Personality Psychology

Brent W. Roberts

University of Illinois at Urbana-Champaign

What is Personality?

• Broadly speaking it has to do with how each of us is:

• Different from everyone else

• Similar to some people

• The same as all humanity

• Specifically….

Reputation: Observations Unconscious processes

Roles: Status Affiliation Intimacy

Identity: Self-reports Conscious, subjective experience

Traits Big Five Positive & Negative Affect Attachment Styles

Motives & Values Goals Interests Life tasks

Abilities g Verbal, Spatial, Quantitative

Narratives Stories Significant memories Scripts Ideological settings

Society/Culture

Units of Analysis

Genes

Physio-Logical Mechanisms

Fulcrum of assessment Distal causesDistal causes

How did you get your personality?

Genes? Experience? Both?

Heritability of Personality Traits

1. Most personality traits have a heritability between .3 to .5

2. Personality is only weakly influenced by “shared” family environment (social class, child-rearing styles, religion, etc.)

3. Personality is more strongly affected by nonshared environment (accidents, sibling interaction, influences outside of family).a. Effects replicate for Monozygotic twins raised apart.b. Average personality trait correlation among adopted siblings is

near zero.c. Average personality trait correlation between parents and

adoptive children is often near zero.d. Average personality trait correlation between parents and

biological offspring is very small.

Moving from behavior genetics to the genome.

1. Are there specific genes that affect personality?a. Wrong question.

2. Correct question: How do genes interact with environments to determine personality (Caspi et al., 2002 & 2003)?

3. Are you a delinquent?a. Don’t conform to social normsb. Break lawsc. Dishonestd. Violent & aggressivee. Consistent irresponsibilityf. Low agreeableness and conscientiousness

What are the genetic and environmental links?

1. MAOA gene. Encodes the MAOA enzyme which metabolizes neurotransmitters such as norepinephrine, serotonin, and dopamine.

2. Low MAOA activity is associated with elevated aggression.

3. Childhood maltreatment is associated with delinquency in adolescence.

Caspi et al., (2002).

1. Examined interaction between genetic variation in MAOA gene (low and high activity) and childhood maltreatment on delinquency.a. MAOA gene was unrelated to delinquency.b. Boys who had the low activity gene who were severely

maltreated committed more delinquent acts in adolescence (violent offenses, antisocial personality disorder).

c. Boys who had high activity gene who were severely maltreated committed no more delinquent acts than boys who were not maltreated.

Percent diagnosed with conduct disorder as an adolescent

0

10

20

30

40

50

60

70

80

90

Low MAOA activity High MAOA activity

No MaltreatmentSevere Maltreatment

Why should we care? Because who we are determines what we do….

Children who were rated as more conscientious when they were 8 lived longer than their counterparts (Friedman et al., 2003).

People who are more conscientious as adolescents experience higher levels of occupational success by age 50 (Judge et al., 1999).

People who are more conscientious in college have more children and fewer divorces at age 40 (Roberts & Bogg, 2004).

People who are more anxious at age 18 had lower relationship satisfaction across different relationships at age 21 and age 26 (Robins et al., 2002).

People who are more creative in college experience higher levels of success in creative occupations 30 years later (Helson, Roberts, & Agronick, 1995).

Now that you have a personality are you done developing?

No.

Roberts & Walton (under review)

98 longitudinal studies that tracked mean-level changes in personality traits in 104 different samples.

47,340 participants that ranged in age from 10 to 101.

d-scores were used to estimate change.

M2-M1/SDp

How much mean-level change do personality traits demonstrate across the life course?

Meta-Analytic Estimates of Change in Social Vitality

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

Ch

ange

in

Soc

ial

Vit

alit

y

10 to18 (10)

18 to22 (15)

22 to30 (22)

30 to40 (11)

40 to50 (16)

50 to60 (8)

60 to70 (6)

70 + (6)

*

Roberts & Walton (under review)

*

Meta-Analytic Estimates of Change in Social Dominance

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Cha

nge

in S

ocia

l Dom

inan

ce

10 to 18(5)

18 to 22(9)

22 to 30(14)

30 to 40(6)

40 to 50(5)

50+ (4)

*

*

Roberts & Walton (under review)

* *

Roberts & Walton (under review)

Meta-Analytic Estimates of Change in Agreeableness

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Cha

nge

in A

gree

able

ness

10 to 18(17)

18 to 22(11)

22 to 30(17)

30 to 40(9)

40 to 50(11)

50 to 60(5)

60+ (5)

*

Meta-Analytic Estimates of Change in Conscientiousness

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Cha

nge

in C

onsc

ient

ious

ness

10 to 18(15)

18 to 22(17)

22 to 30(21)

30 to 40(9)

40 to 50(10)

50 to 70(8)

60 + (4)

*

*

*

Roberts & Walton (under review)

*

Meta-Analytic Estimates of Change in Emotional Stability

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

Cha

nge

in E

mot

iona

l St

abil

ity

10 to18 (19)

18 to22 (15)

22 to30 (31)

30 to40 (15)

40 to50 (21)

50 to60 (10)

60 to70 (8)

70+ (8)

*

*

**

Roberts & Walton (under review)

Meta-Analytic Estimates of Change in Openness to Experience

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

Cha

nge

in O

penn

ess

10 to18 (11)

18 to22 (37)

22 to30 (12)

30 to40 (8)

40 to50 (7)

50 to60 (4)

60 to70 (4)

70+ (4)

*

*

Roberts & Walton (under review)

*

Aggregate Change in Personality Traits Across the Life Course

-0.7-0.5-0.3-0.10.10.30.50.70.91.11.3

10 to18

18 to22

22 to30

30 to40

40 to50

50 to60

60 to70

70+

OpennessEmotional StabilityConscientiousnessAgreeablenessSocial DominanceSocial Vitality

Why should we care about this?

In a follow-up to their earlier work, Friedman et al., found that childhood conscientiousness and adult conscientiousness predicted longevity independent of one another.

The changes we experience in adulthood may have significant consequences for our health and well-being.

What causes us to change in adulthood? Social Investment Hypothesis:

Personality changes arise through experiences in universal tasks of social living, such as establishing one’s social position in society through one’s work or forming long-term bonds through the creation of a family unit in young adulthood (Helson, Kwan, John, & Jones, 2002).

The Social Investment Hypothesis

InvolvementIn work at age 26

Increases in ConstraintFrom 18 to 26

.25*

Percentage ofTime marriedFrom 43 to 52

Increases in ResponsibilityFrom 43 to 52

.18*

SmokingMarijuana at Age 43

Decreases in ResponsibilityFrom 21 to 43

.34*

Personality is an exciting, complex, and dynamic field

Behavior genetics

Genomics

Development

Health & Longevity

Conclusions