a “stop system” because it transmits signals throughout the brain to
communicate the painful nature of those rewards
- The more sensitive the stop system, the more a person will try to avoid pain and
- This is associated with the Harm Avoidance dimension
- Personality trait is anxious
• Fight or flight system:
- This region of the brain is responsible for motivating extreme reactions:
FIGHTING or FLIGTHING in threatening situations
- Fighting or fleeing are the two EXTREME reactions
- The more sensitive the system, the more likely one is to either fight or flee
- The system’s sensitivity does not influence what the individual will do (fight or
flight) but rather determine how likely they are to react in either extreme way.
- Associated with the Reward Dependence dimension
Lecture 12&14-genetics and envt
- Cloninger and Gray differ in the way that Cloninger puts a focus on the role of
neurotransmitters and Gray focuses on the brain structures.
- Worked on soldiers during WWII
- 3 major dimensions of personality
- Involves reaction to stimuli and arousability of the brain
- People are either sensitive to stimuli or less sensitive
- People who are less sensitive to stimuli prefer strong sensations and are attracted
to bright colours, loud noises, and meeting and interacting with people
- People who are sensitive to stimuli prefer less strong sensations and are
- Introverts avoid stimulation, prefer quieter environments and surroundings and
prefer to be alone
- Extraversion governed by brain mechanism: Ascending Reticular Activating
- ARAS is located in the brain stem where the spinal cord meets the brain
- The nervous system receives stimulation from the environment and sends signals
to the brain through the spinal cord.
- The ARAS works as a filter, admitting a certain amount of stimulation to the
- The extent to which ones ARAS admits little stimulation, the individual will seek
more stimulation – EXTROVERT
- The extent to which ones ARAS admits a great deal of stimulation, the individual
will avoid stimulation – INTROVERT.
- Some people are very sensitive to stressful stimuli: become anxious and fearful
- Some are less sensitive and do not become anxious.
- Neuroticism vs. Emotional stability
- Neurotic people will become quickly stressed when faced with a problem where
as emotionally stable people will stay calm and not be affected.
- The limbic system is associated with neuroticism because it regulates the response
- The extent to which the system can handle stress indicated whether the person has
a neurotic personality or stable personality
- Personality traits of this dimension include aggressiveness, manipulation,
- High levels of Psychoticism associated with criminal behaviour
- Associated with high levels of testosterone
- REVIEW EXPERIMENTS ON PAGE 103,104
Galen and hippocrates believed in the 4 humours that were responsible for particular personalities: Blood: causes the sanguine or cheerful temperament. Black bile: causes the melancholic or depressed temperament. Yellow bile: causes the choleric or angry temperament. Phlegm: causes the calm or phlegmatic temperament. Biochemical substance that is involved in the communication among neurons. One neuron transmits a message to another neuron. The electrical impulse travels through the axon terminal and cause the neurotransmitter substance to be released in the synapse. The neurotransmitters are absorbed by the dendrite of the other neuron. Electrical impulse travels along the axon towards the axon terminal. Depending on which neurotransmitter is involved, the molecules can either encourage the neuron to send the electrical impulse to the next neuron or discourage it from sending the message. Central nervous system is composed of the brain and spinal cord. The three neurotransmitters active in this system are dopamine, serotonin. Facilitates the transmission of signals of reward.