Download Heredity and Environment

Heredity & Environment
Review
• Need for emergent theories?
• Sociocultural Theory
• Guided participation; zone of
proximal development
• Epigenetic Theory
• Nature vs. Nurture?
Gene Basics
•
DNA: molecule
containing
instructions for
protein manufacture
•
Chromosome: 46
(23 pairs) of DNA
molecules
•
Gene: Section of
chromosome; basic
unit of heredity
Conception
• Zygote: living cell formed by 2
gametes (ovum & sperm)
• Genotype created
• Entire genetic inheritance
• Phenotype: genetic expression
• Is phenotype present at
conception?
Female or Male?
•
XX
•
XY
Genetic Influence
• Most human characteristics are polygenic
& multifactorial
• 99% of human genes present in genomes of
other organisms
• Exceedingly complex interaction between
genes, and between environment and genes
• Behavioral genetics: study of extent to
which behavioral characteristics are due to
genetic or environmental influences
Behavioral Genetics
•Genes are passed along
from parent to child
• “Like father, like son”
• “A chip off the old block”
• “The apple doesn’t fall far
from the tree”
Behavioral Genetics
•Much of human behavior is influenced by
genetics
• Finger crossing
• Ability to roll tongue
• Handedness
• Likelihood of wearing sunglasses
Psychological Study of
Heredity
• Twin studies
• Monozygotic (MZ) twins
• Dizygotic (DZ) twins
Conclusions from Twin
Studies
1. Genes affect every aspect of human
behavior.
2. Most environmental influences of kids
raised in same home are not shared.
3. Kids’ genes influence others’ responses.
Kids’ environment is shaped by their genes.
4. Choose environments compatible with
genes, thereby increasing genetic
influences in adulthood.
Environment
•Everything that is
not nature
• Peer influence
• Family influence
• Wealth or poverty
• Temperature
• Culture
• Education
Parental Influence
•Freudian theories and
pop culture of the 1990s
= blame your parents
• (especially mom)
•Other environmental
influences play a bigger
role
Peer Influence
•Children and adults fit into
groups by conforming
•Examples of peer influence:
• Accents
• Food choices
• Health behaviors
•Parental influence and peer
influence are complementary
Cultural Influence
•Culture:
Behaviors, ideas,
attitudes, & traditions shared
by a large group of people
and passed on to future
generations
•Cultural Norms: rules for
accepted & expected behavior
Experience Affects Brain Development
Impoverished
environment
Rat brain
cell
Enriched
environment
Rat brain
cell
http://learn.genetics.utah.edu/content/epigenetics/nutrition/
Gene-Environment
Interaction
•Nature (genes) set a potential
range
•Nurture (environment) determine
where within that range
•Examples:
• Height
• Athletic ability
• Personality
• Environmental influence on heredity
• What conclusions do you draw from
Dr. Ornish’s talk?