Levels of Intelligence - Age and Intelligence

Topics

Introduction
Intelligence Growth Over the Lifespan
Distribution of IQ in the Population (Normal Curve)
Real-Life Application
Key Point Summary

CISCE: Class 12

Introduction

Intelligence refers to the ability to learn, reason, solve problems, and adapt to new situations. It includes skills such as logical thinking, creativity, and understanding complex ideas.

CISCE: Class 12

Intelligence Growth Over the Lifespan

CISCE: Class 12

Distribution of IQ in the Population (Normal Curve)

IQ Range	Category	Approx. % Population
>130	Very superior	2.2%
120–129	Superior	6.7%
110–119	High average	16.1%
90–109	Average	50%
80–89	Low average	16.1%
70–79	Borderline	6.7%
<70	Intellectually disabled	2.2%

CISCE: Class 12

Real-Life Application

Think of growing intelligence like learning to ride a bicycle:

As a child, you wobble and learn quickly (unstable, then rapid growth).
By your teens, you can ride smoothly and confidently (peak).
In adulthood, you maintain your cycling skills at a steady level for years (plateau).
Later in life, you might ride more slowly or need support (decline).

CISCE: Class 12

Key Point Summary

Intelligence develops steadily from childhood and peaks between 16–20 years old.
Stays stable during young and middle adulthood (up to about 45 years).
Shows a slow decline in later adulthood.
In the general population, IQ scores form a bell curve, with most people scoring near the average.