Study finds genetic link between height and IQ

A team of researchers at Edinburgh University in Scotland has found a correlation between genes associated with height and those associated with intelligence. In their paper published in the journal Behavior Genetics, the group describes how they studied the DNA of 6,815 unrelated people and discovered what they describe as a direct correlation between height and intelligence—taller people are smarter, they say.

While the team's study results are likely to cause quite a stir, particularly among those lower in physical stature, it does add to a growing body of research that suggests there are physical, mental and in some cases emotional differences between people related to body size (both height and girth). In this effort, the team used data obtained from Generation Scotland: Scottish Family Health Study—where both medical tests and mental aptitude were tested—intelligence was measured via four basic metrics: mental reaction times, linguistic ability, processing speed and powers of recall.

In analyzing data from the study, the team found what they describe as a "significant genetic correlation" between IQ and height—between taller and shorter people. Those that were shorter were on average, found to be slightly less intelligent than their taller counterparts. It's important to note that the researchers are not suggesting that all short people are less intelligent, or that all tall people are more intelligent. Instead they are pointing out averages across a population. Also important to note is that the Family Health Study did not use standard IQ tests to measure intelligence.

The research team also claim that 70 percent of the genetic differences they found regarding IQ and height could be attributed to genetic factors—the rest could be chalked up to environment.

Other studies have found that there exists different health risks for people of different heights—some have found that shorter people, for example, are more likely to suffer from cardiovascular disease, while taller people tend to die younger than shorter people. Studies that have looked for intelligence differences based on height, however, have been few and far between. The researchers in Scotland point out that prior studies have relied mainly on testing people related to one another—theirs, they claim, is the first study to measure people who are completely unrelated.

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