IQ is the acronym for intelligent quotient, and refers to a score given for several standardized intelligence tests. The first of these was developed by French psychologist Alfred Binet in 1905. He constructed the IQ test, as it would later be called, to determine which children might need additional help in scholarly pursuits. Today, the IQ test is commonly based on some model of the Stanford Binet Intelligence scale.

Not all intelligence can be measured by an IQ test. In fact, primarily, an IQ test measures mathematical and spatial reasoning, logical ability, and language understanding. Thus a person who is speaking English as a second language might score poorly on the language comprehension aspects of a test, and an IQ test would not be an adequate measurement of intelligence.

Further an IQ test does not measure things like life experience, wisdom, or personal qualities like being a good friend or a devoted spouse. So it is not a predictor of a person’s quality or worth, though it has occasionally been used as such.

Some things can negatively impact IQ score. These include malnutrition in children who are tested, and fetal alcohol syndrome, or maternal addiction. Mental retardation or conditions that deteriorate the brain’s capacity to remember like Alzheimer’s disease also causes IQ scores to be lower. IQ may also be impacted by lack of appropriate education, often due to disparity in educational funding. If these disparities are corrected, then IQ scores normally increase.

People can also train to take IQ tests, which can increase scoring. However, it is not known whether a person who scores higher because of training or repeated testing is actually more intelligent. It is verifiable that the trained person does better on the IQ test than the person who is not trained.

There have been some studies on brain size and development and IQ scores. Specifically the frontal lobe of the brain seems to be the most indicative method for prediction of IQ scores. Larger frontal lobes tend to result in larger IQs.

Men and women seem to score approximately the same on IQ testing, though men exhibit a greater variance in testing, and have more very high and very low scores than do women. The American Psychological Association conducted studies on IQs and came up with the following conclusions:

• IQ score was a fairly good predictor for school performance.
• IQ score may also predict fairly well the degree to which a person may be successful in occupations.
• IQ scores tend to exhibit some racial bias.
• Test scores may be influenced by personal genetic history.

There is much contentious debate in evaluating the IQ test, as to whether nature or nurture most influences IQ scores. As well, debate exists as to how much IQ scores should be used as a predictor of behavior. Some are concerned that IQ scores might negatively affect the perception of colleges, private schools or employers if used to determine employability or acceptance into schools.