Twin studies

Question 1

Define monozygotic and dizygotic twins

Answer 1

M: 100% of DNA is identical
D: share 50% of DNA

Question 2

Thorndike 1905

Answer 2

• first psych tests using twins
• 50 pairs of twins to explore why twins resemble each other in regard to mental traits
• theory: no greater than siblings in same environment, grow more alike till leave home, greater on tasks subject to training
• findings: no strong evidence that environment is responsible, some to support trained tasks

Question 3

2 types of twins

Answer 3

Curtis Merriman
Fraternal: of 2 egg origin = no greater resemblance than ordinary twins
Duplicate: of 1 egg origin = show higher degree of resemblance

Question 4

Cyril Burt study findings

Answer 4

higher correlation coefficient for intelligence for MZ twins raised together, than MZ apart, siblings together

Question 5

Researchers accept

Answer 5

• both heredity and environment interact in various ways and contribute to intelligence
• extreme enriched environments can interfere with realization of a persons intelligence

Question 6

Bouchard and McGue

Answer 6

• looked at genetic and environmental influence on human psychological differences including general intelligence (g)
• findings: higher genetic influence for abilities