Category: Intelligence

It is linked to higher IQ and being 30% less likely to suffer major depression.

People who are intelligent are 30 percent more likely to be short-sighted, research finds.

Intelligent people are also 30 percent less likely to suffer from major depression.

The findings are part of a study looking at the genetic underpinnings of intelligence.

The results come from 300,486 people aged 16 to 102 who had their DNA analysed.

The researchers found 148 different genetic locations were linked to cognitive ability.

Smarter people are also likely to have better mental health, a lower risk of cancer and greater longevity.

In fact, intelligent people are 17 percent more likely to live longer.

Dr Gail Davies, the study’s first author, said:

“This study, the largest genetic study of cognitive function, has identified many genetic differences that contribute to the heritability of thinking skills.

The discovery of shared genetic effects on health outcomes and brain structure provides a foundation for exploring the mechanisms by which these differences influence thinking skills throughout a lifetime.”

The search for connections between genes and intelligence has proved difficult.

Professor Ian Deary, who led the study, explained:

“Less than a decade ago we were searching for genes related to intelligence with about 3,000 participants, and we found almost nothing.

Now with 100 times that number of participants, and with more than 200 scientists working together, we have discovered almost 150 genetic regions that are related to how clever people are.

[…]

One thing we know from these results is that good thinking skills are a part of good health overall.”

The study was published in the journal Nature Communications (Davies et al., 2018).

Which hair colour is linked to higher intelligence?

The stereotype has it that blondes, while having more fun, are not as smart.

However, contrary to the stereotype, blonde women have slightly higher IQs than brunettes, a study finds.

However, the difference is so small as to be statistically insignificant.

Blonde men, meanwhile, have similar IQs to men with other hair colours.

So, blondes are not dumb — whether they are male or female.

The point might seem trivial, but the study’s author, Dr Jay Zagorsky, argues that stereotypes can have real-world implications:

“Research shows that stereotypes often have an impact on hiring, promotions and other social experiences.

This study provides compelling evidence that there shouldn’t be any discrimination against blondes based on their intelligence.”

The conclusions come from a survey of 10,878 white Americans asked about their natural hair colour (Hispanics and African Americans were excluded to eliminate bias).

The results showed the average IQ of blonde-haired women was 103.2, 102.7 for brown hair, 101.2 for red hair and 100.5 for black hair.

However, the differences were so small as to be unlikely to represent a real difference.

Dr Zagorsky said:

“I don’t think you can say with certainty that blondes are smarter than others, but you can definitely say they are not any dumber.”

A factor that could explain blondes having higher IQ is that they also had more books in their homes during childhood, Dr Zagorsky said:

“If blondes have any slight advantage, it may simply be that they were more likely to grow up in homes with more intellectual stimulation.”

While the research may reveal little difference, stereotypes are powerful, Dr Zagorsky writes:

“…humans use a person’s looks as a signal for the person’s personality or productivity.

For example, blonde women are often stereotyped as dumb or incompetent while redheads are seen as people with fiery tempers.

These stereotypes are reinforced in popular culture with the dumb blonde female being a staple of Hollywood movies such as Reese Witherspoon in the “Legally Blonde” series or even Marilyn Monroe in “Gentlemen Prefer Blondes.”

The study was published in the journal Economics Bulletin (Zagorsky, 2016).

Study of over 7,000 finds diet linked to IQ.

People fed a healthier diet from an early age have a higher IQ, research reveals.

Children who were breastfed and later given plenty of fruits, vegetables and other healthy foods had IQs up to two points higher at age 8.

Dr Lisa Smithers, the study’s first author, said:

“Diet supplies the nutrients needed for the development of brain tissues in the first two years of life, and the aim of this study was to look at what impact diet would have on children’s IQs.

We found that children who were breastfed at six months and had a healthy diet regularly including foods such as legumes, cheese, fruit and vegetables at 15 and 24 months, had an IQ up to two points higher by age eight.

The results come from a study of over 7,000 children whose eating habits were analysed at ages 6 months, 15 months and two years.

They were followed until age 8.

Set against the benefits of healthy eating, children fed junk food had lower IQs, Dr Smithers said:

“Those children who had a diet regularly involving biscuits, chocolate, sweets, soft drinks and chips in the first two years of life had IQs up to two points lower by age eight.

We also found some negative impact on IQ from ready-prepared baby foods given at six months, but some positive associations when given at 24 months.”

Eating well is particularly important in the formative years, said Dr Smithers:

“While the differences in IQ are not huge, this study provides some of the strongest evidence to date that dietary patterns from six to 24 months have a small but significant effect on IQ at eight years of age.

It is important that we consider the longer-term impact of the foods we feed our children.”

The study was published in the European Journal of Epidemiology (Smithers et al., 2012).

The quality that people with higher IQ tend to have.

Freedom from prejudice is a clear sign that someone has a high IQ, a study finds.

More intelligent people are less likely to be either homophobic or racist, the research found.

On top of this, more intelligent people are also more likely to be trusting of others and sensitive to other people’s needs.

The conclusions come from a couple of studies in which people were given IQ tests and asked questions that probed whether they were prejudiced.

In one survey of 15,874 people in the UK, participants were asked questions like:

• “I wouldn’t mind working with people from other races.”

Their answers to questions like this were compared with IQ tests they had been given as children.

The results showed that people with lower IQs tended to display more overt racism.

A second group of 254 people in the US were asked about their attitudes to homosexuals, as well as being given IQ tests.

Once again, the results showed that people with lower IQs were more likely to be prejudiced against gay people.

The researchers found that in both groups of people, those with lower IQs had lower contact with people from minorities — in this case, races other than their own and gay people.

The study’s authors conclude that:

“…we found that lower general intelligence (g) in childhood predicts greater racism in adulthood a predictive effect of poor abstract-reasoning skills on antihomosexual prejudice, a relation partially mediated by both authoritarianism and low levels of intergroup contact.

Our results suggest that cognitive abilities play a critical, albeit underappreciated, role in prejudice.”

Authoritarianism is a disregard for the feelings and wishes of others.

Unsurprisingly, this was also linked to prejudice.

→ Discover 22 more signs of intelligence.

The study was published in the journal Psychological Science (Hodson & Busseri, 2012).

Intelligent people often value novel things and are at a greater risk of getting bored.

People with high IQs are more likely to consume mind-altering substances, research finds.

Whether it is alcohol, tobacco or psychoactive drugs like LSD, intelligence and drug-taking are linked.

More intelligent people are also more likely to have sampled a variety of different recreational drugs in the past.

The explanation could be that intelligent people are attracted to novelty or that they do not fear becoming addicted due to higher self-control.

The conclusions come from a series of studies conducted around the world.

One looked at data from the UK and the US, tracking childhood intelligence and the drugs people took later in life.

The study’s authors explain the results:

“More intelligent children, both in the United Kingdom and the United States, are more likely to grow up to consume more alcohol.

More intelligent American children are more likely to grow up to consume more tobacco, while more intelligent British children are more likely to grow up to consume more illegal drugs.”

A second study used a survey of 12,686 people in the US who were first interviewed in 1979 and tracked to the present day.

The results showed that:

“…intelligence tends to be positively related to the probabilities of having tried alcohol, marijuana, cocaine and several other recreational drugs.”

One explanation is that more intelligent people value novelty.

But, there are other ideas:

“…more intelligent people may be less concerned about addiction.

More intelligent people tend to be better at self-control and may therefore be better at restricting their consumption of addictive substances

[…]

If more intelligent people anticipate that they will be able to break their addictions, then they may be more likely to try recreational drugs.”

This fits with another recent study that found that people with high IQs drink more alcohol, although they are unlikely to be heavy drinkers.

Another possibility is that more intelligent people are more likely to get bored.

The studies were was published in the journals Review of General Psychology and Intelligence (Kanazawa & Hellberg, 2010; Wilmoth, 2012).