1. Psychology 3051 Psychology 305B: Theories of Personality Lecture 6

2. Psychology 3052 Scoring Your Questionnaire 1.Reverse score items 6, 18, and 19. 2. Sum the following items: 2, 7, 10, 17 1, 6, 15, 20 5, 8, 13, 18 4, 9, 11, 16 3, 12, 14, 19 3. Divide each sum by 4.

3. Psychology 3053 Lecture 6 Questions That Will be Answered in Today’s Lecture Biological Perspective on Personality: Behavioural Genetics Approach 1. What are the goals of behavioural genetics? 2. What are heritability and environmentality and how are they assessed? 3. What personality characteristics are heritable?

4. Psychology 3054 Physiological Approach 1.Case example: Who was Phineas Gage? 2.What physiological theories of personality were proposed by early scientists?

5. Psychology 3055 What are the goals of behavioural genetics? Goal 1: To determine the degree to which individual differences in personality characteristics are caused by genetic factors as opposed to environmental factors: V P = V G + V E V P = Variation in an observable personality characteristic within a population. V G = Variation in the genetic factors that contribute to that characteristic. V E = Variation in the environmental factors that contribute to that characteristic. Behavioural Genetics Approach

6. Psychology 3056 Goal 2: To identify the genetic factors that contribute to individual differences in specific personality characteristics. E.g., the gene D4DR on chromosome 11 contributes to individual differences in “sensation seeking.” Goal 3: To identify the environmental factors that contribute to individual differences in specific personality characteristics.

7. Psychology 3057 Heritability: The proportion of phenotypic variance that is attributable to genotypic variance. What are heritability and environmentality and how are they assessed? Phenotypic variance: Individual differences in an observable characteristic (e.g., height, weight, aggression, ambition, extraversion). Genotypic variance: Individual differences in genetic makeup.

8. Psychology 3058 E.g., Heritability of aggression =.67. Indicates that 67% of the observed variance in aggression within a population is due to individual differences in genetic makeup.

9. Psychology 3059 Environmentality: The proportion of phenotypic variance that is attributable to variance in environmental factors. E.g., Environmentality of ambition =.62. Indicates that 62% of the observed variance in ambition within a population is due to individual differences in environmental factors.

10. Psychology 30510 Heritability and environmentality are assessed using 3 methods: 1. Family Studies  Examine whether or not participants are more similar to immediate family members than distant family members with respect to a given personality characteristic.

11. Psychology 30511 Proportion of genes shared Parents and children Non-twin siblings Grandparents and grandchildren Aunts/uncles and nieces/nephews First cousins 50% 25% 12.5%

12. Psychology 30512  For a given personality characteristic, two correlations are calculated: r 2 : The correlation between participants’ scores and the scores of their distant family members on the characteristic (reflects a relatively small degree of genetic overlap). r 1 : The correlation between participants’ scores and the scores of their immediate family members on the characteristic (reflects a relatively large degree of genetic overlap).  r 1 > r 2 indicates that the personality characteristic is heritable.

13. Psychology 30513 2. Adoption Studies  Examine whether or not adopted children are more similar to their biological parents than their adoptive parents with respect to a given personality characteristic.  A more powerful means by which to assess heritability and environmentality.

14. Psychology 30514  For a given personality characteristic, two correlations are calculated: r 2 : The correlation between participants’ scores and the scores of their adoptive parents on the characteristic (reflects the influence of shared environment).  r 1 > r 2 indicates that the personality characteristic is heritable. r 1 : The correlation between participants’ scores and the scores of their biological parents on the characteristic (reflects the influence of shared genes).

15. Psychology 30515 3. Twin Studies  Examine whether or not monozygotic (MZ) twins are more similar than dizygotic (DZ) twins with respect to a given personality characteristic.  The most powerful means by which to assess heritability and environmentality.  MZ twins share 100% of the same genes; DZ twins share 50% of the same genes.

16. Psychology 30516  For a given personality characteristic, two correlations are calculated: r 2 : The correlation between DZ twin pairs on the characteristic (reflects a relatively small degree of genetic overlap).  r 1 > r 2 indicates that the personality characteristic is heritable. r 1 : The correlation between MZ twin pairs on the characteristic (reflects a relatively large degree of genetic overlap).

17. Psychology 30517  E.g., Computation of the heritability and environmentality of dominance using data obtained from a twin study: r 1 =.57 (MZ twins) r 2 =.12 (DZ twins) Heritability = 2 (r 1 – r 2 ) Environmentality = (1.00 – heritability) These results indicate that 90% of observed variance in dominance is due to individual differences in genetic makeup, whereas 10% of observed variance in dominance is due to individual differences in environmental factors. = 2 (.57 –.12) =.90 = 1.00 -.90 =.10

18. Psychology 30518 What personality characteristics are heritable? Temperaments Buss and Plomin (1984) define temperaments as personality characteristics that appear during the 1 st year of life, persist across the lifespan, have a pervasive influence on behaviour, and are highly heritable. These researchers have identified 3 distinct temperaments.

19. Psychology 30519 1.Activity level: Refers to the degree to which an individual expends physical energy through motor activity (reflected in intensity of behaviour and speed of action). 2.Sociability: Refers to the degree to which an individual prefers to be with others rather than be alone. 3.Emotionality: Refers to the degree to which an individual becomes physiologically aroused in upsetting situations. Buss and Plomin maintain that there are 3 components of emotionality: anger, distress, and fear.

20. Psychology 30520 EAS Temperament Survey Score on items: 2, 7, 10, 17 = Activity Level 1, 6, 15, 20 = Sociability 5, 8, 13, 18 = Emotionality: Anger 4, 9, 11, 16 = Emotionality: Distress 3, 12, 14, 19= Emotionality: Fear

21. Psychology 30521 EAS Temperament Survey Means and Standard Deviations (Naerde et al., 2004), N = 939 MeanSD Activity level3.10.69 Sociability3.76.60 Emotionality: Anger2.94.69 Emotionality: Distress2.33.72 Emotionality: Fear 2.22.60

22. Psychology 30522 Heritability statistics (Wlodzimierz et al.,2003): Activity level:.58 Sociability:.42 Emotionality—Anger:.62 Emotionality—Distress:.54 Emotionality—Fear:.70

23. Psychology 30523 The Big 5 Dimensions Research suggests that the dimensions of the Big 5 are heritable. Heritability statistics (Jang et al., 1998): Extraversion:.50 Agreeableness:.48 Conscientiousness:.49 Neuroticism:.49 Openness to Experience:.48

24. Psychology 30524 Personality Characteristics Related to Psychopathy Heritability statistics (Blonigen et al., 2003; Bouchard et al., 1990; Tellegen et al., 1988): Fearlessness …………………………………………… >.95 Carefree Nonplanfulness (i.e., impulsiveness)……....94 Machiavellianism (i.e., enjoys manipulating others)....74 Social potency (i.e., skilled at influencing others) …..66 Aggressiveness ………………………………………...67 Research suggests that characteristics related to psychopathy are heritable.

25. Psychology 30525 Heritability statistics (Bouchard et al., 1990; Tellegen et al., 1988) Creativity or imagination …………………………..74 Sense of alienation …………………………..........59 Traditionalism ……………………………………….59 Low risk taking ……………………………….........45 Achievement orientation …………………............38 Other Personality Characteristics Research suggests that there are a number of other characteristics that are heritable.

26. Psychology 30526 Case Example: Who was Phineas Gage? Phineas Gage was a 19 th century rail worker involved in construction in Vermont. In 1848, an accidental explosion blew an iron rod through his head. The rod was approximately 1.25 inches in diameter and 3 feet long. The rod entered under his left cheek and passed through his frontal lobes, ultimately exiting through the top of his head. Physiological Approach

27. 27 The Skull of Phineas Gage, 1823 - 1860

28. 28 Reconstruction of the Path of the Iron Rod Through Gage’s Skull

29. Psychology 30529 According to Gage's physician, Gage’s personality radically changed after the accident. His physician reported that: Gage was fitful, irreverent, indulging at times in the grossest profanity (which was not previously his custom), manifesting but little deference for his fellows, impatient of restraint or advice when it conflicts with his desires, at times obstinate, yet capricious and vacillating, devising many plans of future operations, which are no sooner arranged than they are abandoned in turn for others appearing more feasible. A child in his intellectual capacity and manifestations, he has the animal passions of a strong man. Previous to his injury, although untrained in the schools, he possessed a well-balanced mind, and was looked upon by those who knew him as a shrewd, smart businessman, very energetic and persistent in executing all his plans of operation. In this regard his mind was radically changed, so decidedly that his friends and acquaintances said he was “no longer Gage.” (Harlow, 1948)

30. Psychology 30530 Neurologist Antonio Damasio has written extensively on Gage. According to Damasio, Gage's story marks the historical beginnings of the scientific study of the physiological basis of personality.

31. Psychology 30531 Physiological Approach: What physiological theories of personality were proposed by early theorists? What physiological theories of personality were proposed by early scientists? One of the earliest recorded physiological theories of personality was proposed by Roman physician Galen in A.D. 170. Building on the work of Greek physician Hippocrates, Galen proposed the Bodily-Fluid Theory of Personality. This theory maintains that the amount of four fluids present in the body determine personality.

32. Psychology 30532  Excessive phlegm:  Excessive blood:  Excessive yellow bile:  Excessive black bile: Passive, calm, and thoughtful (i.e., phlegmatic) personality. Happy, outgoing, and optimistic (i.e., sanguine) personality. Unstable, aggressive, and irritable (i.e., choleric) personality. Unhappy, pessimistic, and somber (i.e., melancholic) personality.

33. Psychology 30533 Galen’s theory remained in favor for centuries. However, the theory fell out of favor with advances in physiology. An early, modern physiological theory of personality that was influential for some time was proposed by William Sheldon. His Somatotype Theory of Personality suggests that body type determines personality. Sheldon’s theory distinguishes between 3 body types:

34. Psychology 30534

35. Psychology 30535 Sheldon assigned individuals “somatotype ratings.” These ratings are comprised of 3 numbers, each ranging from 1 to 7. The numbers reflect an individual’s scores on the 3 dimensions of obese, muscular, and thin, respectively.

36. Psychology 30536 According to Somatotype Theory, the following characteristics are associated with each body type:  Ectomorph (“skinny”): Apprehensive, introverted, and restrained personality (cerebrotonia temperament).  Mesomorph (muscular): Assertive, adventurous, and bold personality (somatotonia temperament).  Endomorph (“fatty”): Sociable, relaxed, and fun- loving personality (viscerotonia termperament).

37. Psychology 30537 In contrast to Sheldon, most contemporary personality psychologists do not focus on global variables such as gross body type. Sheldon reported research findings to support his theory. However, efforts to replicate these findings were unsuccessful.

38. Psychology 30538 Today, the vast majority of researchers in this area employ measures of distinct physiological systems (e.g., heart rate). The primary goal of contemporary research is to identify differences in the physiological responses of individuals with distinct personality characteristics.

39. Psychology 30539 Questions That Were Answered in Today’s Lecture Biological Perspective on Personality: Behavioural Genetics Approach 1. What are the goals of behavioural genetics? 2. What are heritability and environmentality and how are they assessed? 3. What personality characteristics are heritable?

40. Psychology 30540 Physiological Approach 1.Case example: Who was Phineas Gage? 2.What physiological theories of personality were proposed by early scientists?