We have a tendency to believe that having a high IQ is a sure-fire way to guarantee success in life. After all, some of the most successful people in different fields such as science, art, business, and entertainment are extremely bright.
While today we often assume that those with extremely high IQs are naturally more successful, there also exists a competing stereotype that people with very high IQs are sometimes less likely to prosper in multiple life domains; that these highly intelligent individuals have poor social skills and that they might struggle with mental instability. Consider the brilliant but eccentric and socially awkward characters that abound in popular culture, from the brainy but persnickety Sheldon Cooper on television's The Big Bang Theory to the clever yet idiosyncratic Sherlock Holmes of Arthur Conan Doyle's classic detective series.
You probably know a few extremely smart people who are also very successful, but you can also likely think of several people who are equally smart yet not as prosperous. If people have similar levels of intelligence, what leads to this disparity in outcomes?
Does having a high IQ predict greater success in life?
Psychologists have long been interested in understanding how a person's IQ influences their ability to function in multiple life domains. The very first IQ tests were developed as a means of identifying school children who needed extra academic help, but the tests quickly became a popular way of identifying individuals who had above average scores as well.
First let's start by answering a basic question: What exactly do we mean by "high IQ?" On standardized tests of intelligence, such as the Stanford-Binet test, the average IQ score is 100 and anything over 140 is considered a high, or genius-level IQ.
One of the best-known studies on intelligence tackled the question of whether high IQ might be linked to life success.
Terman's Study of Gifted Children
Starting in the early 1920s, psychologist Lewis Terman began to investigate the idea that genius-level IQ was associated with social and personal maladjustment. He selected approximately 1500 children from California between the ages of 8 and 12 who had an IQ of at least 140, the minimum required to be considered a genius. The average IQ score of the group of participants was 150, and 80 of these children had scores above 170.
Over the next few years, Terman continued to track these children to see how high intelligence might impact the course of their lives. What Terman discovered was that these kids tended to be both socially and physically well-adjusted. These high IQ kids were not only academically successful; they also tended to be healthier, taller, stronger, and less accident-prone than same-aged kids with lower IQs.
After Terman's death in 1956, several other psychologists carried on the original research and followed the original subjects. Known as the Terman Study of the Gifted, the study continues to this day and is the longest-running longitudinal study in the history.
Psychologists continue to track the surviving original participants, some of whom have gone on to achieve great success in life. Some of these individuals include famed educational psychologist Lee Chronbach, I Love Lucy writer Jess Oppenheimer, child psychologist Robert Sears, scientist Ancel Keys, and many others who became faculty members at colleges and universities.
As of the year 2003, there were 200 original participants still living. The study is expected to continue until the last member of the group dies or withdraws.
So how did the majority of Terman's subjects fare in life?
- When they were assessed in 1955 when the average yearly income was $5,000, the average income level for Terman's subjects was an impressive $33,000.
- Two-thirds had earned college degrees and a large number of the participants had gone on to earn graduate and professional degrees.
- Many members of the group became doctors, lawyers, business executives, professors, and scientists.
But not all of these high IQ subjects were so successful. Researcher Melita Oden, who had carried on the research after Terman's death, decided to compare the 100 most successful individuals (group "A") to the 100 least successful (group "C"). While they essentially had the exact same IQs, only a few people from group C had become professionals, most earned just slightly above the average yearly income, and they had higher rates of alcoholism and divorce than individuals from group A.
What could explain this disparity? If IQ predicts success, why did these individuals with similar intelligence scores fare so differently in life?
Terman had noted that as children the individuals in group A tended to exhibit "prudence and forethought, will power, perseverance, and the desire to excel." Later as adults, those from group A tended to rate higher than those from group C on three key traits: goal-orientation, self-confidence, and perseverance.
This suggests that while IQ can play a role in life success, personality traits are also important factors in determining outcomes.
Potential Problems With Terman's Study
Critics have suggested that Terman's study suffers from several notable weaknesses. First, the study lacked a generalizable sample. The original subjects were chosen for the study because they were nominated by their teachers before their IQ was actually tested. It is highly likely that teachers selected children who were both smart and well-adjusted over kids who may have been just as intelligent but less socially competent.
Because Terman's study was longitudinal, the results might be influenced by cohort effects since the original group of participants may have shared characteristics and experiences tied to the specific era in which they lived. For example, the Great Depression and World War II may have prevented many members of the group from attending or completing college. Many women from the group may not have attended school because, at the time, it was more common for women to be homemakers rather than career professionals.
Other researchers have suggested that any randomly selected group of children with similar backgrounds would have been just as successful as Terman's original subjects.
Modern Research on IQ and Life Success
One thing that IQ scores have been shown to reliably predict is academic success in school. However, it is important to note that doing well in school doesn't necessarily mean that a person will be successful at work or in other life areas.
"The best thing IQ measures is the ability to do well in school," suggested Alan Kazdin, professor of psychology and director of the Parenting Center and Child Conduct Clinic at Yale University, to ABC News. "At this age, consider it potential. But you have to have the right environment to nurture this."
Other research has indicated that children with exceptional academic abilities may actually experience more social problems, including social isolation, than less-gifted students. Another study found that people with higher IQs were more likely to smoke marijuana and use other illegal drugs. Why? Researchers suggest that those with high IQs also tend to score higher on a personality trait known as openness to experience. Since they are more willing to try new things, high IQ individuals may be more likely to seek out novel experiences.
While researchers continue to debate the extent that IQ influences life success, most contemporary research seems to support Terman's overall findings. Intelligence is an important component, but high IQ alone is no guarantee of success in work or other areas of life.
So what's the bottom line?
The results of Terman's longitudinal study of gifted children suggest that IQ can play an important role in determining life success; but high IQ alone is not enough. Variables such as family background, socioeconomic status, and educational experiences as well as personality factors including motivation, willingness to work hard, being committed to goals, creativity, and emotional maturity are also strongly linked to success in life.
Goleman, D. (1980, February). 1,538 little geniuses and how they grew. Psychology Today, 28-53.
Holahan, C. K., & Sears, R. R. (1995). The Gifted Group in Later Maturity. Stanford University Press: Stanford, CA.
Leslie, M. (2000). The vexing legacy of Lewis Terman. Stanford Magazine.
Szalavitz, M. (2011, Nov. 15). Why kids with high IQs are more likely to take drugs. Time. Retrieved from http://healthland.time.com/2011/11/15/why-kids-with-high-iq-are-more-likely-to-take-drugs/
Terman, L. M. (1925). Mental and Physical Traits of a Thousand Gifted Children. Genetic Studies of Genius Volume 1. Stanford (CA): Stanford University Press.
Terman. L. M., & Oden, M. H. (1959.) Genetic studies of genius. Vol. V. The gifted at mid-life: Thirty-five years' follow-up of the superior child. Stanford, CA: Stanford University Press.
Winner, E. (1997). Exceptionally high intelligence and schooling. American Psychologist, 29, 1070-1081.