मराठी

Genetic Bases of Development - Personality

Topics

Estimated time: 13 minutes

Introduction
Heredity and Behaviour
Twin Studies
Personality Traits Related to Heredity
Real-Life Application
Key Points: Personality

CISCE: Class 12

Introduction

Personality refers to the combination of thoughts, feelings, and behaviors that make each person unique. Heredity means the passing of traits from parents to children through genes and chromosomes. Psychologists believe that heredity plays an important part in shaping certain aspects of personality, such as temperament and emotional tendencies. However, environment and life experiences also influence how these inherited traits are expressed in real life.

CISCE: Class 12

Heredity and Behaviour

Scientists have tried to find out whether heredity influences behaviors such as aggression, introversion, and extraversion.
The results show that:

Some people show repeated acts of violence or aggression, which may have a biological link.
A study of very tall male prisoners found that about 10% had 47 chromosomes (XXY or XYY) instead of the normal 46.
In the general public, such an abnormality is present in only 1% of people.

This suggests heredity may influence some tendencies, but genes alone cannot explain behavior. Life experiences, family environment, and social factors play important roles.

CISCE: Class 12

Twin Studies

To understand how much behavior is affected by genes, psychologists compare identical twins and fraternal twins.

Results show that some traits, like shyness or sociability, have genetic roots, though the environment affects how they grow.

CISCE: Class 12

Personality Traits Related to Heredity

Research suggests heredity partly influences these personality traits:

Introversion: Being quiet, thoughtful, and shy.
Extraversion: Being lively, outgoing, and friendly.

These traits are part of Eysenck’s biological theory of personality, where genetics and environment together shape who people become.

CISCE: Class 12

Real-Life Application

Two brothers brought up in the same home may still be different:

One enjoys parties and talking to people (extrovert).
The other prefers staying alone and reading (introvert).

Though their environment is the same, their genetic makeup creates differences in behavior.

CISCE: Class 12

Key Points: Personality

Personality is shaped by both heredity (genes) and environment (experiences and upbringing).
Heredity influences traits like temperament, introversion, and extraversion.
Studies show some behaviours, like aggression, may have biological links, but the environment also plays a role.
Twin studies show that identical twins are more similar, supporting a genetic influence on personality.
Hans Eysenck explained that personality develops through the interaction of heredity and environment.