Richard G. Petty, MD

The Evolution of Intelligence


Here we have a conventional approach to the notion of intelligence, by someone whose work I have always admired. But on this I think that he is wrong. I constantly see evidence of multiple types of intelligence in all kinds of animals. To be sure, it is not the kind of cognitive skill picked up “standardized testing” but it is “high intelligence” all the same.

What do you think?

“Nothing demonstrates the improbability of high intelligence better than the 50 billion earthly species that failed to achieve it.”

–Ernst Mayr (German-born American Evolutionary Biologist, 1904-2005)

Resisting Impulses: A Crucial Skill For Everyone!


“There is perhaps no psychological skill more fundamental than resisting impulse. It is the root of all emotional self-control, since all emotions, by their very nature, lead to one or another impulse to act. The root meaning of the word emotion, remember, is “to move.”

–Daniel Goleman (American Psychologist, Journalist, Author and Consultant, 1946-)         

“Emotional Intelligence: Why It Can Matter More Than IQ” (Daniel Goleman)

Mind and Intelligence

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“Mind and intelligence are woven into the fabric of our universe in a way that altogether surpasses our understanding.”

–Freeman Dyson (

English-born American Physicist and Mathematician, 1923-)

Understanding Is Joyous


“We are an intelligent species and the use of our intelligence quite properly gives us pleasure. In this respect the brain is like a muscle. When it is in use we feel very good. Understanding is joyous.”    

–Carl Sagan (American Astronomer and Science Writer, 1934-1996)

“Broca’s Brain: Reflections on the Romance of Science” (Carl Sagan)

Commonsense Ain’t So Common!

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“A man may have intelligence enough to excel in a particular thing and lecture on it, and yet not have sense enough to know he ought to be silent on some other subject of which he has but a slight knowledge; if such an illustrious man ventures beyond the bounds of his capacity, he loses his way and talks like a fool.”           

–Jean de la Bruyère (French Essayist and Moralist, 1645-1696)

Blondes Make Us Dumb??

No, this isn’t just a cheap excuse to display a picture of Pamela Anderson.

I just received this from a regular reader:

“Dear Dr Petty,

Have you seen this article Times Online?

“WHEN men meet fair-haired women they really do have a “blonde moment”. Scientists have found that their mental performance drops, apparently because they believe they are dealing with someone less intelligent.

Researchers discovered what might be called the “bimbo delusion” by studying men’s ability to complete general knowledge tests after exposure to different women. The academics found that men’s scores fell after they were shown pictures of blondes.

Further analysis convinced the team that, rather than simply being distracted by the flaxen hair, those who performed poorly had been unconsciously driven by social stereotypes to “think blonde”.

“This proves that people confronted with stereotypes generally behave in line with them,” said Thierry Meyer, joint author of the study and professor of social psychology at the University of Paris X-Nanterre. “In this case blondes have the potential to make people act in a dumber way, because they mimic the unconscious stereotype of the dumb blonde.”

Do you have any comment to make about the research??”

The answer is that I have seen this article all over the Internet, with all kinds of sage comments.

The trouble is that I have not yet been able to read and critique the research. As far as I know, neither the hard copy nor electronic versions are available yet, so I cannot evaluate the report.

This highlights one of the problems of the Internet: news travels across it like the wind, yet a lot of material is passed on without analysis. So the story is fun to read, but until we can see and analyze the data, we cannot comment.

As soon as I get a copy I shall see if I have anything to add to the firestorm of commentary!

Genes, Breastfeeding and IQ

Studies on intelligence and breastfeeding have come up with conflicting results. The major question has been whether the results have been skewed because more educated or more affluent mothers were more likely to breastfeed.

A new study by colleagues in London, New Zealand and here in the United States has just been published in the Proceedings of the National Academies of Sciences and indicates that a single gene influences whether breastfeeding improves a child’s intelligence.

The gene in which the researchers were interested is a fatty acid delta desaturase – FADS2 – that is involved in the genetic control of fatty acid pathways. Children with one version of the FADS2 gene scored seven points higher in IQ tests if they were breastfed, but breastfeeding had no effect on the IQ of children with a different version of the gene.

Researchers at the Institute of Psychiatry, Kings College London, used data from two previous studies of breast-fed infants in Britain and New Zealand that had involved more than 3,000 children. IQ was measured at various points between the ages of five and 13 years in the studies. The only thing that we do not know is exactly how long the children were breastfed.

This is yet another study to show us why the nature/nurture debate needs a radical re-think. Nutrition and genetics act together. People have been arguing about the roots of intelligence for at least a hundred years, and this research shows nature working via nurture to create better outcomes.

Around 90% of people carry the version of the gene that was associated with better IQ scores in breastfed children. We do not know if there are any ethnic differences in those numbers, but there may be.

And that seven point difference in IQ? It s not going to determine how well someone is going to do in life, but in school it might be enough to put the child in the top third of the class.

Birth Order, Social Order and Intelligence

For many decades, experts have disagreed about the impact of birth order on intellect, achievement and emotional and cognitive skills.

Some have claimed that first-born children get more undivided attention from their parents and so develop faster and become more cognitively competent.

Others have claimed that birth order might have an impact because of differences in the womb before birth. The idea was that with each subsequent pregnancy the mother produces higher and higher levels of antibodies that may attack the fetal brain.

Other researchers claim that the relationship between birth order and intelligence is false, having been biased by family size. Historically there has been a tendency couples with lower IQs to have more children than couples with higher IQs. But that is also hard to support: there are many cultures and religions in which high IQ couples have many children.

Three years ago, Dalton Conley, a sociologist from New York University and director of the Center for Advanced Social Science Research published a fascinating book, The Pecking Order, in which he used data from the U.S. Census, the General Social Census Survey conducted at the University of Chicago over the last thirty years, as well as a prospective study launched in 1968, at the University of Michigan. He came to the conclusion that siblings diverge widely in social status, wealth and education. We can all remember examples in the news: of a President with a drug using brother and a professor whose brother was a convict. There are scores of other cases like these.

In Dalton’s model, there are genetic, social and birth order reasons for these family inequalities. Most families establish a hierarchy that predicts a child’s success and role within a family. Where you are in that hierarchy is only partly determined by birth order. Dalton argued that what really matters is family size, parental time and attention, and how much of the family’s financial resources are available for the child. His research showed that no single factor could predict success or failure in life. That makes good sense, though when we look at family hierarchies there is likely a strong cultural and ethnic factor at play. In some cultures first-born boys still receive a great deal more favoritism than the other children.

Now a Norwegian team has reported in the journal Science that first born children and those who had lost older siblings and had thereby become the eldest, scored higher on standard tests of intelligence. The IQ difference that they found in their study groups was small but significant.

The link was found by Professor Petter Kristensen at the National Institute of Occupational Health in Oslo, and Tor Bjerkedal at the Norwegian Armed Forces Medical Service who looked at more than 250,000 male Norwegian conscripts.

What they found in this large all male group was that it is the son’s social position in a family rather than his biological position that counts toward his intelligence.

For example, if a man was born third but then lost an elder sibling in early childhood, he would normally be raised as if had been born second. And his IQ as an adult would tend to be close to that of “genuine” second-borns.

It is going to be interesting to see whether there is a similar effect in girls, since they tend to grow up more quickly than boys.

The fact that the death of an older sibling “moves the child up” the IQ rankings is against something going on in the womb.

There are several possible reasons for this effect. More mature children often tend to become a surrogate parent. And because he or she is still young they will tend to become very conscientious, mature and self-disciplined. You have probably seen or known of a child who had to do a lot of growing up very quickly after the death of, or abandonment by, a parent.

Another possibility is that a first-born gets smarter because he or she tutors the younger siblings.

A complicating factor in this research is when a child “moves up” because of the death of an older sibling, the shock of losing a child may lead the family to expend even more care and attention on the surviving children, particular those most likely to be able to take over if anything happens to the parents.

And the other point I something that I have discussed before. There are genes that predispose you to having a certain type and degree of intelligence. But social and environmental factors continue to have a powerful impact.

I just read an article in which the parents of some mentally ill people were declaring that new research on the social triggers to mental illness was a waste of time, and that the “Answer” must be biological.

It is rarely that simple: genes, epigenetic factors, nutrition, personal experience and the social and emotional environment all need to be put into the mix if we want to understand why someone is the way that they are, and how we can help them to fulfill their potential.

Dogs, Infants and Imitation

Human beings have a remarkable ability to be able to understand the goals and intentions of others. This ability develops gradually during infancy and early childhood and is known as the theory of mind. This ability seems often to go wrong in people with autism spectrum disorders and schizophrenia. Psychologists have tended to think that this is a purely human ability, yet every one who spends a lot of time with animals is sure that they have a similar ability.

New research from the University of Vienna and the University of Budapest, have found striking similarities between humans and dogs in the way they imitate the actions of others.

The researchers were examining a phenomenon known as “selective imitation.” Dogs were given the task of opening a food container by pulling a rod. Normally dogs prefer to use their mouths for this kind of task, but a female dog was trained to open the box with her paw. When the other dogs watched how she did it, they imitated her to get the food. But the dogs only imitated selectively.

When the “training dog” used her paw while holding a ball in her mouth, they used their mouths instead of their paws for manipulating the rod. But when the demonstrating dog’s mouth was free, the dogs once again imitated her and used their paws. This implies that they assumed that she was only using her paw because her mouth was otherwise occupied.

It also indicates that dogs are like human infants in that they do not simply copy an action that they observe, but they adjust the extent to which they imitate depending on the situation. Neither dogs nor humans blindly copy what another creature is doing: they copy what is appropriate for the task at hand. The research has just appeared online in the journal Current Biology.

After their millennia of association with humans, dogs may be a special case. But I doubt it: this is yet more evidence that the gap between animals and humans is shrinking much more rapidly than many of us realize.

Heavy Metal and Clever Teenagers

You humble reporter loves music: anything from Mozart to Metallica.

She Who Must Be Obeyed is one of many people who has wondered at my enthusiasm for bands like Iron Maiden and Metallica. Was I, perhaps, dropped on my head as a child?

I was gratified to see a report of a study that was presented at a recent meeting of the British Psychological Society in York, indicating that intelligent teenagers often listen to heavy metal music to cope with the pressures associated with being talented.

Though sadly your humble reporter is no longer a teenager, the seeds of his enthusiasm for this kind of music were sown many years ago.

Stuart Cadwallader and Professor Jim Campbell of The National Academy for Gifted and Talented Youth at the University of Warwick looked at 1,057 students
aged between 11 and 18 years old who completed a survey asking them
about family, school attitudes, leisure time pursuits and media
preferences. They also asked them to rank favored genres of music.

They found that rock was the most popular form of music, closely followed by pop.

Researchers found that, far from being a sign of delinquency and poor academic ability, many adolescent “metalheads” are extremely bright and often use the music to help them deal with the stresses and strains of being gifted social outsiders.

Stuart Cadwallader has this to say,

“There is a perception of gifted and talented students as being into classical music and spending a lot of time reading. I think that is an inaccurate stereotype. There is literature that links heavy metal to poor academic performance and delinquency but we found a group that contradicts that… Participants said they appreciated the complex and sometimes political themes of heavy metal music more than perhaps the average pop song. It has a tendency to worry adults a bit but I think it is just a cathartic thing. It does not indicate problems.”

There was something about the metal heads having lower self-esteem and more difficulties in family relationships, but your humble reporter isn’t too sure about that bit….

But here’s the important thing: all things in moderation. A lot of loud heavy metal music may not be good for your health. The data is anecdotal, and comes from sources like the Emoto experiments with water crystals, that have still not been replicated.

But as a rule of thumb, some occasional loud music probably never hurt anyone unless they turned up the volume too high. Listening to it all day long could be damaging to your health.

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