Biological Aspects of Personality

1. Biological Aspects of Personality Theories of Personality Prepared by: Jim Messina, Ph.D.

2. Key Biological Theorists • Charles Darwin • Ivan Pavlov • Hans Eysenck 1916-1997 • Francis Galton

3. Evolutionary Personality Theory • Application of Darwin’s Theory of Evolution • Function of a survival characteristic evolves over time • Belief that many of individual characteristics are “in our bones” in our genes

4. Natural Selection • Process by which certain adaptive characteristics emerge over generations

5. Examples of Genetic Personality Types • Angelman Syndrome – chromosome 15 • Friendly • Oral driven • Downs Syndrome - chromosome 21 • Friendly – easy to get along with • Caring, Loving • Approval seeking

6. Study of Temperaments-Based on Work of Pavlov • Temperament: stable individual differences in emotional reactivity which remain stable as children mature • Different nervous system responses to unpleasant stimuli

7. 4 Basic Aspects of Temperament • Social-Introversion-Extroversion- seek or avoid being with/in front people • Emotionality-fearful, angry, mood swings vs relaxed, calm, placid, stable • Activity-vigorous, always in motion vs passive, lethargic • Impulsive-aggressive-bully vs peace maker, plans vs quick changes, cold vs conscientious & friendly

8. Introversion vs Extroversion • Hans Eysenck – ties this to central nervous system – Biologically based personality theory • Extroverts – Low level of Brain arousal and seek stimulation • Introverts – High level of Brain arousal shy away from over-stimulation

10. Nervous System Arousal • Stable people-well-modulated nervous systems • Neurotic people-very reactive nervous systems • Tests: EEG, Electrodermal measure (lie detector)

11. Sensation Seeking • Seek new challenge or new high • Seek highly stimulating activities • Attracted to unknown • Low level of natural (internal biological) activation –seek arousal from environment • Left and right side of Brain

12. The Brain • Brain reaches its maximum number of synaptic connections and its greatest metabolic activity around age 3 or 4

16. Brain Hemispheric Hypothesis • Left side of Brain-Role in Positive Emotions-Creative side of Brain • Right side of Brain-Role in Negative Emotions-Methodological, systematic side of Brain • Try out this test to get the impact of right and left hemisphere operations

19. Top view of Brain • genu of the corpus collosum • head of caudate nucleus • putamen • globus pallidus • thalamus • tail of caudate nucleus • splenium of corpus callosum • amygdala • substantia nigra

20. PET Scan of Brain of Adult with ADHD

21. PET Scans • Demonstrates metabolism of glucose in brain under arousal • Brain on left is normal adult brain under arousal • Brain on right is Brain of Adult with ADHD – • frontal lobe of brain most involved in adults with ADHD

24. Messages from Brain Travel by Nervous System • The Central Nervous System is the Communications Highway of the body • Brings help to the body based on the messages it screens from the environment

28. Neurons where the messages are delivered! • Bio-chemical electrical impulses create a cascade of effects based on the message sent to various organ receptors of the body

32. Neurotransmitters Impacted Too! • Not only are there physiological changes but there is altering of neurotransmitters based on messages from brain • Absence or overabundance can create whole new set of consequences

33. Neurotransmitters • Brain = Billions of Brain Cells-Neurons • Neurons transmit information – electrical conduction within nerve cells & between nerve cells • Message once carried through body cell (Axon) crosses space –Synapse to receiving cell

34. Neurotransmitters • Tip of Axon-tiny sacs contain neurotransmitter chemicals which are automatically released by sending nerve cell • Neurotransmitter chemicals excite receiving cell causing cell to fire to send message through its own body-Axon to next receiving cell • Once message received neurotransmitter is deactivated and taken up from synapse and stored in sacs so as not to cause repeated firing of the receiving cell

42. Types of Neurotransmitters • Dopamine-dopaminergic system • Norepinephrine-noradrenergic system • Serotonin-serotonergic system • Control senses, thinking, perception, mood, attention, and behavior • Unfortunately at this time we can not measure amount for baseline therapeutic levels

43. Hans Eysenck- • 3 Type Theory –Biological Determinism-Heredity in Everything • E – Extraversion – linked to ascending reticular activating system (ARAS)-reticular formation of Brain Stem • N – Neuroticism – linked to limbic system-brains emotional center regulates sex, fear & aggression • P – Psychoticism – linked to endocrine gland-especially which controls sex drive

44. Eysenck’s Types • E-extraversion – introversion • Neuroticism-stability • Psychoticism-superego functioning • People show degrees of all 3 types • Encouraged Twin studies especially of identical twins who were adopted separately

45. Sir Francis Galton • Supposition that Upper Class Englishmen were a superior population • Began the study of adoptive twins • Began the “eugenics” movement • Encouraged eminent families to have lots of children to improve the human blood lines

46. Eugenics • Good Birth or Good Genes is the cause of peoples’ high intelligence and stable emotional well-being • Recommend forced sterilization of the poor

47. Kin Selection • Nieces and nephews of people with certain traits thought to be genetic based- homosexuality, schizophrenia, bipolar disorder – genetic tendency toward these conditions survives since nephews and nieces share some genetic makeup with uncle or aunt who has these traits.

48. Mediated effects of Biology • Disease-Parkinson’s, ear, heart, lung, systemic, surgery • Poisoning-mercury, lead, manganese • Brain disease-Alzheimer’s, strokes, epilepsy, tumors • Illegal drugs, LSD, cocaine, crack

49. Somatotypology-W.H.Sheldon, 1942 • Three Body Types have influence on personality: • Mesomorphs-muscular, large boned, athletic • Ectomorphs- slender, bookworm • Endomorphs- overweight, roly-poly, good natured

50. Survival of the Fittest • Darwin’s concept that the fittest survive over time • Misused to mean: weak creatures should not survive • Pseudoscientific justification for the oppression of minorities