## Just a Number? The Science and History of IQ, Part 1

Who was smarter--Galileo or Mozart?

Answering that question seems impossible. After all, the former was an astronomer, the latter, a composer. Asking which of the two was smarter seems akin to forcing someone to objectively determine if apples are better than oranges. But while humans have not yet invented a scale to measure the value of fruit, we do have one that measures brain-power: the IQ test. And according to a book by Stanford psychologist Catherine Cox Miles, Galileo's IQ was around 20 points higher than Mozart's. The number may seem trivial, but if both of them were three-years-old today, competing for a slot at a private New York City preschool, Galileo would likely edge out Mozart. But should he? Is there such a thing as a true measure of something as intangible as intelligence?

The notion of assigning a numerical value to intelligence dates back to the early 20th century, when French psychologist Alfred Binet created a series of tests to help Parisian public schools identify "mentally defective" children. Between 1904 and 1911, Binet and his colleague Theodore Simon observed the skills of "average" French schoolchildren, then created a series of tests for students between the ages of three and 12 designed to assess whether their abilities were above or below the norm.

To calculate a student's "intelligence quotient," Binet and Simon simply took his mental age, divided it by his actual age, and then multiplied by 100. For example, if a seven-year-old could perform the tasks required of a nine-year-old, his IQ would be (9 / 7) *100, or around 128.

Intelligence testing reached the United States in 1916, when psychologist Lewis Terman created a new, refined intelligence scale based on the abilities of thousands of students--significantly more than the fifty or so Binet studied. Today, psychologists use a revised version of Terman's scale to evaluate children in five categories: fluid reasoning, knowledge, quantitative reasoning, visual-spatial processing and working memory. Big differences in a student's scores across these categories can help psychologists diagnose learning disabilities.

Try to answer some questions from a real IQ test yourself. Below are some examples, one from each of the five categories.

Fluid Reasoning:
1. "I knew my bag was going to be in the last place I looked, so I looked there first." What is silly or impossible about that?

Knowledge:
2. What does cryptic mean?

Quantitative Reasoning:
3. Given the numbers 3, 6, 9, 12, what number would come next?

Visual-spatial Processing:
4. Suppose that you are going east, then turn right, then turn right again, then turn left. In what direction are you facing now?

Working Memory:
5. Repeat a series of digits (forward or backward) after hearing them once.

Source: Introduction to Psychology by Dennis Coon and John O. Mitterer

Just a few years after Terman brought the IQ test to the United States, it left the classroom--and entered the military. During World War I, the number of army recruits exploded from around 200,000 in March of 1917 to over 3.5 million in November of 1918. As the military grew, so too did the need for trained officers; the most intelligent recruits needed to be identified early so they could enter officer training programs.

Thus Harvard psychologist Robert Yerkes developed the Army Alpha and Beta tests. Modeled after the Stanford-Binet scale, the tests were designed to give commanders a sense of the intelligence of the men they were leading and to screen soldiers for officer potential. Unlike Terman's IQ test, the army exams could be administered to recruits en masse and the results could be summed and interpreted without the expertise of a psychologist. During WWI, over 1.7 million men took the intelligence tests.

Think you have what it takes to be an officer? Try the questions below--they appeared on real Army alpha tests.

1. If you saw a train approaching a broken track you should:
A. telephone for an ambulance
B. signal the engineer to stop the train
C. look for a piece of rail to fit in

2. Why is beef better food than cabbage? Because:
A. it tastes better
B. it is more nourishing
C. it is harder to obtain

3. Why do some men who could afford to own a house live in a rented one? Because:
A. they don't have to pay taxes
B. they don't have to buy a rented house
C. they can make more by investing the money the house would cost

4. A dealer bought some mules for \$1,200. He sold them for \$1,500, making \$50 on each mule. How many mules were there?

5. Unscramble the words to form a sentence. Then indicate if the sentence is true or false.
a. happy is man sick always a
b. day it snow does every not

Answers: 1.) B 2.) B 3.) C 4.) 6 5a.) False - A sick man is always happy. 5b.) True - It does not snow every day.

Sources: historymatters.com and official-asvab.com

While the tests helped educators and administrators in the early 20th century understand more about their students and recruits, they had already begun to stray from Binet's original intention. People began to use them as indicators of general aptitude, removing them from the classroom context for which they were intended. Suddenly, an absolute measure existed for a trait that had never been absolute--adding fuel to the fire of the growing eugenics movement. Rather than simply suggesting the one would have success in grade school, higher scores on Binet's test started to mean that one was more fit for breeding. The Advanced Learning Institute reported that between 1907 and 1965, thousands of people were sterilized on the basis of low scores on intelligence tests that characterized them as "feeble-minded."

In 1924, 18-year-old Carrie Buck became the first person subjected to Virginia's Eugenical Sterilization Act. She was classified as "feeble-minded" after a version of the Stanford-Binet test revealed that she had a mental age of nine. Carrie resided in the State Colony for Epileptics and Feeble-Minded in Virginia, the superintendent of which decided that she would be the first person subjected to the new law.

According to Paul Lombardo, a professor at the University of Virginia and an expert on Buck's history, others arranged a trial for Carrie to challenge the new law. Carrie was unable to convince the court of her mental capacity, but her lawyer appealed the court's decision, arguing the new law was discriminatory. The case, Buck v. Bell, went all the way to the Supreme Court, but ultimately, in 1927, the court deemed that there was nothing unconstitutional about Virginia's new law. Carrie, along with around 8,300 other Virginians, was sterilized.

It took the rise of Nazi Germany for people in the United States to recognize the horrific consequences of eugenics. But, chillingly, though the sterilization of individuals in mental institutions came to a halt in the 1970s, the Buck v. Bell decision has never officially been overruled.

Editor's note: NOVA scienceNOW explores the science of intelligence on "How Smart Can We Get," premiering Wednesday, October 24 at 10 pm ET on most PBS stations.