6.4 Heredity and Environment
1.) Body Build 5.) Baldness
2.) Intelligence 6.) Handedness
3.) Personality 7.) Height
4.) Mathematical 8.) Musical ability
ability 9.) Longevity
Nature vs. Nurture
• John Watson, the founder
• Sir Francis Galton published
of behaviorism, wrote in
Heredity Genius in 1869:
1930: Give me a dozen
after studying the families
healthy infants, well-
of over 1000 successful
formed, and my own
families he concluded that
specified world to bring
success ran in families and
them up and I’ll guarantee
heredity was the cause.
to turn him into any
specialist-doctor, lawyer,
artist etc.
• Heredity: the genetic transmission of
characteristics from parents to their offspring.
• Identical Twins: twins who come from one
fertilized egg; twins having the same heredity.
• Genes: the basic building blocks of heredity.
• Fraternal Twins: twins who come from two
different eggs fertilized by two different
sperm.