Heredity and Environment
Introduced| English |
|---|
| genes/dʒiːnz/ |
| environment/enˈvaɪrənmənt/ |
| Heredity/həˈredɪti/ |
| evolutionary perspective/ɪvəˈluːʃənəri pəˈspektɪv/ |
| natural selection/ˈnætʃərəl sɪˈlekʃn/ |
| Twin studies/twɪn ˈstʌdiz/ |
| Adoption studies/əˈdɒpʃn ˈstʌdiz/ |
| Family studies/ˈfæmɪli ˈstʌdiz/ |
Two identical twins, two different lives
- Identical twins share the same genes 基因, yet they never turn out exactly the same.
- Something other than genes must be acting on them.
- That something is environment 环境 — everything that happens to a person.
Heredity and environment interact
- Heredity 遗传 is what is passed down biologically from parents.
- The CED's claim is that the two interact — neither works alone.
- Height is inherited, but poor nutrition lowers it. The gene sets a range; the environment picks a point inside it.
Heredity, environment, or the interaction?
Sort each piece of evidence by what it points to.
The CED's position on heredity and environment is that they...
Heredity and environment interact; the gene sets a range and conditions pick a point inside it.
The evolutionary perspective
- The evolutionary perspective 进化论视角 asks how natural selection 自然选择 shaped behaviour.
- A behaviour that helped ancestors survive and reproduce is more likely to appear today.
- Fear of snakes is learned unusually fast — plausibly because slow learners left fewer descendants.
The ____ perspective explains behaviour by asking what helped ancestors survive and reproduce.
The evolutionary perspective applies natural selection to behaviour and mental processes.
Never write that a trait is "caused by genes" or "caused by upbringing". The CED's position is that heredity and environment interact, and an exam answer that picks one side has taken a position the course rejects.
Select all the research designs the CED names for separating heredity from environment.
Twin, adoption and family studies vary how much DNA and how much environment people share.
Match each design to what it varies.
Each design holds one thing constant and varies the other, so the two sources can be told apart.
How researchers separate the two
- Twin studies 双生子研究 compare identical twins with fraternal twins.
- Adoption studies 收养研究 compare children with their biological and adoptive parents.
- Family studies 家族研究 track a trait through relatives who share different amounts of DNA.
If identical twins raised apart are still similar on a trait, that points to heredity.
Same genes, different environments — so the remaining similarity is evidence for heredity.
Reading a twin study
- If identical twins raised apart are still alike on a trait, heredity matters for it.
- If identical twins raised together differ, environment matters for it.
- Neither result ever proves that one side acts alone — it only shows how much each contributes.
Two brothers are both tall. Their father is tall, so heredity contributes. But the younger brother, who grew up after the family's income rose, is 5 cm taller than his sibling — environment picked a different point inside the same inherited range.
Heredity and environment always interact. The evolutionary perspective explains behaviour by what helped ancestors survive. Twin, adoption and family studies are how psychologists estimate how much each side contributes.