Lecture 7: Genetic versus Family Influences on Personality Flashcards
What is an heritability quotient?
It is an estimate of the proportion of variability of a given characteristic that can be attributed to genetic differences between people.
How did we find if personality traits were heritable?
Fraternal and identical twins were studied. It was found that Fraternal twins shared 50% (like siblings) and identical 100% of the traits.
What is the average correlation for identical twins (MZ) for extraversion?
- Approximate heritability: 50%
Given the results for identical twins, could it be that they have similar personality given that they are treated similar?
No, in a study, they looked at twins that were raised apart vs raised together, where apart had r=0.49 and together r=0.52
So the shared environment only accounts for a small amount of variance and thus, it looks like it comes from the genes.
What is Locus of Control?
Refers to an individual’s perception about the underlying main causes of events in his/her life
Is there a correlation between genes and Locus of Control?
No, but living together does.
What gene is responsible for personality traits?
There is no gene found yet, and the current theory is that it is not a single gene but a combination of genes that shape the personality traits.
What is a non-shared environement?
The aspects of the environment that operate and influence the members of a family unalike.
Which are some of the non-shared family effects?
- Birth order
- Distinct life events
- Influences outside of the family
Is your birth order related to your Big 5 traits?
NOOOO!
Which study looked into correlation between Big 5 traits and birth order?
- Study by Jefferson, Herbst and McRae
- 10 000 adults
- Looked at the Big 5 traits and birth order
- Controlled for SES, gender
Is parenting a bit aspect of development of personality traits?
No, genes is the most important one. Shared environment does not make an impactful difference.
Besides genes and non-shared environment what else could affect personality traits?
Life events can affect the personality traits. In particular in a Swedish study, 20000 participants (all identical twins), if one of the twins had a specially stressful life, their neuroticism levels would be higher than the other twin.
