Role of Genetics and Environment in Determining Human Behaviour
📘 4.2 Role of Genetics and Environment in Determining Human Behaviour (मानव व्यवहार में आनुवंशिकता और पर्यावरण की भूमिका)
Human behaviour is the result of a complex interplay between two forces:
- 🧬 Genetics (Nature) — inherited biological traits
- 🌱 Environment (Nurture) — external influences like culture, family, education
🧬 I. Genetics (Nature)
📌 Definition:
Genetics refers to the biological inheritance passed through genes from parents to offspring. It influences:
- Intelligence
- Temperament
- Susceptibility to mental disorders
- Hormonal and neurological functioning
🧠 Psychological Examples:
- Identical twins reared apart still show remarkable similarities in IQ and personality.
- Disorders like schizophrenia, bipolar disorder, ADHD show higher concordance in genetically similar individuals.
🧬 Key Terms:
- Heredity – Transmission of traits (via DNA)
- Genotype – Genetic makeup
- Phenotype – Observable traits (influenced by both genes and environment)
🌱 II. Environment (Nurture)
📌 Definition:
Environment includes all external stimuli that affect development, such as:
- Family structure
- Education system
- Nutrition
- Peer influence
- Culture
- Economic status
📘 Indian Examples:
- A child raised in a multi-lingual home may develop higher verbal intelligence.
- Children in nutritionally deprived tribal areas show cognitive delays, even if genetically healthy.
⚖️ III. Nature vs. Nurture Debate
A central debate in psychology:
| Aspect | Genetics (Nature) | Environment (Nurture) |
|---|---|---|
| Focus | Inborn traits | Learned experiences |
| Theorists | Eysenck, Galton | Bandura, Skinner |
| Example | Intelligence inherited | Intelligence shaped by schooling |
Most psychologists today adopt an interactionist approach, recognizing that both nature and nurture contribute.
🧠 Famous Study:
- Minnesota Twin Study: Identical twins separated at birth still showed remarkably similar behaviours, supporting genetic influence.
- But their values, attitudes, and coping styles were shaped by upbringing, proving environmental influence too.
🧪 IV. Gene–Environment Interaction
This refers to how genes and environment work together to shape behaviour.
| Type | Explanation | Example |
|---|---|---|
| Passive interaction | Parents provide both genes and environment | Intelligent parents offer books + genes |
| Evocative interaction | Genetically influenced behaviour evokes a response | Sociable child gets more social input |
| Active interaction | Person seeks environment that fits genes | Creative child chooses art school |
🇮🇳 Indian Context Applications
- Ashram schools in tribal belts provide enriched environments → improving cognitive development.
- NEP 2020 promotes flexibility, recognizing each child’s unique genetic potential and learning style.
- NGOs like PRATHAM work on low-cost stimulation in underprivileged areas to offset environmental deficits.
📚 Psychological Theories
- Eysenck’s Trait Theory – Personality is biologically rooted
- Bandura’s Social Learning Theory – Behaviour is learned by observing others
- Bronfenbrenner’s Ecological Model – Emphasizes nested environmental systems from family to culture
✍️ Mains Answer Writing Format:
Intro: Define genetics and environment
Body:
- Explain each with examples
- Add a nature vs. nurture table
- Use Indian programs/studies (ICDS, NEP, Tribal research)
- Discuss gene-environment interaction
Conclusion: Adopt an interactionist approach
“Genes load the gun; environment pulls the trigger.”
🎯 Practice-Based Examples
- Case 1: A girl with high genetic IQ but no access to school → poor academic performance.
- Case 2: A boy genetically predisposed to aggression, but raised in a peaceful Gurukul environment → becomes a monk.
✅ Conclusion
The development of human behaviour is not determined by genes or environment alone, but by how the two interact over time. For policy and educational design, both factors must be considered to unlock human potential.
