Both High-, Low-IQ People Drink More

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Intelligent people differ from everyone else in several meaningful ways.

The first is plainly obvious yet somehow still controversial: High IQ people have a different genetic profile. Indeed, intelligence runs in families, and analyses have shown that genetic factors may explain 70 to 80% of the variance in adult intelligence. Second, intelligent people tend to earn more money. And third, the intellectually gifted make different lifestyle choices.

That latter point was the subject of a new paper published in the journal Intelligence, which sought to link intelligence in youth with behavior in middle age. The authors included 5,347 men and women who had taken an IQ test, called the Armed Forces Qualification Test (AFQT), in 1980. At the time, the participants were 15 to 23 years old. In 2012, over 30 years later, the same participants responded to a survey about their lifestyles.

The authors observed several notable patterns. (See figure.) Middle-aged people who had high IQs as youths were likelier to exercise and drink alcohol. (They are also likelier to skip meals, but this relationship is complex and is discussed further below.) On the other hand, people with lower IQs as youths were likelier to have sugary drinks, binge drink, and smoke. There was no relationship between youth IQ and eating fast food in middle age.

The researchers took a closer look at the relationship between IQ and alcohol. In the graph below, the U-shaped curve shows that people with either a low or high IQ as youths drink more alcohol in middle age, while people who had average intelligence drink the least. (See figure below.) This makes sense in light of other findings, namely that higher IQ people tend to drink more (perhaps moderately but more frequently), while lower IQ people tend to binge drink.

An inverted U-shape was found for the association between youth IQ and skipping meals as adults. It is difficult to make sense of this relationship, partially because the U-shaped graph only included people who reported skipping meals. Among people who did, both low- and high-IQ people skipped the fewest meals, while average IQ people skipped the most. (The same inverted U-shape was found among people who smoked. See graph above.)

Overall, this paper adds to the body of literature that characterizes how intelligent people differ from others. Mimicking the behaviors of intelligent people will not make a person intelligent, but it could provide a health boost.

Source: Christina Wraw, Geoff Der, Catharine R. Gale, Ian J. Deary. "Intelligence in youth and health behaviours in middle age." Intelligence 69: 71-86. Published online: 24-May-2018. DOI: 10.1016/j.intell.2018.04.005.