The Psychology Book

I

n 1859, Charles Darwin set

out his theory of evolution

in On the Origin of Species,

providing a framework for the

debate over whether intelligence

was fixed by genetic inheritance, or

could be modified by circumstances.

His cousin, Francis Galton, carried

out tests on the cognitive abilities

of around 9,000 people in London

in the early 1880s, and concluded

that basic intelligence was fixed

at birth. Around the same time,

Wilhelm Wundt proposed the idea

of an intelligence quotient (IQ),

and made attempts to measure it.

Wundt’s work inspired studies into

the measurement of mental abilities

by the American psychologist

IN CONTEXT

APPROACH

Intelligence theory

BEFORE

1859 English naturalist

Charles Darwin proposes

that intelligence is inherited

in On the Origin of Species.

From 1879 Wilhelm Wundt

applies scientific methods to

psychology, seeking objective

ways of measuring mental

abilities such as intelligence.

1890 US psychologist James

Cattell devises tests to

measure differences in

individual mental abilities.

AFTER

1920s English educational

psychologist Cyril Burt claims

intelligence is mainly genetic.

1940s Raymond Cattell defines

two types of intelligence: fluid

(inborn) and crystallized

(shaped by experience).

T H E I N T E L L I G E N C E

OF AN INDIVIDUAL

IS NOT A FIXED

Q U A N T I T Y

A L F R E D B I N E T (1857–1911)

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