This is the Chapter 15 of the book The Individual (de Bruin, E., 1st Edition). Which is content for the exam of the Theory component of Module 4 (The Individual) of the University of Twente, in the Netherlands

Physiological Approaches to Personality

“the organization [of personality] entails the operation of both body and mind, inextricably fused into a personal unity” Gordon Allport

• Galen: idea that elements of personality are products of biological processes
  • Four fluids present in the body -->  determine personality
    • Phlegmatic: abundance of phlegm --> passive, calm, thoughtful
    • Sanguine: abundance of blood --> happy, outgoing, lively
    • Choleric: too much yellow bile --> unstable, aggressive and excitable
    • Melancholic: abundance of black bile --> unhappy, pessimistic
• Physiologically-oriented approaches: observe behavioural differences and try to explain these by studying underlying biological structures
  
  • Physiological characteristics: functioning of organ systems within the body
    
    • Physiological systems:
      
      • Nervous system (including brain and nerves)
      • Cardiac system (including heart, arteries and veins)
      • Musculoskeletal system (including muscles and bones, which make all movements and behaviours possible)
    • Differences in physiological characteristics --> related to differences in important personality characteristics and behaviour patterns

A Physiological Approach to Personality

• Theoretical bridge between personality dimension of interest and physiological variables in order to use physiological concepts to help explain personality
• Subject reactivity: each person reacts somewhat differently to the same phenomenon, which makes it difficult to truly understand a certain phenomenon
  
  • To circumvent the problem of subjective reactivity, we can tap directly inside the body to objectively measure what’s going on --> tie emotional processing to physiological system without having to ask the individual how they feel

Physiological Measures Used in Personality Research

• Electrodes: sensors, placed on the surface of a participant’s skin
  • Non-invasive, causes no discomfort
  • Movement is constrained
    
    • New generation of electrodes to overcome this limitation
      
      • Telemetry: process by which electrical signals are sent form the participants to the recording divide, though radio waves instead of by wires

Electrodermal Activity (Skin conductance)

• Sweat glands are directly influenced by the sympathetic nervous system (branch of the Autonomic Nervous System)
  • The more water in the skin, the more easily the skin carries/conducts electricity --> directly measure sympathetic nervous system activity
    • High in anxiety and neuroticism appear to have sympathetic nervous system that are in a state of chronic activation

Cardiovascular Activity

“Person’s cardiovascular system when they are challenged by having to perform a stressful task, the blood pressure and heart rate go up during a stressful task”

• Cardiovascular System: involves the heart and associated blood vessels
  • Blood pressure: pressure exerted by the blood on the inside of the artery walls, typically expressed with two numbers:
    • Diastolic pressure: refers to the resting pressure inside the system between heart contradictions
    • Systolic pressure: maximum pressure within the cardiovascular system produced when the heart muscle contracts
  • Heart rate: cardiovascular measure --> as it increases, it indicates that the person’s body is preparing for action, it also increases with cognitive action
  • Cardiac reactivity: associated with Type A Personality --> characterized by impatience, competitiveness and hostility

Brain Activity

“Personality is associated with brain reactivity to emotional stimuli”

• Electroencephalography (EEG): small amounts of electricity measured by electrodes placed on the scalp
  • Evoked potential technique: brain EEG is measured when the participant is given a stimulus --> assesses brain’s responsiveness to the stimulus
• Functional Magnetic Resonance Imaging (fMRI): allows to look inside the working brains of the patients --> shows which portions of the brain are active while the person is performing a particular task
• Canli et al. (2001): personality correlated with the degree of brain activation in response to the positive and negative images
  
  • E.g. Neuroticism correlate with increase frontal brain activation to negative images

Other Measures:

• Saliva samples: biochemists can extract indicators of how competently a person’s immune system is functioning
  • Quality of immune system may go up and down with stress or emotions and thereby may relate to personality
• Cortisol: by-product of the hormone noradrenaline, assessed from saliva samples
  
  • “Cortisol levels after awakening are positively associated with extraversion”
• Monoamine oxidase (MAO): enzyme found in blood, is known to regulate neurotransmitters (the chemicals that carry messages between nerves cells)
  
  • “MAO may be a causal factor in the personality trait of sensation seeking”

Physiologically based Theories of Personalities

• Gnome: the whole of our genetic makeup, codes for and largely determines the development of our organs and physiological systems (cardiovascular system/communication systems; neurotransmitters/endocrine system; hormones)
  • Physiological systems largely determined by their anatomy, which remains stable over time --> leads to consistency/stability in reactions/behavioural patterns due to the influence of these systems on that behaviour

Extraversion-Introversion

• Eysenck’s theory: introverts are characterised by higher levels of activity in the brain’s ascending reticular activating system (ARAS): controls overall cortex --> if the gate is somewhat closed, then the resistance arousal level of the cortex is lower
• Hebb’s (1955) ‘optimal level of arousal’: level that is just right for any given task
  
  • “There is an optimal level of arousal for taking an exam, one in which you are focused, alert, attentive, but not aroused to the point of anxiety”
• For introverts, ARAS lets too much stimulation
  
  • Qualities that typically characterize introverts --> understood to be attempts to regulate arousal downwards
• Arousability: “Evidence now suggests that the real difference between introverts and extroverts lies in their arousal response, not in their baseline arousal level”
  
  • E.g. Imagine an emergency at the nuclear power plant, with sirens blasting, lights flashing --> an extrovert would perform better, due to the introvert’s tendency towards over-arousal in response to stimulation

Sensitivity to Rewards and Punishment

• Reinforcement sensitivity theory: model of human personality based on two hypothesized biological systems in the brain
  • Behavioural activation system (BAS): responsive to incentives, and regulates approach behaviour --> when BAS recognizes a stimulus as potentially rewarding, it triggers approach behaviour
    • Responsible for the personality dimension of impulsivity
    • Impulsive person is deficient in learning through punishment
  • Behavioural inhibition system (BIS): responsive to cues for punishment, frustration and uncertainty. The effects of BIS activation is to cease/inhibit behaviour or to bring about avoidance behaviour
    
    • Responsible for the personality dimension of anxiety

Sensation Seeking:

• Sensation Seeking: marked physiological basis --> tendency to seek our thrilling and exciting activities, to take risks and to avoid boredom --> studies on sensory deprivation

Hebb’s Theory of Optimal Level of Arousal

• People are motivated to reach an optimal level of arousal
  • If under-aroused --> an increase in arousal is rewarding
  • If over-aroused --> a decrease in arousal is rewarding
• The nervous system appears to need at least some sensory input

Zuckerman’s Research:

• Sensation-Seeking Scale: designed to measure the extent to which a person needs novel or exciting experiences and enjoys the thrills and excitement associated with them --> Eysenck extraversion: positive correlation between extraversion and sensation seeking
  • Thrill and adventure seeking: items that ask about desire for activities involving elements of risk
  • Experience seeking: Reflected in items that refer to the seeking of new sensory or mental experiences through unconventional or non-conforming lifestyle choices
  • Disinhibition: Reflected in items indicating a preference for getting ‘out of control’
  • Boredom susceptibility: Reflected in items that refer to a dislike for repetition, routine work, monotony, predicable and dull people, and a restlessness
• Zuckerman: physiologival basis for sensation-seeking behaviour --> role played by neurotransmitters in bringing about differences in sesnsation seeking
  
  • Neurotransmitters: chemicals in the nerve cells responsible for the transmission of a nerve impulse from one cell to another
  • Synapse: nerve cells are separated from one another by slight gap --> nerve impulse must jump across the gap to continue towards its destination --> neurotransmitter allow nerve impulses to jump across the synapse
  • Monoamine Oxidase (MAO): enzymes responsible for maintaining the proper levels of neurotransmitters, by breaking them down after it has allowed a nerve impulse pass
  • High sensation seekers: low levels of MAO in their bloodstream
    
    • Sensation seeking is caused by or is maintained by having high levels of neurotransmitters in the nervous system.
    • MAO acts by inhibiting neurotransmission: low MAO levels --> less inhibition in their nervous system and therefore less control over behaviour

Neurotransmitters and Personality:

Dopamine:

• Associated with pleasure
• Cocaine mimics dopamine in nervous system
• Amphetamine: diminish a person’s natural levels of dopamine leading to unpleasant feelings after the drug leaves the nervous system
• “The short-term, dopamine-driven feedback loops that we have created are destroying how society work’. Indeed, social media leverage the same neural circuitry used by slot machines in the casino and cocaine and amphetamine”

Serotonin:

• Role in regulating impulsive aggression --> it inhibits aggressive social reactions
  • Explains why we tend to react more aggressively when we are on a diet or have not eten yet
• Drugs such as Prozac, Seroxat and Zoloft block the reuptake of serotonin, leaving it in the synapse longer, leading depressed person to feel less depressed
  
  • In animal studies: low serotonin is associated with irritable behaviour

Norepinephrine (or noradrenaline):

• Involved in activating the sympathetic nervous system for fight-flight
• Cloninger’s tridimensional personality model: three personality traits are tied to levels of the three neurotransmitters
  
  • Novelty seeking: based on low levels of dopamine --> low levels of dopamine create a drive state to obtain substances or experiences that increase dopamine
  • Harm avoidance: abnormalities in serotonin metabolism: very low ;levels of serotonin --> risk of severe depression
    
    • Selective serotonin uptake inhibitors: may increase anxiety initially, but then lead to decreased vulnerability to over-reacting to stress, probably by down-regulating sensitivity to serotonin when it is released in response to stress (serotonin is increased in states of acute stress)
  • Reward dependence: low levels of norepinephrine --> people high on this trait are persistent; they continue to act in ways that produce reward

Genes influence personality:

• Type 4 dopamine receptor gene (DRD4): associated with heightened levels of novelty seeking
  • Imply that many genes will be involved in the creation of any single personality trait --> multiple genes that interact in complex ways to influence neurotransmitter system (personality)
• Cloninger’s theory: help explain various types of addiction
  
  • Some alcoholics began drinking due to high novelty seeking
  • Other alcoholics began drinking because they are high in harm avoidance

Morningness-Eveningness:

• Morningness-Eveningness: differences between morning and evening types of person --> appear to be due to differences in underlying biological rhythms.
  • Circadian rhythms: fluctuate around an approximate 24- to 25-hour cycle --> the light-dark cycle
    • Shorter biological rhythms tend to be morning persons
    • Longer biological rhythms tend to be evening persons
• Free running: environment where there are no times cues to influence your behaviour or biology
  
  • Circadian rhythms in temporal-isolation studies have been found to be as short as 16 hours in one person and as long as 50 hours in another person

Brain asymmetry and affective style

• Left and right sides of the brain are specialized, with asymmetry in the control of various psychological functions
• Alpha wave: amount of alpha wave present in a given time period is an inverse indicator of brain activity during that time period. Alpha wave is given off when a person is calm, relaxed and is feeling a bit sleepy and not attentive to the environment
  
  • Left hemisphere is relatively more active when experiencing pleasant emotions
• Standard anxiety-producing procedure: infants left alone, whereupon a stranger entered the room --> some infants become distressed but some do not
  
  • Individuals differences in frontal brain asymmetry exhibit enough stability and consistency to be considered indicative of an underlying biological disposition or trait
    
    • Right-side-dominant participants reporting more distress in response to the unpleasant films --> persons with a left- or right-sided pattern require less of the affective stimulus to evoke the corresponding emotion
    • Dispositionally positive person: showed greater relative left frontal EEG asymmetry at baseline, in the absence of emotional stimulation
• Dalai Lama describing mindfulness meditation:
  
  • “Non-sectarian technique involving a state of alertness in which the mind does not get caught up in thoughts or sensations, but lets them come and go, much like watching a river flow by … these methods are not just useful, but inexpensive. You don’t need a drug an injection. You don’t have to become a Buddhist, or adopt any particular religion. Everybody has the potential to lead a peaceful, meaningful life”
  • Practicing such mindfulness can bring about changes in biology