So far, you've learned about some of the major cognitive abilities studied by psychologists including problem solving, decision-making, and language. All of these abilities can be considered part of what psychologists commonly refer to as intelligence, a subject that has served as a major point of interest and controversy in psychology. While few psychologists agree on a single definition of intelligence, for its purposes this book will refer to it as the ability to mentally comprehend information, which involves the capacity to reason, think abstractly, plan, learn, utilize language, and solve problems.
The earliest attempts to measure intelligence began early in the twentieth century when the French government asked psychologist Alfred Binet (1857–1911) to devise a method to identify children who might need specialized assistance in school. Binet devised a series of questions focused on things such as problem solving, memory, and attention. After observing that some children answered questions that were typically known by children of either a lower or higher age group, Binet introduced a concept referred to as mental age, a measurement of intelligence that is based on the average abilities of a given age group.
Does a high IQ predict success in life?
In one longitudinal study of 1,500 California children, researchers found that having a high IQ as a child was no guarantee for later life success. Other factors such as motivation, social support, and hard work also play a major role in life success.
The intelligence scale that Binet developed became the basis for the modern intelligence tests that are still being used today. One widely used assessment tool is the Stanford-Binet, which presents a measurement of intelligence in a single number known as an intelligence quotient (IQ). The average intelligence score is 100, and two-thirds of all IQ scores range between 85 and 115.