Category: Intelligence

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).

The more of the foods they consumed, the higher their IQs.

A diet low in sugars, fats and processed foods consumed at a young age may increase your intelligence, research finds.

Children under 3-years-old fed diets that are packed full of nutrients and vitamins have higher IQs.

The more healthily they eat, the higher their IQ.

The study followed the wellbeing and health of 14,000 children born between 1991 and 1992 in the UK.

What they ate was tracked up to the age of 8, when they were given an intelligence test.

The results showed that children who ate a health-conscious diet including more salad, rice, pasta, fish and fruit had higher IQs at age 8.

Those consuming more junk food high in fats and sugars had lower IQs.

The study’s authors conclude that:

“…a poor diet associated with high fat, sugar and processed food content in early childhood may be associated with small reductions in IQ in later childhood, while a healthy diet, associated with high intakes of nutrient rich foods described at about the time of IQ assessment may be associated with small increases in IQ.”

There was little effect on IQ from what children ate between ages 4 and 7.

The authors say:

“This suggests that any cognitive/behavioural effects relating to eating habits in early childhood may well persist into later childhood, despite any subsequent changes (including improvements) to dietary intake.

It is possible that good nutrition during this period [under 3 years-old] may encourage optimal brain growth.”

The study was published in the Journal of Epidemiology and Community Health (Northstone et al., 2011).

The foods boosts fluid intelligence, which is the speed at which the brain works.

Eating organic food is linked to a higher IQ, a study finds.

School-age children who ate more organic food had higher scores on tests of fluid intelligence and working memory.

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.

Working memory, meanwhile, is vital to holding pieces of visual, verbal or other information in your mind while you manipulate them.

Better working memory has been linked to improved learning, attention and other vital outcomes.

The higher levels of nutrients in organic foods may account for the boost to IQ, said Dr Jordi Júlvez, study co-author:

“Healthy diets, including organic diets, are richer than fast food diets in nutrients necessary for the brain, such as fatty acids, vitamins and antioxidants, which together may enhance cognitive function in childhood.”

In contrast, eating fast food, being exposed to tobacco smoke and house crowding were all linked to lower scores on tests of fluid intelligence.

Children’s brains are sensitive

The results come from over one thousand children aged 6 to 11-years-old in six different European countries, including the UK and Spain.

The research examined 87 factors that the unborn child might be exposed to along with another 122 factors that could affect them during childhood.

The brain is still developing in childhood, so it is particularly sensitive to toxicity.

Low levels of toxicity that may have little affect on the adult brain can still influence children’s brains.

Dr Jordi Júlvez, study co-author, explained the main predictors of higher IQ:

“In our study, we found better scores in fluid intelligence and working memory with higher organic food intake and lower fast food intake.”

As for the predictors of lower IQ, Professor Martine Vrijheid, study co-author, said:

“We observed that several prenatal environmental pollutants (indoor air pollution and tobacco smoke) and lifestyle habits during childhood (diet, sleep and family social capital) were associated with behavioral problems in children.”

The study is notable because of its comprehensive approach to a huge range of variables, said Professor Vrijheid:

“One of the strengths of this study on cognition and the earlier study on behavioral problems is that we systematically analyzed a much wider range of exposure biomarkers in blood and urine to determine the internal levels in the model and that we analyzed both prenatal and childhood exposure variables.”

→ Other dietary changes linked to high IQ include nuts, a diet low in sugars, fats and processed foods, fruits and vegetables,

The study was published in the journal Environment International (de Bont et al., 2021).

A range of positive traits like this one are linked to higher intelligence.

People with higher IQs are less aggressive and tend to follow the rules, research suggests.

Since higher intelligence is linked to better behaviour, intelligent people are less likely to steal and cheat.

In contrast, younger people with lower IQs are more likely to alarm and harass others, as well as taking part in antisocial behaviour.

Antisocial boys typically have IQ scores 10 points lower than their more social peers.

The insights come from a study of over 1,116 pairs of twins in the UK.

The children were given tests of externalising behaviour and IQ.

Externalising behaviour refers to stealing, cheating, physical aggression and rule-breaking.

The study’s results showed that higher IQs were linked to lower levels of externalising behaviours.

Naturally, lower IQs were linked with more antisocial behaviour.

The study’s authors write:

“Low IQ is a consistent risk factor for emergence and continuity of antisocial behavior across the life course in both prospective and cross-sectional studies, even when other relevant risk factors are statistically controlled.”

Both genetic and situational factors are likely important in the link, the study’s authors write:

“…cognitive deficits might promote antisocial behavior if children with low IQs misunderstand rules, find it too difficult to negotiate conflict with words, find school frustrating, or become tracked with antisocial peers.”

Studies have also linked other positive traits to higher intelligence.

For example, one study has found that being cooperative is a sign of high intelligence.

Cooperative people are good at learning from experience and seeing the bigger picture.

They are generally helpful, mutually supportive and believe in teamwork.

More intelligent people tend to cautiously trust others at first and then build on this over time.

This helps them cooperate better in the long-run, the researchers found.

The study was published in the Journal of Abnormal Psychology (Koenen et al., 2008).