In 1905, psychologists Alfred Binet and Théodore Simon developed a test in France aimed at identifying children who were struggling in school. This test laid the foundation for what we now know as the IQ test. During the late 19th century, researchers began to explore the idea that cognitive abilities such as verbal reasoning, working memory, and visual-spatial skills were indicative of a general intelligence, often referred to as the g factor. To measure these abilities, Simon and Binet created a series of tests, combining the results into a single score. The test was tailored for different age groups, and a child’s score was compared to the average performance of their peers. The intelligence quotient, or IQ, was calculated by dividing a child’s score by their age and multiplying by 100. Today, an IQ score of 100 is considered average, with 68% of the population scoring within 15 points of this benchmark.
Although Simon and Binet believed their test measured general intelligence, there has never been a universally accepted definition of this concept. This ambiguity allowed for various interpretations of test results. Initially intended to identify children needing extra academic support, IQ tests quickly became tools for categorizing individuals in other ways, often influenced by flawed ideologies. A significant early use of IQ tests was during World War I in the United States, where the military used them to sort recruits and select candidates for officer training. At that time, eugenics—a belief in controlling human traits through selective breeding—was widely accepted. This led to the erroneous belief that intelligence was fixed, inherited, and linked to race.
Under the influence of eugenics, some scientists misused military test results to claim intellectual superiority of certain racial groups. They overlooked the fact that many recruits were immigrants with limited education and English proficiency, leading to a misguided hierarchy of intelligence among ethnic groups. The intersection of eugenics and IQ testing had significant impacts on science and policy. For example, in 1924, Virginia enacted a policy allowing forced sterilization of individuals with low IQ scores, a decision upheld by the United States Supreme Court. In Nazi Germany, the government went as far as sanctioning the murder of children based on low IQ scores.
After the Holocaust and the Civil Rights Movement, the discriminatory applications of IQ tests faced moral and scientific scrutiny. Researchers began to uncover evidence of environmental influences on IQ. For instance, as IQ tests were recalibrated throughout the 20th century, new generations consistently scored higher than previous ones on older tests. This phenomenon, known as the Flynn Effect, occurred too quickly to be attributed to genetics, suggesting that factors like improved education, healthcare, and nutrition played a role.
In the mid-20th century, psychologists also attempted to use IQ tests to diagnose conditions such as schizophrenia and depression. These diagnoses partially relied on clinical judgment and subsets of IQ tests, a practice later found to lack clinical utility. Today, although IQ tests retain many design elements from their early versions, we have developed better methods to identify potential biases. They are no longer used for psychiatric diagnoses, but similar practices using subtest scores are sometimes employed to diagnose learning disabilities, despite expert advice against it.
Psychologists worldwide continue to use IQ tests to identify intellectual disabilities, with results influencing educational support, job training, and assisted living. While IQ test results have been misused to justify harmful policies and unfounded ideologies, the test itself is not without value; it effectively measures reasoning and problem-solving skills. However, this does not equate to measuring an individual’s potential. Many researchers now agree that individuals cannot be accurately categorized by a single numerical score, acknowledging the complex political, historical, scientific, and cultural issues surrounding IQ testing.
Engage in a structured debate with your classmates on the ethical implications of IQ testing. Consider the historical misuse of IQ tests and discuss whether they should still be used today. Prepare arguments for both sides and be ready to defend your position.
Conduct research on the Flynn Effect and its implications on the understanding of intelligence. Prepare a presentation that explains the phenomenon and discusses potential reasons for the observed increases in IQ scores over generations.
Analyze a historical case study where IQ testing was used to support eugenics policies. Discuss the scientific and ethical flaws in the arguments presented at the time and reflect on how these lessons can inform current practices.
Participate in a workshop that explores bias in psychological testing, including IQ tests. Learn about methods to identify and mitigate biases in test design and interpretation, and discuss how these biases can affect outcomes for different demographic groups.
Create a multimedia project that redefines intelligence beyond the scope of traditional IQ tests. Use art, video, or digital media to express diverse aspects of intelligence, such as emotional, social, and creative intelligence, and present your work to the class.
In 1905, psychologists Alfred Binet and Théodore Simon designed a test for children who were struggling in school in France. This test aimed to determine which children required individualized attention and formed the basis of the IQ test. Beginning in the late 19th century, researchers hypothesized that cognitive abilities like verbal reasoning, working memory, and visual-spatial skills reflected an underlying general intelligence, or g factor. Simon and Binet created a battery of tests to measure these abilities and combine the results into a single score. Questions were adjusted for each age group, and a child’s score reflected their performance relative to others their age. Dividing a score by a child’s age and multiplying the result by 100 yielded the intelligence quotient, or IQ. Today, a score of 100 represents the average of a sample population, with 68% of the population scoring within 15 points of 100.
Simon and Binet believed the skills their test assessed would reflect general intelligence. However, there has never been a single agreed-upon definition of general intelligence, which has allowed for varied interpretations of the test results. What began as a method to identify children needing academic assistance quickly evolved into a tool for sorting individuals in other ways, often influenced by flawed ideologies. One of the first large-scale implementations occurred in the United States during World War I, when the military used an IQ test to sort recruits and screen them for officer training. At that time, many people subscribed to eugenics, the belief that desirable and undesirable genetic traits could be controlled in humans through selective breeding. This led to problematic assumptions, including the idea that intelligence was fixed, inherited, and linked to race.
Under the influence of eugenics, some scientists misused military test results to make unfounded claims about the intellectual superiority of certain racial groups. They failed to consider that many recruits were new immigrants who lacked formal education or exposure to the English language, resulting in a misguided intelligence hierarchy among ethnic groups. The intersection of eugenics and IQ testing influenced both science and policy. In 1924, Virginia enacted a policy allowing for the forced sterilization of individuals with low IQ scores—a decision upheld by the United States Supreme Court. In Nazi Germany, the government sanctioned the murder of children based on low IQ scores.
Following the Holocaust and the Civil Rights Movement, the discriminatory uses of IQ tests were challenged on moral and scientific grounds. Researchers began to gather evidence of environmental impacts on IQ. For instance, as IQ tests were recalibrated throughout the 20th century, new generations consistently scored higher than previous ones on older tests. This phenomenon, known as the Flynn Effect, occurred too rapidly to be attributed to inherited traits, suggesting environmental factors such as improved education, healthcare, and nutrition were at play.
In the mid-20th century, psychologists also attempted to use IQ tests to evaluate conditions like schizophrenia and depression. These diagnoses relied partly on the evaluators’ clinical judgment and used a subset of the tests designed for IQ, a practice later found to lack clinical utility. Today, while IQ tests still share many design elements with early tests, we have improved methods for identifying potential biases. They are no longer used for psychiatric diagnoses, but similar practices using subtest scores are sometimes employed to diagnose learning disabilities, despite expert advice against it.
Psychologists worldwide continue to use IQ tests to identify intellectual disabilities, with results influencing educational support, job training, and assisted living. While IQ test results have been misused to justify harmful policies and unfounded ideologies, the test itself is not without merit; it effectively measures reasoning and problem-solving skills. However, this does not equate to measuring an individual’s potential. Many researchers now agree that individuals cannot be accurately categorized by a single numerical score, acknowledging the complex political, historical, scientific, and cultural issues surrounding IQ testing.
Psychologists – Professionals who study mental processes and behavior, often conducting research or providing therapy to understand and improve mental health. – Many psychologists have contributed to the development of cognitive-behavioral therapy, which is widely used to treat anxiety and depression.
Intelligence – The ability to acquire and apply knowledge and skills, often measured through various cognitive tests. – The study of intelligence has evolved significantly since the early 20th century, with researchers exploring both genetic and environmental influences.
Eugenics – A controversial movement that aimed to improve the genetic quality of the human population through selective breeding and sterilization, often associated with unethical practices. – The history of eugenics serves as a cautionary tale about the misuse of scientific research to justify discrimination and inequality.
Discrimination – The unjust or prejudicial treatment of different categories of people, often based on race, age, or gender, which can have significant psychological impacts. – Studies in social psychology have shown how discrimination can lead to increased stress and mental health issues among marginalized groups.
History – The study of past events, particularly in human affairs, which can provide insights into current psychological and social phenomena. – Understanding the history of psychological theories helps students appreciate the evolution of ideas and the context in which they developed.
Testing – The process of administering psychological assessments to measure various mental functions and behaviors, often used in educational and clinical settings. – Psychological testing can help identify learning disabilities in students, allowing for tailored educational interventions.
Education – The process of facilitating learning, or the acquisition of knowledge, skills, values, and habits, which can significantly influence cognitive development. – Research in educational psychology examines how different teaching methods impact student motivation and learning outcomes.
Abilities – Inherent or acquired skills and competencies that enable individuals to perform tasks or solve problems effectively. – Cognitive abilities such as memory and reasoning are often assessed in psychological studies to understand human intelligence.
Research – The systematic investigation into and study of materials and sources to establish facts and reach new conclusions, often forming the basis of psychological theories. – Recent research in developmental psychology has provided new insights into how early childhood experiences shape personality.
Biases – Systematic deviations from rationality in judgment, often resulting from cognitive shortcuts or social influences, which can affect decision-making and perception. – Awareness of cognitive biases is crucial for psychologists to ensure objectivity in their research and clinical practice.
