Classics in the History of Psychology

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Introduction to:

"New Methods for the Diagnosis of the Intellectual Level of Subnormals."
Alfred Binet & Theodore Simon (1905).

Sir Francis Galton, who pioneered the study of individual differences in the late nineteenth century, was the first to attempt to measure intelligence. Following in the tradition of British empiricism, Galton believed that intelligence was a function of sensory acuity. Thus, individuals who exhibited high degrees of sensory discrimination were assumed to be highly intelligent. Moreover, because sensory acuity reflected native endowment, individual differences in intelligence were assumed to be primarily a function of heredity. In support of his hereditarian views, Galton had argued in his 1869 book, Hereditary Genius, that high levels of intellectual achievement followed genealogical lines; that is, eminent fathers tended to have eminent sons. In 1888, Galton set up an "anthropometric laboratory" in which he used such measures of sensory discrimination as visual acuity, auditory accuracy, and breathing capacity to assess levels of intelligence. Galton's efforts were followed up in the United States by psychologist James McKeen Cattell. Cattell coined the term, "mental tests" to refer to Galtonian measures. By 1901, however, after a series of studies by Cattell and his students that showed no relationship between sensory discrimination and indices of intellectual performance (academic grades), the Galtonian approach to measuring intelligence was generally abandoned. It appeared as though the "mental testing movement" was at an end.

It was against this backdrop of Galtonian measurement that Alfred Binet began his work on intelligence scales. Binet was a leading French psychologist with diverse interests in hypnosis, thinking, and individual differences. In contrast with Galton's use of sensory discrimination, Binet had argued in the 1890s that individual differences in intelligence had to be detected through measures of such complex processes as memory, imagination, attention, comprehension, and suggestibility. In 1904, Binet was appointed by the French minister of public instruction to a commission concerned with the problem of retardation among public schoolchildren in Paris. The early twentieth century was a period of time, both in Western Europe and North America, when public education was rapidly expanding in urban centers, a reflection of the increasing effects of urbanization and industrialization. School administrators turned to social scientists for expertise in reorganizing schools for more efficient classroom management. Such issues as how to handle slow learners was thus of paramount importance to educators.

It was clear to the commission that in order to address the problems of retarded children, special education programs had to be developed. It was therefore necessary to devise a means of identifying retarded children. Binet thus set about developing a scale that could differentiate those children who were slow learners from those who were able to keep pace with the level of instruction (normal children). He collaborated with Théodore Simon, a young physician who had worked with retarded children. Binet and Simon proceeded to assemble a scale composed of measures of the kinds of higher mental processes that Binet had argued were central to the assessment of intelligence. They constructed some of the specific cognitive tests themselves but they also modified a number of tests that had been developed by two French physicians, Drs. Blin and Damaye. Binet and Simon drew samples of "normal" children and children thought to be retarded from schools, hospitals, orphanages, and asylums. The children ranged in age from two to twelve. They used these samples to try out the various tests with the goal of selecting those tests that clearly discriminated between the two groups of children. By this means, they selected thirty tests arranged roughly in ascending order of difficulty.

In this 1905 paper, Binet and Simon spell out the rationale for their scale and provide guidelines for its administration. The scale, in its entirety (thirty tests) is included. Thus, this paper served as the source for disseminating information about the first Binet-Simon scale, as well as the source for the practical use of the scale. In the introduction, the authors state that the scale is intended to study the child's condition at the time of administration. The goal is to determine the child's present mental state so that a decision can be made about the appropriate curriculum placement; that is, special education or regular classroom instruction. The authors caution that in cases of retardation, it is irrelevant to consider etiology; that is, whether the retardation is acquired or congenital. In pioneering a new assessment method, the authors also make a point of distinguishing the target group the scale is aimed at. As they indicate, the scale is only appropriate for assessing the mental performance of children. It is thus not concerned with identifying the psychologically unstable, insane, or organically deteriorated; only in comparing inferior and normal intelligence.

In justifying the value of their method, Binet and Simon note that its objective grounding in normative data, it avoids the subjective bias inherent in the traditional practice of basing diagnoses of retardation on medical observation. The psychological method measures the state of general intelligence at the present moment. The child's mental capability is assessed through exercises of comprehension, judgment, reasoning, and invention. These tests reflect the nature of intelligence, which is based on the practical ability to adapt to one's circumstances. The scale thus does not assess special abilities or acquired information (achievement). Rounding out the introductory section, Binet and Simon provide guidelines for administration, underscoring the training necessary for being able to establish rapport and achieve unbiased test administration.

The major part of the paper is concerned with presenting the thirty tests, starting with the least difficult. For each test, the procedure of administration is spelled out and guidelines are provided with respect to the normative performance expected. The first six tests assess the earliest signs of attention and memory. These include the coordination of the head to follow a lighted match, hand coordination to tactile and visual stimuli, unwrapping food covered by paper, and the imitation of gestures and following simple commands. Normal two-year old children could pass all of these tests but severely retarded children (the category of idiocy) could pass only a few or none. Tests seven, eight, and nine assess communication skills beyond the two-year level. These tests distinguished between severe retardation (idiocy) and moderate retardation (imbecility). In tests ten and twelve , children are asked to compare lines and weights. Failure reflects the inability to understand what is required. In repeating three digits (test eleven) it is important to note the kind of error. Slight errors may simply indicate distraction, while totally wrong answers indicate a lapse of judgment that suggests retardation. Suggestibility (test thirteen) can also point to signs of retardation if the child responds without resistance to absurd requests by the examiner, such as asking for a button when such an object is not present. Definitions and repetition of sentences (tests fourteen and fifteen) differentiate between younger and older children.

As Binet and Simon reported in a later publication, test sixteen (differences between words, e.g. paper and cardboard) discriminated between moderately and slightly retarded children. Tests seventeen through twenty-six measure various cognitive abilities, including memory, similarities, and language usage. These tests discriminated between younger and older normal children. Test twenty-seven, assessing comprehension (responses to abstract questions like "When a person has offended you, and comes to offer his apologies, what should you do?"), was especially useful for differentiating between the slightly retarded and the normal. As Binet and Simon state, "any mind which is not apt in abstraction succumbs here." Tests twenty-eight and twenty-nine assess attention, reasoning, and visual ability. Test thirty, the final and most difficult, measures abstraction as reflected in accounting for the difference between abstract words, such as boredom and weariness.

The major intent of the 1905 scale was to differentiate the slightly retarded (Henry H. Goddard's category of "moron") from the normal school population. Children who were classified as slightly retarded could then be targeted for special education. In a 1907 book written for the general public, Binet provided guidelines on the admission of retarded children to special education classes and underscored the need for assessment. In 1908, Binet and Simon revised their scale, arranging the tests by age levels. This reorganization was based on the age norms that they had established with the 1905 scale, which had been administered to a large sample of normal children between the ages of three and thirteen. A criterion of 75% passing was used to determine each test's placement. Thus, if 75% or more of six-year-olds passed a given test, it was placed at the six-year level. An especially useful aspect of the 1908 scale was that it provided for the possibility of expressing a child's level of intelligence in relation to the age group whose performance he or she matched. A six-year old child, for example, who performed as well as the average eight-year old would have a "mental level" of eight. The mental level represented the averaging out of successes and failures that matched the given age norm. When Binet's writings were translated by the American mental testers, the term "mental age" was used and implied an ordered developmental progression that Binet had not intended. The Binet-Simon scale was revised again in 1911, the year of Binet's death, and included normative data on an adult sample (fifteen-year olds).