What is IQ?
IQ is a battery of tests measuring basic academic skills and scored according to a pre-set curve.
What do IQ tests measure?
IQ tests measure current academic abilities -- not any sort of fixed, innate intelligence. More specifically, the best-known IQ battery, "Stanford-Binet 5," measures Fluid Reasoning, Knowledge, Quantitative Reasoning, Visual-Spatial Processing, and Working Memory -- skills known collectively as "symbolic logic." IQ tests do not measure creativity;[i] they do not measure "practical intelligence" (otherwise known as "street smarts");[ii] and they do not measure what some psychologists call "emotional intelligence."
Harvard's Howard Gardner:
"The tasks featured in the IQ test are decidedly microscopic, are often unrelated to one another, and . . . are remote, in many cases, from everyday life. They rely heavily upon language and upon a person's skill in defining words, in knowing facts about the world, in finding connections (and differences) among verbal concepts . . . . Moreover, the intelligence test reveals little about an indivdual's potential for further growth."[iii]
Tufts' Robert Sternberg:
IQ problems tend to be "clearly defined, come with all the information needed to solve them, have only a single right answer, which can be reached by only a single method, [and are] disembodied from ordinary experience . . . . Practical problems, in contrast, tend to require problem recognition and formulation . . . require information seeking, have various acceptable solutions, be embedded in and require prior everyday experience, and require motivation and personal involvement."[iv]
How are IQ scores determined?
Raw individual test scores are converted so that they correlate perfectly to a bell curve representing the entire population of same-age students. The average score is always 100.
- An IQ score of 100 means that 50% of the people in your age group scored better, and 50% scored worse.
- An IQ score of 85 means that 84.13% of the people in your age group scored better, and 15.87% scored worse.
- An IQ score of 130 means that 2.28% of the people in your age group scored better, and 97.72% scored worse.
Can your IQ score change over time?
Absolutely. "IQ scores," explains Cornell University's Stephen Ceci, "can change quite dramatically as a result of changes in family environment (Clarke, 1976; Svendsen, 1982), work environment (Kohn and Schooler, 1978), historical environment (Flynn, 1987), styles of parenting (Baumrind, 1967; Dornbusch, 1987), and, most especially, shifts in level of schooling."[v]
If IQ scores can change over time, why do most people's IQ scores stay reasonable stable?
What any individual can achieve with the right combination of assets and gumption is entirely different from what most people actually do achieve. Most people settle into a particular academic standing early in life and do not substantially deviate from that standing. That's the inertia of life and human circumstance; the students performing at the top of the class in 4th grade tend to be the same students performing at the top of the class in 12th grade.[vi] That's because the factors that enabled them to do well in fourth grade usually stay in place throughout their school lives: same parents, same community, same economic and cultural resources, etc.
Being branded with a low IQ at a young age, in other words, is like being born poor. Due to personal circumstances and the mechanisms of society, most people born poor will remain poor throughout their lives. But that sure doesn't mean anyone is innately poor or destined to be poor; there is always potential for any poor person to become rich.
So IQ scores don't imply any sort of fixed or innate intelligence?
Quite the contrary. We know that the abilities IQ measures are skills, and we know that people can learn these skills. "Intelligence," Robert Sternberg has declared, "represents a set of competencies in development." There is plenty of evidence, for example, that schooling raises overall academic intelligence.[vii] There is also evidence that most human beings are not reaching their cognitive or academic potential.[viii] Better schools and higher standards can raise the level of learning for nearly all students.
Don't genes set and limit our intelligence? Isn't intelligence "heritable?"
Genes do have a substantial impact on many aspects of our physiology, including intelligence. But, sadly, very sloppy science and journalism have led us to believe that intelligence is essentially innate. It isn’t. Rather, intelligence is fluid, and is a function of many dynamic components. So while genes play a role in limiting our potential, every indication is that most of us don't come close to even grazing such limits, meaning that – from a practical perspective – gene-based limits do not hold us back.
Who invented IQ and why have we all been taught that it reveals our innate intelligence?
It's a long story (which I expand on in my book), but the short answer is that the modern IQ test was invented by Stanford psychologist Lewis Terman, a prominent eugenicist, early in the 20th century. Terman himself was absolutely convinced that IQ scores revealed innate intelligence. "Psychological methods of measuring intelligence [have] furnished conclusive proof that native differences in endowment are a universal phenomenon," he wrote in 1925. But the whole concept of innate intelligence turns out to be a faulty one.
Terman also bizarrely assigned a protégé, Catherine Cox, to determine the IQs of long-dead geniuses -- a laughable farce considering how IQ is normally measured and what it is conventionally said to reveal. They assigned a score of 200 to Terman's hero Francis Galton -- the father of innate intelligence.[ix]
- David Shenk
[i] IQ scores do not identify the most successful and creative artists or scientists:
- Taylor, I. A., "A retrospective view of creativity investigation.’ In Perspectives in creativity, I. A. Taylor and J. W. Getzels, eds., Aldine Publishing Co, pp. 1-36. 1975.
IQ does not distinguish the best chess players from others:
- Doll, J., and U. Mayr, 1987, ‘Intelligenz und Schachleistung - eine Untersuchung an Schachexperten. [Intelligence and achievement in chess - a study of chess masters].’ Psychologische Beiträge, 29: 270-289.
[ii] IQ scores have a weak correlation with nonacademic intelligence and with performance in everyday tasks in other cultures:
- Joan Miller, "A Cultural-Psychology Perspective On Intelligence," in Intelligence, heredity, and environment, Robert J. Sternberg, Elena Grigorenko Cambridge University Press, 1997. p. 292.
[iii] Howard Gardner, Frames of Mind, p. 18.
[v] Ceci's citations:
- Ann M. Clarke, Alan D. Clarke, Early Experience and the Life Path, Somerset, 1976.
- Dagmund Svendsen, Factors Related To Changes In IQ: A Follow-Up Study Of Former Slow Learners, Journal of Child Psychology and Psychiatry, Volume 24 Issue 3, Pages 405 - 413, 1982.
- Melvin Kohn and Carmi Schooler, "The Reciprocal Effects of the Substantive Complexity of Work and Intellectual Flexibility: A Longitudinal Assessment" (with Carmi Schooler). 1978. American Journal of Sociology 84 (July): 24-52.
- Flynn, J. R. (1987). Massive IQ gains in 14 nations: What IQ tests really measure. Psychological Bulletin, 101,171-191.
Styles of parenting
- D. Baumrind, "Child care practices anteceding three patterns of preschool behavior," Genetic Psychology Monographs, 75, 43-88, 1967.
- Sanford M. Dornbusch, Philip L. Ritter, P. Herbert Leiderman, Donald F. Roberts and Michael J. Fraleigh, " The Relation of Parenting Style to Adolescent School Performance," Child Development, Vol. 58, No. 5, Special Issue on Schools and Development (Oct., 1987), pp. 1244-1257.
Individuals' IQ scores can change significantly over time:
[vi] From the 1995 APA report: "It is important to understand [that] a child whose IQ score remains the same from age 6 to age 18 does not exhibit the same performance throughout that period. On the contrary, steady gains in general knowledge vocabulary, reasoning ability, etc. will be apparent. What does not change is his or her score in comparison to that of other individuals of the same age."
[vii] - Ceci, Stephen J., On Intelligence-- More or Less: A Bio-Ecological Treatise on Intellectual Development, Prentice Hall, 1990.
- Richard B. Darlington, "'The Bell Curve'--solid center or abnormal deviate?"
- Bartlett, J., and Byrd, R., "Team teaching verbal, mathematics, and learning skills, Howard University Center for Academic Reinforcement, 1980.
[ix] - Stephen Jay Gould, The Mismeasure of Man, pp. 213-217.