Spearman's two factor theory of intelligence
Giving a proper definition of intelligence has been debatable. Different psychologists have different views on
intelligence. Spearman considers intelligence as a general capacity of the individual to think rationally and
problem solving.
The two factor theory of intelligence was proposed by Charles Edward Spearman a famous British psychologist.
His career began in the army serving 15 years and then retired and pursed a PHD in experiment psychology.
Spearmen went to university of Leipzig that is located in Germany under Wilhelm Wundt. He was the first to
use mathematical methods to understand, interpret, and analyse the human brain.
He examined various mental aptitude and cognitive tests taken by the participants to develop this theory. During
assessment, he noticed that the scores of same participants were consistent across all tests. i.e., an individual
who achieved high scores in one aptitude test got similar scores in other aptitude tests and individual who got
low scores in one aptitude test got low in other tests too. This led him to conclude that there’s a strong link
between overall intellectual capability and how people perform on various mental tasks.
In the process of studying the components of intelligence, Spearman used a statistical method called factor
analysis to analyse the relationship between the components of intelligence and the scores of various types of
tests. He noticed that those scores weren’t random, they were grouped in a manner indicating a shared factor
affecting the performance on various cognitive tests. This shared element is known as g factor. Essentially, “g”
represents a measurable quality that explains why some people perform well across a range of mental abilities.
In addition, different people also had different scores in different areas, and these differences were considered to
reflect the existence of a special component of human intelligence called the S-factor.
From Spearman’s Point of view, you can imagine intelligence as a dish with two major ingredients. These are:
1) General Factor(G-Factor): It includes mental operations which are primary and common to all
performances. The g factor for general intelligence refers to the capacity for reasoning and problem-
solving. G factor would most likely be measured by a regular IQ test. Spearman observed that there is a
tendency for a variety of cognitive tasks and intellectual measurements to be associated with one
another, meaning that those who perform well on one would likely perform well on the others.
Example: You can read.
2) Specific factor(S-Factor): The s factor takes into account differences in certain skills. Task-specific
skills in particular domains, like music, business, or the arts, are called specific intelligence factors.
They refer to specific skills related to memory, vocabulary, numeracy, and spatial imagery, among
other things. G-factor also plays a role in determining s-factors. It includes specific abilities which
allow individuals to excel in their respective domains
Example: How good you are at reading
Criticisms:
According to Thurstone and Guilford intelligence is made up of more than two factors
According to Thorndike, the inter correlation studies by Spearman were too small to test the question
of a common factor. Therefore opposed the existence of general intelligence
In conclusion, this theory highlights the dual nature of intelligence, combining a broad, general ability with
specialized, task-specific skills. It has laid the groundwork for intelligence testing and research in cognitive
psychology. Spearman provided a lot of evidences in support of the g and s- factor on the basis of
correlation method. On the basis of these studies he told that higher the involvement of g-factors within two
mental work higher the value of correlation.
