A further refinement of the Binet-Simon scale was published in 1916 by Lewis M. Terman, from Stanford University, who incorporated William Stern's proposal that an individual's intelligence level be measured as an (I.Q.). Terman's test, which he named the Stanford-Binet Intelligence Scale formed the basis for one of the modern intelligence tests still commonly used today. They are all colloquially known as IQ tests.

Binet was born as Alfredo Binetti in Nice, at the time part of the Kingdom of Sardinia. He was the only child of a physician father and an artist mother. His parents separated when he was young, and Binet then moved to Paris with his mother. He attended law school, and earned his degree in 1878. He planned on going to medical school, but decided that his interest in psychology was more important.

Reading books by Charles Darwin, Alexander Bain and others, Binet became a somewhat self-taught psychologist. Introverted and a loner, this self-educating suited him.

In 1894, Binet conducted one of the first psychological studies into chess. It investigated the cognitive facilities of chess masters. Binet hypothesized that chess depends upon the phenomenological qualities of visual memory but after studying the reports by master participants, it was concluded that memory was only part of the chain of cognition involved in the game process. The players were blindfolded and required to play the game from memory. It was found that only masters were able to play successfully without seeing the board for a second time and that amateur or intermediate players found it to be an impossible task. It was further concluded that experience, imagination, and memories of abstract and concrete varieties were required in grand master chess. The line of psychological chess research was followed up in the 1950s by Reuben Fine and in the 1960s by Adriaan de Groot.

Binet attended law school in Paris, and received his degree in 1878. He also studied Natural Sciences at the Sorbonne. His first formal job was as a researcher at a neurological clinic, Salpetriere Hospital, in Paris from 1883–1889. From there, Binet went on to being a researcher and associate director of the Laboratory of Experimental Psychology at the Sorbonne from 1891–1894. In 1894, he was promoted to being the director of the laboratory until 1911 (his death). After receiving his law degree in 1878, Alfred Binet began to study science at the Sorbonne. However, he was not overly interested in his formal schooling, and started educating himself by reading psychology texts at the National Library in Paris. He soon became fascinated with the ideas of John Stuart Mill, who believed that the operations of intelligence could be explained by the laws of associationism. Binet eventually realized the limitations of this theory, but Mill's ideas continued to influence his work.

In 1883, years of unaccompanied study ended when Binet was introduced to Charles Fere, who introduced him to Jean Charcot, the director of a clinic called La Salpetriere. Charcot became his mentor and in turn, Binet accepted a job offer at the clinic. During his seven years there, any and every of Charcot's views were accepted unconditionally by Binet. This of course, was where he could have used the interactions with others and training in critical thinking that a University education provided.

In 1883, Binet began to work in Jean-Martin Charcot's neurological laboratory at the Salpêtrière Hospital in Paris. At the time of Binet's tenure, Charcot was experimenting with hypnotism. Binet was strongly influenced by this great man, and published four articles about his work in this area. Unfortunately, Charcot's conclusions did not hold up under professional scrutiny, and Binet was forced to make an embarrassing public admission that he had been wrong in supporting his teacher.

When his intrigue with hypnosis waned as a result of failure to establish professional acceptance, he turned to the study of development spurred on by the birth of his two daughters, Madeleine and Alice (born in 1885 and 1887, respectively). In the 21 year period following his shift in career interests, Binet "published more than 200 books, articles, and reviews in what now would be called experimental, developmental, educational, social, and differential psychology" (Siegler, 1992). Bergin and Cizek (2001) suggest that this work may have influenced Jean Piaget, who later studied with Binet's collaborator Théodore Simon in 1920. Binet's research with his daughters helped him to further refine his developing conception of intelligence, especially the importance of attention span and suggestibility in intellectual development.

Despite Binet's extensive research interests and wide breadth of publications, today he is most widely known for his contributions to intelligence. Wolf (1973) postulates that this is the result of his not being affiliated with a major university. Because Binet did not have any formalized graduate study in psychology, he did not hold a professorship with a prestigious institution where students and funds would be sure to perpetuate his work (Siegler, 1992). Additionally, his more progressive theories did not provide the practical utility that his intelligence scale would evoke.

Binet and his coworker Fere discovered what they called transfer and they also recognized perceptual and emotional polarization. Binet and Fere thought their findings were a phenomenon and of utmost importance. After investigations by many, the two men were forced to admit that they were wrong about their concepts of transfer and polarization. Basically, their patients had known what was expected, what was supposed to happen, and so they simply assented. Binet had risked everything on his experiment and its results, and this failure took a toll on him.