INTRODUCTION
Before we can measure intelligence we must first of all define what we mean by intelligence? And that is the problem. Different people have different ideas on the nature of intelligence and how it might differ from one's ability to remember and recall knowledge, or from one's ability to apply knowledge to change the physical world.
The desire to measure an individual's intelligence is eventually a desire to classify people. This might be an abstract interest, but it may also stem from an employer's interest to select employees who are going to succeed.
And if we are interested in extending our sphere of interest to possible extraterrestrial intelligence, we then can speculate on how we might compare these creatures against humans.
DEFINITIONS OF INTELLIGENCE
There are several theories of intelligence each with their definitions or lists of intelligence(s).
The triarchic theory of intelligence believes there are three types of intelligence:
In 1983 Howard Gardener, and American Psychologist proposed a list of eight or nine intelligences:
An unusual list of intelligences is:
A different approach lists the "components" of general intelligence as:
Psychologists also classify intelligence into two categories, fluid and crystallised. Fluid intelligence is the ability to solve multiple unrelated problems. Crystallized intelligence is the ability to solve similar problems quickly.
MEASURING INTELLIGENCE
Intelligence tests all have in common an attempt to find a single number that measures general intelligence or a measure of a person's mental capacity and ability. Historically this number is called IQ and it is standardised so that the IQ of a group around the same age has a mean value of 100 and a standard deviation of 15.
The first IQ test was developed by Alfred Binet in 1905. It is still used in a modified form called the Stanford-Binet test and supposedly measures:
Another widely used test is the Wechsler Adult Intelligence Scale (WAIS) and the Wechsler Intelligence Scale for Children. These assess a variety of verbal and performance subtests, giving a full-scale IQ and individual scores in areas like verbal comprehension and perceptual reasoning. It produces a general score and 2 and 4 subscores as shown in the diagram below.
One of the criticisms of the above tests is that they all have cultural bias. The questions are in English and directed toward an education that might expected in English schools. This problem would be even more acute for a species that has developed away from Earth.
In 1930, Raymond Cattell developed an intelligence test that he thought would be free of cultural bias. This is called the Cattell Culture Fair Test. It supposedly tests inductive reasoning skills in the category of fluid intelligence. Some examples are given below.
There are many 'IQ' tests and psychometric tests available on the web and in books. These are all useful for practice if you wish to improve your ability to do these sorts of tests and to see the variety of questions that you might encounter. You might also like to think upon the question of determining the intelligence of an alien race.
Australian Space Academy