Our mental age

By Alex P. Vidal

“I keep six honest serving men. They taught me all I knew. Their names are What and Why and When and How and Where and Who.” —Rudyard Kipling

JULY 8 happens to be the birthdate of Alfred Binet (July 8, 1857-October 18, 1911), the man who organized a system of tests which were not based on school information but rather on general mental abilities.

Binet’s work eventually laid the basis for the many tests of intelligence we have today.

I learned after reading the High Points in Biology that to measure a person’s intelligence, he or she is given one or more of the intelligence tests which have already been “standardized” in the way just described. His result on the test gives his “mental age” (M.A.).

For example, if a child does as well on a certain test as the average 12-year-old, he has a mental age of 12. If the child actually is 10 years old, his “chronological age” (C.A.) is 10.

The child’s I.Q. is then found by dividing his mental age by his chronological age.

A person whose mental age is the same as his chronological age, has normal or average intelligence. His I.Q. is 100.

The following table shows how people are classified by their I.Q.’s in each I.Q. “bracket,” according to High Points in Biology:

I.Q. 140 or over– classification is genius; 120-140: very superior; 110-120: superior; 90-110: normal; 80-90: dull normal; 70-80: borderline normal; 50-70: moron; 25-50: imbecile; below 25: idiot.


Knowledge, according to Sir Francis Bacon, is power. Intelligence, on the other hand, has other definition.

Most psychologists consider intelligence to be “the ability to adjust properly to the environment” particularly when faced with new problems or situations.

In other words, intelligence is the ability to use the knowledge we have in order to “figure out” what to do in a new situation.

But here’s why intelligence is reportedly much different from knowledge.

A two-year-old child knows very little, because he hasn’t had enough time to acquire the knowledge of a grown-up; but he may be very intelligent in the way he uses the little knowledge he has.

In the same way, a person who has had little chance for education may be highly intelligent, yet unable to read and write.

Special tests are used to measure intelligence. These are not information quizzes, but tests of the individual’s powers of memory, judgment, reasoning ability, etc.

Before an intelligence test can be used, it must be tried out on thousands of individuals.

From the results the test psychologist finds out how well the average person of a given age makes out on the test. The test is then ready for use.


The measurement of a person’s intelligence was done after the Bureau of Education in Paris wanted to find out whether the poor results of many children were due to inattentiveness, lack of desire to learn, or lack of intelligence or ability to learn.

Many mental traits and talents seem to be controlled at least partly by genes, research showed.

The histories of several families reveal a high percentage of individuals with such exceptional mechanical ability that it is universally recognized and respected.

Peculiarly enough, unusual mechanical ability has been found in feeble-minded individuals, indicating that intelligence is not necessarily related to other talents.

Musical talent seems to be controlled by heredity. However, it seems that many genes must appear together to produce a truly great musical genius.

This probably explains why there are so few great composers and performers, and why they sometimes appear among families where no unusual musical ability appeared before. The Bach family is an example of a family with many musical members.

Unfortunately, no accurate studies of this characteristic have been made, but most investigators are agreed that this characteristic may have a genetic basis.

(The author, who is now based in New York City, used to be the editor of two daily newspapers in Iloilo.—Ed)