Understanding Psychology (10th Ed)

 
Module 26 
What Is Intelligence? 
287
Assessing Intelligence
Given the variety of approaches to the components of intelligence, it is not surprising 
that measuring intelligence has proved challenging. Psychologists who study intel-
ligence have focused much of their attention on the development of  intelligence tests 
and have relied on such tests to quantify a person’s level of intelligence. These tests 
have proved to be of great benefi t in identifying students in need of special attention 
in school, diagnosing cognitive diffi culties, and helping people make optimal educa-
tional and vocational choices. At the same time, their use has proved controversial, 
raising important social and educational issues.
Historically, the fi rst effort at intelligence testing was based on an uncomplicated 
but completely wrong assumption: that the size and shape of a person’s head could 
be used as an objective measure of intelligence. The idea was put forward by Sir 
Francis Galton (1822–1911), an eminent English scientist whose ideas in other domains 
proved to be considerably better than his notions about intelligence. 
Galton’s motivation to identify people of high intelligence stemmed from per-
sonal prejudices. He sought to demonstrate the natural superiority of people of high 
social class (including himself) by showing that intelligence is inherited. He hypoth-
esized that head confi guration, which is genetically determined, is related to brain 
size and therefore is related to intelligence. 
Galton’s theories were proved wrong on virtually every count. Head size and 
shape are not related to intellectual performance, and subsequent research has found 
little relationship between brain size and intelligence. However, Galton’s work did 
have at least one desirable result: He was the fi rst person to suggest that intelligence 
could be quantifi ed and measured in an objective manner (Jensen, 2002).