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).

IQ peaks and stops increasing at around 20 years of age and then is mostly fixed for life.

IQ peaks at around 20-years-old and later effort will not improve it much beyond this point, research finds.

The complexity of people’s jobs, higher education, socialising and reading all probably have little effect on peak cognitive ability.

Naturally, these activities have many other benefits, but little influence on intelligence.

However, education is particularly important at an early age when the brain is still developing.

By early adulthood, though, most people’s IQ has settled down.

When IQ is fixed

IQ can increase by as much as 20 points in only four years across the early to late teens, research finds (Ramsden et al., 2011).

During this time young people’s IQ shifts dramatically both up and down.

For the study, 33 adolescents were followed over four years.

Ms Sue Ramsden, the study’s first author, explained the results:

“We found a considerable amount of change in how our subjects performed on the IQ tests in 2008 compared to four years earlier.

Some subjects performed markedly better but some performed considerably worse.

We found a clear correlation between this change in performance and changes in the structure of their brains and so can say with some certainty that these changes in IQ are real.”

Can IQ be increased after this peak?

However, while some studies have suggested that cognitive activities in later life can improve IQ, Professor William S. Kremen, author of one study on the subject, thinks otherwise:

“The findings suggest that the impact of education, occupational complexity and engagement in cognitive activities on later life cognitive function likely reflects reverse causation.

In other words, they are largely downstream effects of young adult intellectual capacity.”

The study included 1,009 men now in their 50s and 60s whose IQ was assessed when they were around 20-years-old.

They were given tests of abstract reasoning, verbal fluency and memory, among with other cognitive measures.

The results showed that most of the difference between the men’s IQs in mid-life was explained by the difference between them at around 20-years-old.

In comparison, the complexity of the job they had, the intellectual activities they engaged in, and their education in the meantime hardly had any effect on their peak IQ.

Brain scans also showed that IQ at age 20 was associated with the surface area of the cerebral cortex.

The cerebral cortex is the brain’s gray matter, the part that performs the higher functions of thinking, perceiving and language.

Most of the benefits of education for peak IQ likely happen before young adulthood, said Professor Kremen:

“Our findings suggest we should look at this from a lifespan perspective.

Enhancing cognitive reserve and reducing later life cognitive decline may really need to begin with more access to quality childhood and adolescent education.”

Maybe IQ does not stop increasing

Not everyone agrees, though, that IQ is fixed, since there is increasing evidence of brain plasticity at later ages.

Perhaps IQ and can peak later and higher?

Professor Cathy Price, who co-authored the study with Ms Sue Ramsden, said:

“The question is, if our brain structure can change throughout our adult lives, can our IQ also change?

My guess is yes.

There is plenty of evidence to suggest that our brains can adapt and their structure changes, even in adulthood.”

The study was published in the journal PNAS (Kremen et al., 2019).

The strongest personality feature of high fluid intelligence.

Being willing to entertain new, unconventional ideas is the strongest personality trait linked to high fluid intelligence, research finds.

Preferring variety and new activities over routine and sameness is also linked to high intelligence, the same survey found.

People with high intelligence are more likely to enjoy philosophical arguments, brain teasers, new problems and eccentric or uncommon activities.

Fluid intelligence refers to the speed at which the brain works.

It is like the raw power of an engine or the speed at which a computer can process information.

In contrast, crystalised intelligence roughly refers to general knowledge.

The study’s authors write that fluid intelligence was…

“…correlated with Actions and Ideas.

[…]

Ideas refers to intellectual curiosity.

This trait is seen as an active pursuit of intellectual interests, and as a willingness to consider new, perhaps unconventional ideas.

High scorers on this scale enjoy philosophical arguments and brain teasers.”

Both actions and ideas are components or ‘sub-factors’ of the personality factor of openness to experience, which is strongly linked to intelligence.

Sub-factors of openness that were not strongly linked to intelligence included ‘fantasy’, ‘feelings’ and ‘values’, suggesting these do not tell us anything about a person’s intelligence.

The findings come from a survey of 2,658 employees at 10 different British companies.

All completed tests of intelligence and personality.

Like an interest in ideas, being willing to try new activities was also linked to intelligence, the authors write:

“Actions refers to willingness to try different activities, and to a preference for novelty and variety over familiarity and routine.

Fluid intelligence involves things like reaction times, quick thinking, reasoning, seeing relationships and approaching new problems.

This means that individuals high on [fluid intelligence] have an innate ability to cope more efficiently with novel experiences, and to deal with intellectually stimulating tasks such as brain teasers, which would thus make it rewarding for them to pursuit such activities.

Similarly, individuals low on [fluid intelligence] may in time grow to avoid such activities, due to their low ability to handle them, which would thus make them less rewarding.”

The study was published in the journal Learning and Individual Differences (Moutafi et al., 2006).

The study tracked 65,765 people born in Scotland in 1936 for 79 years.

People with higher IQs live longer lives, research finds.

People with high intelligence in childhood are less likely to get heart disease, strokes, respiratory diseases and dementia later on.

Some of the lowered risk is down to the fact that more intelligent people are less likely to smoke.

The conclusions come from a study of 65,765 people born in Scotland in 1936 who were followed until age 79.

Higher IQ scores in childhood were linked to a:

• 28% reduction in risk of death from respiratory diseases,
• 25% reduction in risk of death from coronary heart disease,
• and 24% reduction in stroke risk.

The study’s authors write:

“Importantly, it shows that childhood IQ is strongly associated with causes of death that are, to a great extent, dependent on already known risk factors…

…tobacco smoking and its distribution along the socioeconomic spectrum could be of particular importance here.

[…]

It remains to be seen if this is the full story or if IQ signals something deeper, and possibly genetic, in its relation to longevity.”

The study was published in the BMJ (Calvin et al., 2017).

The behaviour is linked to more white matter, the brain’s ‘superhighway’.

People who take calculated risks are likely to be smarter than average, research finds.

People making quick decisions and taking chances have more white matter in their brains.

White matter is sometimes called the ‘superhighway’ of the brain: it transmits signals and regulates communication.

The researchers were surprised by the result as they expected the exact opposite: that smarter people would spend more time evaluating the situation before making a decision.

Dr Dagfinn Moe, study co-author, explained:

“We expected to find that young men who spend time considering what they are going to do in a given risk situation would have more highly developed neural networks in their brains than those who make quick decisions and take chances.

This has been well documented in a series of studies, but our project revealed the complete opposite.”

The research involved young men playing a driving game.

The results showed that high-risk takers did not hesitate as long during the game.

Dr Moe thinks that the ability to take risks is under-appreciated by society at large:

“Daring and risk-willingness activate and challenge the brain’s capacity and contribute towards learning, coping strategies and development.

They can stimulate behaviour in the direction of higher levels of risk-taking in people already predisposed to adapt to cope optimally in such situations.

We must stop regarding daring and risk-willingness simply as undesirable and uncontrolled behaviour patterns.”

Seeking out challenges helps to stimulate the brain, which may be why risk-takers have more white matter.

Dr Moe said:

“All the positive brain chemicals respond under such conditions, promoting growth factors that contribute to the development of the robust neural networks that form the basis of our physical and mental skills.

The point here is that if you’re going to take risks, you have to have the required skills.

And these have to be learned.

Sadly, many fail during this learning process — with tragic consequences.

So this is why we’re wording our findings with a Darwinian slant — it takes brains to take risks.”

The study was published in the journal PLOS ONE (Vorobyev et al., 2015).

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).

“Happiness in intelligent people is the rarest thing I know.” — Ernest Hemingway

People with higher IQs are more likely to be happy, research finds.

The finding goes against both Hemingway and the popular idea that being intelligent is somehow predisposes people to unhappiness.

Dr Angela Hassiotis, who led the study, said:

“We found that IQ is associated with self-reported happiness, as levels of happiness were lowest in the lower IQ groups and highest in the higher IQ groups.

This is particularly relevant when considering the current political debates on happiness.”

For the study, data from almost 7,000 people was analysed.

The results showed that people with the lowest IQ (70 – 99) were the least happy in comparison to those with the highest IQs (120 – 129).

It wasn’t just about IQ, though, as Dr Hassiotis explained:

“When looking at the data we saw that people with a lower IQ were less likely to be happier because of higher levels of socio-economic disadvantage such as lower income.

They are also less likely to be happy because they need more help with skills of daily living, have poorer health and report more symptoms of psychological distress.”

Interventions should focus on increasing IQ levels at a young age, said Dr Hassiotis:

“There is also some evidence that long term intensive strategies directed at young children from socially deprived backgrounds can have a positive impact not only on IQ but also on wellbeing and life opportunities.

Such interventions are likely to be costly but the initial costs may be offset by future benefits such as a reduced reliance on state benefits and better mental and physical health.”

The study was published in the journal Psychological Medicine (Ali et al., 2012).