Temperament

Temperament

Traits related to

• emotion expression and reactivity (how strong of emotions do they feel)

• Activity (how physically active)

• Attention/focus (how long do you stay on one task)

“Constitutional”/ early appearing/ biological

Focus on individual difference

Rothbart and Bates (IBQ/CBQ)

Five dimensions

1. Fear/fearful distrust

2. Distress at limitations/ irritable distress

3. Attention span/ focus/ persistence

4. Activity level

5. “Smiling and laughter”/ positive affectvity

Effortful control/ regulation (appears 2-3 years)

Fear/ fearful distrust

Afraid of new things/ people/ places/ noises/ changes

Distress at limitations/ irritable distress

How upset they are at having to wait for something

Strapped in chair

Attention span/ focus/ persistence

How long do they sit with a picture book/ play with something

How long can they work on something

Activity level

Infants: moving around in crib

Effortful control/ regulation

Beginning executive function traits

Three types of children (Thomas & Chess)

Easy child (40%)

Difficult child (10%)

Slow-to-warm-up (15%)

Easy child

High in positive affectivity

Easy recovery from distress

Regular routines

Difficult child

High in fearful distress/ slow to adjust to new experiences

React negatively and intensely when distressed

Irregular routines

Slow-to-warm-up

Low activity, low-key reactions to environment

Low in positive affectivity

High in fearful distress/ inhibited

Eventual adjustment (after repeated exposure)

Outcomes of study

70% of “difficult” children developed behavior problems by school age

50% of “slow to warm up” children showed adjustment problems in middle school

18% of “easy” children developed such problems

Dunnedin study

Negative, unregulated children (Casp, Moffitt, & colleagues)

• as adolescents

  • deliquncy

• As 21 year olds

  • living partners: didn’t get along

  • unemployed

  • Less social support

  • Anxiety

  As 31-year-olds

  • Poor health

  • Less wealth

  • Higher substance use

  • Criminality, gambling

Behavior genetics

MZ and DZ twins

Heritability

The extent to which individual differences can be explained by genetic differences

=2(r(MZ)-r(DZ))

Shared environment

Environmental differences between families (shared by family members)

r(MZ) - heritability

Non-shared (unique environment)

Environmental differences within families

Treat children differently, different teachers, friends, sports, sickness

1-r(MZ)

Genetics of temperament

Heritability (infants) = 0.36

Shared environment = 0

Non-shared environment = 0.64

Another twin study of temperament

Moderate to large heritability

Moderate to large non-shared environment

No share environment

Passive gene-environment correlations

Lemery-Chalfant et al measured home environment

CHAOS scale (confusion, hubbub, and order scale)

LEOS scale (living environment observation scale)

• Physical safety, home decor, child-friendliness, adequate living space, organization, outside play environment, street condition

Passive gene environment correlations

The home environments themselves were heritable and correlated with child traits

Parents created the home environment using genes they share with their child = passive rGE (gene environment)

Home environment is correlated with genes, so it can’t be separated from heritability

Shared environment is also heritable

“Goodness of fit” model (Thomas & Chess)

Occurs when parents/adults create child-rearing environments that recognize each child’s temperament while encouraging more adaptive functioning

Evocative gene-environment correlation

Doesn’t change temperament but “encourages more adaptive functioning”

Gene-environment interactions

Child who is not inhibited has a middle level of internalizing disorders

Highly inhibited child is less susceptible to insensitive parenting