Item from Alfred Binet and Théodore Simon’s scale for measuring intelligence in children, who have to say, for each pair of faces, which one is the prettier.
Individual Differences and Development
Item from Alfred Binet and Théodore Simon’s scale for measuring intelligence in children, who have to say, for each pair of faces, which one is the prettier.
Alfred Binet and Théodore Simon developed the first intelligence tests for children. Influenced by their work, Jean Piaget proposed that mentally we develop in stages. In the first stage, children come to know that objects in the world can be lost and found. In the next stage, children are influenced by surface appearances. Only in adolescence is a stage reached in which people start to think logically. Testing traveled to America, where multiple-choice tests were used to measure people’s intelligence. What should we do for people who score less than average on such tests? The evolutionary process of variation gives us different intellectual abilities by mere luck. Might justice suggest that those who are fortunate contribute to those who are less fortunate?
The Testing of Intelligence
A turning point in psychology occurred with the testing of children’s intelligence. At the beginning of the twentieth century, a law was passed in France that all children between the ages of six and fourteen should receive school education. The question arose as to whether it might be better for children who had difficulties with learning to be educated in special classrooms. But how might such children be identified? Partly in response to this, in 1908, Alfred Binet and Théodore Simon published a test with thirty items to measure children’s intelligence.1
The test was administered by a trained person. The first item was easy: could children follow a beam of light with their eyes? A slightly harder task was to name body parts. More difficult tasks included naming differences between pairs of things, for instance, for the three pairs of cartoon faces shown at the chapter opening, the tester asked the children which of each pair was the prettier. Then the tester asked the children to construct sentences from three words, to repeat a list of seven random digits, and to make change from some money.
Binet and Simon asked teachers to select children who were average for their age. These children took the test and their results set standards for it. If a new child was then tested and could do all the tasks that average seven-year-olds could do, but not those that only older children could do, the child was given the mental age of seven.
The term “IQ” stands for “Intelligence Quotient.”2 It’s the ratio of each child’s measured mental age to actual age, multiplied so that the normal person has an IQ of 100. So, if Aimée can do the tasks that average nine-year-olds can do, she has a mental age of nine. If she is actually aged seven, her IQ will be 9 divided by 7 multiplied by 100 = 128. Nowadays IQ is assessed in relation to normal populations rather than in terms of mental ages. One hundred is the average; 95 percent of people have IQs between 70 and 130.
Alfred Binet was born in Nice, in 1857.3 He took a law degree in 1878, then considered going into medicine, but he became interested in psychology, which was not much developed, so he taught it to himself. In 1894, he became director of the Laboratory of Experimental Psychology at the Sorbonne, in Paris. In 1903, he published Experimental Studies of Intelligence. Soon after this he was joined by a young physician, Théodore Simon, who was fascinated by his findings.
Work on testing opened up a range of issues in psychology: how people may see the world differently; how damage to our brains might be diagnosed by testing; how, amid the variation that Darwin observed, might we live in a world of people who are different?
Binet and Simon offered one kind of answer. It was that children who scored lower on their tests needed extra help in school so that they, like everyone else, could have a chance to reach their potential. To understand how education might be appropriate for children of different ages, and of different abilities, a theory was needed of how children develop.
Stages of Development
The most influential theory of cognitive development is that of Jean Piaget.4 Born in 1896, Piaget grew up in Neufchatel, in Switzerland.5 He went to school there, and he received his PhD in biology from the University of Neufchatel. After that he spent some time studying in Paris. There he taught at a school run by Alfred Binet, and studied with Binet’s collaborator, Théodore Simon. In 1921 he returned to Geneva, Switzerland, where most of his career was centered. Earlier in life Piaget had been interested in psychoanalysis but, deciding that Freud’s work was mainly about emotional development, he thought he would concentrate on cognitive development. In 1923, he married Valentine Chatenay. The couple had three children, Jacqueline, Lucienne, and Laurent, who became the main participants in his studies. The Piaget family is pictured in figure 8.
Jean Piaget proposed that children pass through stages, each based on a distinctive kind of understanding: an implicit theory of the world and how it works.
First, from birth to age two, is the sensory-motor stage in which children come to recognize the outside world. At this time, the children’s implicit theory is that when they act on the world it changes, and that if an object disappears, it still exists somewhere, so they can search for it. Piaget called this object permanence. Next, from age two to age six, came what Piaget called the pre-operational stage. Children come to represent the world symbolically through language and mental images, but their understandings depend on surface appearances. In the third stage, from age six to age twelve, which Piaget called the stage of concrete operations, children are able to carry out mental operations—thoughts—that enable them to combine and transform objects and actions. In the fourth stage, from ages twelve to nineteen, which Piaget called the stage of formal operations, adolescents become able to think logically and to take an interest in abstractions.
Piaget and his colleagues worked to diagnose what stage children were in by giving them carefully arranged questions. The questions were influenced by those devised by Binet and Simon but, rather than having their purpose be to diagnose differences, they were intended to give insights into how children think. Thus, a four-year-old child might be shown a row of coins, and alongside it the same number of coins spread out so that the row is longer. When asked which row has more coins in it, four-year-olds tend to answer that it’s the longer one. In their implicit theory longer means more. At this stage they don’t know that a better theory would involve counting the coins.
Figure 8. Jean and Valentine Piaget in 1936, with their children who were the main subjects in Jean Piaget’s research on cognitive development. Source: © Archives Jean Piaget, Geneva.
One well-known test invented by Piaget, to distinguish the pre-operational stage from the stage of concrete operations, was to judge the amount of water in glasses of different shapes. Children before about the age of six think there is more water in a tall, thin glass than in a short, fat glass. And they think there is more in the tall glass even if the water is poured into it from the short, fat glass. They don’t at that stage think: “Well none was spilled so it must be the same amount.” Whereas some people in education ask what kind of teaching would enable children to move more quickly to the next stage, Piaget thought that enabling children to explore implications of their current theory-stage would be better for their development. Some of Piaget’s tests, like the one with glasses of water, have become famous. Tasks of the kind Piaget developed have also influenced the measurement of intelligence.
Adult Testing and Eugenics
Mental testing was started not by Binet and Simon, but by Francis Galton, a half-cousin of Charles Darwin. In 1884, Galton established what he called an anthropometric laboratory at London’s International Health Exhibition. People paid three pence to be tested and were given a copy of their measurements. Data were collected from more than 9,000 people, on each of whom seventeen measurements were made of keenness of sight, color sense, hearing, touch, breathing capacity, strength of pull and of squeeze, height when standing and sitting, body weight.
Galton took his research in a direction based on Darwin’s idea of variation, but his new direction was one of which Darwin would probably have disapproved. Galton was keen to make the human race better, and his idea was to use selective breeding to increase the proportion of certain variations (superior people) and decrease the proportion of others (the inferior). For this, in 1904, Galton described a concept he had invented: eugenics.
When Binet and Simon’s test reached America it was translated into English and became the Stanford-Binet test. Many of those who developed this test worked to use intelligence testing to promote eugenics. In the New World, rather than having testers work with individual children, new formats were devised.6 One kind, the multiple-choice questionnaire, has become familiar. Questionnaires of this kind can easily be administered to large numbers of people, including adults. In this way, as Leo Kamin discusses in The Science and Politics of IQ, when the United States joined World War I, some two million recruits to the army were administered a multiple-choice questionnaire called the Army Alpha Test, and given grades from A to E. Grade A denoted an officer type. B denoted a non-commissioned officer, and C a private. D denoted fair soldiers who were often slow in learning. Those at a half grade lower, D-minus, were designated as barely fit for military service, and E were said to be unqualified for military service. Although the tests came too late to have any substantial effect on army policy at that time, subsequent analyses of the results shocked the testers.
Results of the Army Alpha Test of recruits who had been born in America and immigrants from Northern Europe (designated Nordic races) had the highest average scores, whereas the majority of those who had immigrated from Russia, Poland, and Italy had scored D or below. An implication seemed critical for eugenic policies. The recommendation was that immigration from Southern and Eastern Europe should be curtailed. These sentiments were different from those expressed by Emma Lazarus in the poem that in 1903 (just twenty years earlier) had been engraved on the pedestal of the Statue of Liberty.
Give me your tired, your poor,
Your huddled masses yearning to breathe free,
The wretched refuse of your teeming shore.
Send these, the homeless, tempest-tost to me,
I lift my lamp beside the golden door!
Kamin describes how one theorist, Harry Laughlin, categorized D-minus people as follows: “Cost of supervision greater than the value of labor,”7 and of how, in 1923, Arthur Sweeney wrote part of an appendix for the U.S. House of Congress Committee on Immigration which included the following:
The D minus group can not go beyond the second grade … we shall degenerate to the level of the Slav and Latin races … pauperism, crime, sex offences and dependency … guided by a mind scarcely superior to the ox … we must protect ourselves against the degenerate horde.8
In 1924, the U.S. Congress passed a law to limit further immigration from countries of southern and eastern Europe. As Kamin puts it: “The law, for which the science of mental testing may claim substantial credit, resulted in the deaths of literally hundreds of thousands of victims of Nazi biological theorists.”9
Intelligence and Inheritance
The early American intelligence testers failed to consider how long immigrant recruits who had taken the Army’s Alpha Test had lived in the United States. Had they done so they would have seen that men’s scores on this test were closely related to how long they had lived in a country where the language was English—the language in which the tests were written. It was the language spoken by immigrants from Britain and Ireland, but not by most of those from Poland and Italy. Had the testers thought a bit harder, moreover, they might also have realized that something other than inheritance was involved in answering questions of the Army Alpha Test, such as the one in which it was asked whether the Overland car was manufactured in Toledo, Buffalo, Detroit, or Flint. (Toledo is correct.)
Many early testers were not trying to answer questions in a scientific way but were looking for confirmation of what they already knew. When standardizations began of the Stanford-Binet test, the issue of sex differences arose. Lewis Terman and Maud Merrill put it like this: “A few tests in the trial batteries which yielded the largest sex differences were eliminated early on as probably unfair. A considerable number of those retained show statistically significant differences in the percentages of success for boys and girls.”10
The testers had found that when IQs of girls were measured, on average they were higher than those of boys. In the male-dominated society of that time, the testers thought this could not be true. The solution was that they altered some of the questions so that, on average, girls and boys scored the same. When, later, black children were tested, their average IQ scores were found to be lower than those of white children. This result was considered to be true. In the 1986 revision of the Stanford-Binet test, it is described how items have been reformulated to minimize differences of both gender and race.
In 1994, the psychologist Richard Herrnstein and the political scientist Charles Murray published The Bell Curve, in which they argued that IQ is associated with a range of personal factors such as income, job performance, and crime.11 They don’t claim that it is all a matter of genetics, but they do discuss the issue in terms of race, and this caused an outcry. In his review of the book in the New Yorker, Stephen Gould states, “The authors omit facts, misuse statistical methods, and seem unwilling to admit the consequence of their own words.” The controversy continues.
In many modern studies of intelligence, scores are compared in pairs of identical (monozygotic) twins and in pairs of non-identical (dizygotic) twins. As Robert Plomin and Frank Spinath show, by adulthood, correlations between IQ scores of the monozygotic twins (who share 100 percent of their genes) are about 0.8, while correlations between scores of dizygotic twins (who share 50 percent of their genes) are about 0.4. This means there is a substantial inherited factor in IQ. Modern research makes it clear that single genes have only tiny effects on psychological functions such as ability to learn and succeed.12 Such effects are due to large groups of genes, working together.
Twin studies show that IQ is an example of Darwin’s idea that psychological characteristics, not just physical ones, can be inherited. It is an easily administered predictor of how well a person is likely to perform in school, at college or university, and in employment. It even helps predict, to some extent, how people are likely to manage against those slings and arrows of fortune that can threaten to precipitate emotional disorders. As a predictor, it is by no means exact. Individual lives, with their many opportunities taken and declined, are more telling than a simple number of the kind IQ provides.
We now recognize that it is unacceptable in society to have members of one group able to exercise power to curtail the life-chances of another group to which they do not belong. To be born with these parents rather than those, with one set of abilities rather than some other set, are matters of chance. They are arbitrary and potentially unfair.
In this book we discuss some answers that cognitive science has offered us. Perhaps even more important are questions. Here is one: how are different individual abilities and fairness to be related in society?
In 1972, John Rawls argued that what we mean by justice includes reducing sources of unfairness. He proposed the idea that he calls the “original position.” In it we imagine that, before our birth, we take part in discussions in groups of others, about what kind of society we would like to be born into. These meetings take place before we know whether we will be female or male, whether we will be born into a family that is rich or poor, what ethnic group we will be in, whether we will be more or less intelligent. Rawls proposes that among the results of such discussions is a likely choice of a kind of society in which, if by chance we happen to have certain abilities, we should be able to develop them but, at the same time, from resources we would gather as a result of better life-chances and abilities, we would also contribute to the well-being of people whose life-chances have been less. Of course, not all societies aspire to fairness, but we can ask how societies that do aspire in this way can promote policies that embody this principle.
