8 Reasons for Doubting Claims of the Heritability of Intelligence

How much, if any, is intelligence inherited? We can imagine two extreme scenarios. Under the scenario of 0% intelligence heritability, two parents who both had an IQ of about 130 would have no reason at all for thinking that their children would have an IQ above 100. Under the scenario of 100% intelligence inheritability, two parents with an IQ of about 130 could be certain that their children would have an intelligence about the same as their parent's intelligence. It is often claimed that the heritability of intelligence is about 50%. If that were true, two parents with an IQ of about 130 would have a fairly strong reason for suspecting that their children's intelligence would be above average, but not have anything close to certainty about such a matter.

But the claim that intelligence is even 50% inheritable is unproven. I will explain some reasons for doubting such a claim. I will argue that we do not have very convincing evidence that the genetic heritability of intelligence is much higher than 0.

Reason #1: The Lack of Large Parent-Child IQ Databases Needed to Prove a Claim of Intelligence Heritability

What would you need to firmly establish a claim that intelligence is 50% heritable? You would need a very large database listing the IQ scores of very many thousands or millions of individuals, along with the IQ scores of their parents. But such a database is not known to exist anywhere. Consider a case such as my own family. I have never formally had my IQ tested, nor have my two children. When I was in high school, I was told that students had their IQ tested by the school. Conceivably somewhere in some school's database might be an IQ score for me, and in some other school's database might be IQ scores for my children. But there is no database that links these records together, allowing a researcher to use the information as part of a deduction about the heritability of intelligence. The few studies that have attempted to gather the IQ of both parents and children have usually involved samples of no more than a few thousand parents and children. It is impossible to draw very reliable conclusions about human intelligence in general from samples so small.

The study here claims to have used a large database of IQ scores from Norway, one that included parent and child relationships. I'll discuss in the next paragraph why this wasn't actually a database of IQ scores. The study concludes, “The correlation we observe between father’s IQ and that of his son is .38 .” That's an estimate below the typical estimate of 50% for the heritability of intelligence. But since the paper fails to specify how these parent and child relationships were derived, we should be skeptical of this result. The paper is sketchy in its details, and does nothing to tell us: exactly how did the authors know how to connect fathers and sons? We are not even told how many father-son pairs were used. In a large data set with lots of information, someone might use a computer program to scan the data and do a calculation of the correlation between father's IQ and son's IQ. But a single line of errant code in such a computer program would cause the program to produce the wrong answer.

Also, the paper tells us that a standard IQ test was not even the basis of these supposed “IQ scores,” and that the “IQ scores” were derived from a trio of tests. The paper tells us, “The IQ measure is a composite score from three speeded IQ tests -- arithmetic, word similarities, and figures...the word test is similar to the vocabulary test in WAIS.” That doesn't sound like a reliable way at all of testing IQ, and sounds largely like a way of testing education rather than intelligence. The source here says the vocabulary part of the WAIS test "measures word knowledge," but a good IQ test isn't supposed to measure knowledge. The paper seems to have wrongly described a trio of cognitive and educational tests as being an IQ score. We therefore should have no confidence that the paper has informed us about the heritability of IQ.

Reason #2: The Low Reliability of Twin Studies

Lacking what they need (very large databases with the IQ scores of both parents and children), scientists have tried to rely on much smaller databases involving the IQ scores of twins. The strategy of this type of study is as follows:

1. Collect data relevant to the IQ scores of twins.
2. Attempt to figure out whether the twins were monozygotic (so called “identical twins”) or dizygotic twins.
3. Look and see whether there is a closer correlation between the IQ scores of the monozygotic twins and the IQ scores of the dizygotic twins.

The largest study I have found of this type is one that uses something called the Genetics of High Cognitive Abilities (GHCA) Consortium, That term seems to be merely an umbrella used to collect the data from six different studies done in different countries. The number of twins in the database was about 11,000. Based on somewhat higher correlations in IQ between monozygotic twins than in dizygotic twins, the study estimated that intelligence is about 50% heritable.

There are several reasons why such a result is not terribly convincing.

1. Studies such as this are usually run by researchers interested in proving a genetic basis for intelligence. There are any number of ways in which bias might have influenced the studies, such as in decisions on which twins to include.
   
2. A large fraction of the data on whether twins were monozygotic twins was made from parent questionnaires rather than biological DNA testing. Such questionnaires are less reliable than DNA testing.
   
3. The study's paper tells us that the IQ of the twins was estimated by the people running the study (sometime from two or more other tests taken). But were the people doing such estimates blind as to whether the twins were monozygotic or dizygotic? If not, such people might have had a tendency to give similar IQ scores to monozygotic twins. The study makes no mention of a blinding protocol being used. 
4. We are not entitled to draw conclusions about the heritability of intelligence in the general population from studies involving only twins. There could be any number of reasons why the heritability of intelligence is a much different number when twins are involved, particularly since we do not at all understand where intelligence comes from and whether it is actually a product of the brain (there being many reasons for doubting claims that human minds are created by the brain).
5. It is clear from the scientific paper that IQ scores were often derived from written tests in which vocabulary knowledge played an important part. Such tests are largely measures of learned knowledge, something different from intelligence. 

Reason #3: The Sometimes Poor Research Record of Scientists Looking for Genetic Associations

In considering the question of whether intelligence is highly heritable, we should consider the research record of geneticists attempting to show genetic associations with human traits. Over the years such scientists have raised many false alarms, claiming that there were genetic associations when there wasn't good evidence for such a thing. One example of a blunder by such scientists was described in a recent article in The Atlantic entitled “A Waste of 1000 Research Papers.” The article is about how scientists wrote a thousand research papers trying to suggest that genes such as SLC6A4 were a partial cause of depression, one of the leading mental afflictions. The article tells us, "But a new study—the biggest and most comprehensive of its kind yet—shows that this seemingly sturdy mountain of research is actually a house of cards, built on nonexistent foundations." There have been many such cases in which scientists tried to convince us that some factor has a genetic link, but the evidence was weak.  An article says, "Prior to 2005, the field was largely a scientific wasteland scattered with the embarrassing and wretched corpses of unreplicated genetic association studies, with barely a handful of well-validated genetic risk factors peeking above the noise." 

It seems that when scientists are eager to show that there is some genetic basis for something, they can be guilty of analysis bias that causes them to think there is a good evidence for a genetic link when no such evidence exists. Such an example should make us wonder whether the same faulty biased analysis is at work in studies trying to show a link between genes and intelligence.

Reason #4: The Flynn Effect Contradicts Claims That Intelligence is Highly Heritable

The Flynn effect is a well-documented effect that involves a gradual increase in performance in intelligence tests. The increase seems to be about 3% per decade, and has seemingly been occurring since the 1930's (although in some countries in recent years we have failed to see evidence of such a thing). Given how often mothers in their thirties have children in recent decades, what this means is that a child born around 1990 may typically have an IQ 9% greater than the IQ of his parents. Such a thing is a point against claims that intelligence is heritable.

In some of the studies involving the heritability of intelligence, we see a kind of “Flynn effect subtraction” in which the data is massaged to factor out the Flynn effect, or a calculation formula is modified to remove the Flynn effect. But there is no justification for such a thing, which can be described as a kind of cover-up to get rid of a data effect that is inconsistent with the claim of a heritability of intelligence.

Reason #5: The Fact That There Is No Clear Evidence of Any Genes for Intelligence, and That No “IQ Gene” Has Been Found

To try to show a genetic basis for intelligence, scientists sometimes run what is called a genome-wide association study or GWAS. Some of these studies have claimed to have found genes that were associated with intelligence. But there are several reasons why such a thing does not itself show that genes determine intelligence.

Let us consider the important fact that a GWAS will usually find evidence for any thing that is being looked for, purely because of random variations unrelated to a causal effect.  For example, let's suppose you do a study in which you scan the genomes of 10,000 people and try to find correlations with the DNA in these people and their favorite songs.  You will inevitably be able to find some slight correlations here and there which could be cited as a genetic basis for your song preferences. But such an association would be spurious, and would be caused by mere random variations that did not have a causal effect. Your genes don't code your song preferences.

The same type of spurious association could be cropping up in studies trying to link genes to intelligence. So we may ask questions such as this:

(1) How much of a replication effect is there, with the same genes showing up in multiple studies trying to find genes for intelligence?

(2) How strong an association is reported? How much of intelligence variation might be attributable to a particular candidate for an intelligence gene?

Typically there are only weak associations found in such GWAS studies on the heritability of intelligence. For example, an article on one study says, "Even if a person had both copies of all the variants, she would score an average of 1.8 higher points in an IQ test."

As for replication, reports of "intelligence genes" generally do not replicate well. A scientific study attempted to replicate reported associations with some genes (DTNBP1, CTSD, DRD2, ANKK1, CHRM2, SSADH, COMT, BDNF, CHRNA4, DISC1, APOE, and SNAP25) using " using data sets from three independent, well-characterized longitudinal studies with samples of 5,571, 1,759, and 2,441 individuals." The replication attempt failed, and the study is entitled,  "Most reported genetic associations with general intelligence are probably false positives."

An article by a psychologist states the following:

"It’s the best kept secret of modern science: 16 years of the Human Genome Project suggest that genes play little or no role in explaining differences in intelligence. While genes have been found for physical traits, such as height or eye colour, they are not the reason you are smarter (or not) than your siblings. Nor are they why you are like your high-achieving or dullard parents, or their forebears."

Reason #6: The Intrinsic Implausibility of Claims That Genes  Determine Intelligence

Scientists have no understanding of how neurons can create thinking, imagination, abstract ideas or understanding. The claim that human thinking comes from the brain is a speech custom of scientists, rather than a fact established by observations.  There are actually strong reasons for doubting that the brain is the cause of human intelligence. One very strong reason is that when people undergo hemispherectomy operations (in which half of their brain is removed to stop epileptic seizures), it has little effect on their intelligence (as documented here).  In the same link just given, you can read about people with high intelligence despite losing the great majority of their brains.  Because we have such strong reasons for doubting that the brain is the actual source of human intelligence, it is intrinsically implausible that some genes relating to the brain may have a large effect on intelligence. 

Reason #7: Much of the Reported Heritability of Intelligence May Be a Heritability of Dyslexia (or Similar Perception Problems) Unrelated to General Intelligence

Dyslexia is a reading disorder that is believed to affect 5% to 10% of children. Dyslexia is not a defect in general intelligence, and a person with dyslexia will do just as well as a person without dyslexia on an intelligence test that does not require reading. "Dyslexia independent of IQ" is the headline of a story at the MIT News.   Dyslexia is believed to be a highly heritable. A scientific paper on dyslexia says, “Inherited factors are estimated to account for up to 80%.”

But almost all data on IQ comes from paper-and-pencil tests requiring reading. A large part of the data suggesting a heritability of intelligence may simply be caused by a heritability of dyslexia that has nothing to do with intelligence. This is what scientists call a “confounding factor,” and in the case of the heritability of intelligence, it seems to be a largely overlooked confounding factor.

Reason #8: The Fact That IQ Tests Are Imperfect Measurements of Intelligence

It has long been pointed out that IQ tests are far-from-perfect as measurements of intelligence.  One reason is that many things other than intelligence can affect scores on IQ tests. Here are some of the things:

(1) Visual perception. Since an IQ test uses a test booklet that requires a lot of reading, a person's vision clarity and visual perceptual abilities can affect the scores -- but such things are different from intelligence.  If a student comes from a poor family that lacks money to keep his vision at 20/20, so much worse will the student's IQ score be.
(2) Manual dexterity. A typical IQ test will require many different cases of filling in exactly the right oval on a test form, and a small percentage of students might be relatively slow at such a manual task, for reasons having nothing to do with intelligence. 

(3) Learned vocabulary. IQ tests are supposed to use simple words, to avoid being tests of learned knowledge. But any test with many written question must inevitably be partially a test of learned vocabulary.  For example, when I went to the web site for the Wechsler IQ test, the first question (in the short sample test I tried) uses the word "contradictory" and the word "enhance." Very many school children would not know the meaning of these words.  
(4) Motivation. Scores on IQ tests are strongly affected by the degree of motivation of the test taker.  According to this page, when students are offered money rewards for high scores, it will affect the IQ scores by an average of 20 points. We read, "Thus rewards higher than $10 produced g values of more than 1.6 (roughly equivalent to more than 20 IQ points), whereas rewards of less than $1 were only one-tenth as effective."  So imagine the students in a low-quality school where students may tend to have lower motivation.  The average IQ result at such a school might be much lower than the average IQ result at a better school, even if the students at the schools have the same intelligence. 
(5) Dyslexia. This perceptual reading disorder (not an intelligence defect) can drastically affect scores on written IQ tests.
(6) Distractions in test rooms. This can have a large affect on IQ scores. Let's imagine a disorderly school, with quite a few "class clowns" or unruly students. Such students might create any number of distractions that might affect the concentration of students taking IQ tests. 
(7) Number of sharpened pencils of test takers. At a school with students from richer families, an average student may have two sharpened pencils for his IQ test. But at a school with students from poor families, an average student may have only one not-very-sharp pencil.  If the pencil breaks, so much worse for his IQ score. 
(8) Percentage of sick test takers.  A test taker will probably do worse on an IQ test if he is sick.  In affluent communities, parents might hire a "baby sitter" if their child is sick, preventing him from being present during an IQ test. In poorer communities, the sick student might be much more likely to be told to go to school even when he's sick. In some third-world countries,  we can easily imagine 5% or more of the IQ test takers being sick. 
(9) Number of recent traumas affecting test takers. Let's imagine student Sally sits down for a 90-minute IQ test at her school. She finds it rather hard to concentrate very hard for 90 minutes because her thoughts drift to the recent gunfire in her neighborhood, or the alcoholism or drug abuse of one or her family members.  The result may be a lower score on the test. 

The factors discussed above cast great doubt on claims of the heritability of intelligence. The same factors (particularly the ones discussed under Reason #8) are reasons casting great doubt on all claims that people of one race or nationality are (on average) more intelligent or less intelligent than people of some other race or nationality. 

We can imagine a radically different type of intelligence test. A person would be placed in a basement room with a small window three meters above the ground. There would be 20 large filled boxes in the room.  The person would be told that he is being locked in the room, and that he must escape. He would be told that the faster he escapes, the more money he will make. The test would be to see how fast the person can think of stacking the boxes to make a stair-like structure that can be used to allow escape through the window.  On such a test we can easily imagine students from poorer, troubled schools getting scores just as high as students from elite schools. 

I don't rule out the possibility that intelligence is to some degree heritable, although I think there is no strong evidence for a very large amount of such heritability.  We can certainly imagine some possibilities that might one day firm up that type of evidence, including better intelligence tests with fewer confounding variables, and larger databases tracking intelligence scores for parents and their children. 

Postscript: See the link here for a lengthy discussion of the work of Leon J. Kamin, who made a strong critique of twin studies used to bolster claims of a heritability of intelligence.  Below is an excerpt:

 In summing up his TRA study findings in The Science and Politics of I.Q., Kamin wrote, “To the degree that the case for a genetic influence on I.Q. scores rests on the celebrated studies of separated twins, we can justifiably conclude that there is no reason to reject the hypothesis that I.Q. is simply not heritable.” He reached a similar conclusion in relation to IQ genetic research as a whole. Kamin was not concluding that heredity had no influence on IQ test scores, but rather that IQ genetics researchers, who bore the burden of proof, had failed to provide scientifically valid evidence that it did. In a 1976 book review, Harvard evolutionary geneticist and Kamin’s future collaborator Richard Lewontin wrote that Kamin had discovered, in IQ genetic research, “a pattern of shoddiness, carelessness, miserable experimental design, misreporting, and misrepresentation amounting to a major scandal.”

One of the studies most enthusiastically cited by those claiming intelligence is highly heritable is a 1990 Minnesota study of twins reared apart, called MISTRA. The study is debunked by a lengthy 2022 scientifc paper by Jay Joseph entitled "A Reevaluation of the 1990 'Minnesota Study of Twins Reared Apart' IQ Study." We read this:

"In 1980, sociologist Howard Taylor described what he called 'The IQ game,' by which he meant IQ-genetic researchers’ 'use of assumptions that are implausible as well as arbitrary to arrive at some numerical value for the genetic heritability of human IQ scores on the grounds that no heritability calculations could be made without benefit of such assumptions' (Taylor, 1980, p. 7). The MISTRA IQ study can be seen as an exemplar of 'IQ game' bad science...The MISTRA IQ study failed to discover evidence that genetic factors influence IQ scores and cognitive ability across the studied population.".

Study Shows No Clear Link Between Brain Parameters and Intelligence/Knowledge

An interesting recent scientific paper was entitled “The Neural Architecture of General Knowledge.” That title was inappropriate, because the study found no substantial evidence that brains of highly knowledgeable people are different from less knowledgeable people, or that the brains of intelligent people are different from the brains of less intelligent people.

The study collected brain scans of 324 people, and also tested those people for their intelligence and general knowledge. This is a good sample size, so I won't be able to make the complaint that I frequently make about neuroscience studies: the complaint that the sample size was so small there was a high chance of a false alarm. 

The scientists attempted to derive scores for several brain parameters, including the following:

GMV: grey matter volume in the brain.

WMV: white matter volume in the brain.

“NETstruc:” global efficiency of the brain's structural network.

“NETfunc:” global efficiency of the brain's functional network.

There is no generally accepted algorithm for computing the last two of these things, so the numbers that were calculated were somewhat arbitrary.

Below are the correlation coefficients (r) that the study found:

First Parameter	Second Parameter	Correlation	Extent of Correlation (Using Rule of Thumb Cited Below)
GMV (grey matter volume in brain )	“Fluid intelligence”	R= .18	Negligible
GMV (grey matter volume in brain )	General knowledge	r=.12 'The association between general knowledge and GMV failed to reach statistical significance after Bonferroni correction was applied.”	Negligible
WMV (white matter volume in brain)	“Fluid intelligence”	R = .11 “We observed no significant correlation between fluid intelligence and WMV.”	Negligible
WMV (white matter volume in brain)	General knowledge	r=.10 “General knowledge was not significantly associated with WMV.”	Negligible
“NETstruc:” global efficiency of the brain's structural network.	“Fluid intelligence”	R=.13 “The association between fluid intelligence and NETstruc lost its statistical significance after we accounted for multiple comparisons.”	Negligible
“NETstruc:” global efficiency of the brain's structural network.	General knowledge	R=.19	Negligible
“NETfunc:” global efficiency of the brain's functional network.	“Fluid intelligence”	R=.15	Negligible
“NETfunc:” global efficiency of the brain's functional network.	General knowledge	R= .09 “General knowledge was not significantly associated with ... NETfunc.”	Negligible

The scientists made eight different comparison trying to find a correlation between some general brain parameter on the one hand and either intelligence or knowledge on the other hand. All of these comparisons found only correlations less than .2, all of which are negligible according to the rule of thumb cited below. 

The authors of the study apparently followed a  policy that any correlation coefficient of .15 or greater should be announced as a "significant" correlation. But correlation coefficients between .15 and .20 are more accurately described as "negligible." In the scientific paper entitled, “A guide to appropriate use of Correlation coefficient in medical research,” we read the following: “A correlation coefficient of 0.2 is considered to be negligible correlation while a correlation coefficient of 0.3 is considered as low positive correlation.” Below is Table 1 from that paper, which has the heading of "Rule of Thumb for Interpreting the Size of a Correlation Coefficient."

Size of Correlation	Interpretation
.90 to 1.00 (−.90 to −1.00)	Very high positive (negative) correlation
.70 to .90 (−.70 to −.90)	High positive (negative) correlation
.50 to .70 (−.50 to −.70)	Moderate positive (negative) correlation
.30 to .50 (−.30 to −.50)	Low positive (negative) correlation
.00 to .30 (.00 to −.30)	negligible correlation

If you do a Google image search for "correlation coefficient interpretation," you will find several tables or guidelines that list all correlation coefficients of 0.2 or less as either "negligible," "very poor," or "very weak," and some of them (like the table above) actually list all correlation coefficients of .3 or less as "negligible."  Since all of the main eight correlations found by the "Neural Architecture of General Knowledge" paper (listed in the first table of this post) are all correlations of less than .2, they should all be classified as negligible correlations. 

Below is an example of a negligible correlation of only .19, the same as the highest correlation found in the table above listing results from the "Neural Architecture of General Knowledge" scientific paper in question.  Using this page of the "Spurious Correlations" we site, you can graph many other equally negligible correlations. 

Here is another example, showing a correlation of only .20:

The very tiny effects found in the study can easily be explained solely by differences in perceptual speed and manual dexterity of test-takers, differences having nothing to do with intelligence, knowledge or memory. Any paper-and-pencil written test of intelligence or general knowledge is at least 5%  a test of perceptual speed and manual dexterity, which crucially affects the scores on written tests.  

By finding only negligible correlations between brain parameters and intelligence, and by finding only negligible correlations between brain parameters and general knowledge, the scientific study in question is quite consistent with what I have long asserted: that the human brain is not the source of human intelligence, and that the human brain is not the storage place of human memories.  See here for the many reasons I have for making such assertions. 

Similar results came from a 2017 study that studied the correlations between grey matter volume in the brain and performance scores on six cognitive tests.  The study was entitled, "Global associations between regional gray matter volume and diverse complex cognitive functions: evidence from a large sample study." For each of the six cognitive tests, more than 1000 subjects were used (as we can see in Table 1). Table 2 of the study shows that it found only negligible correlations between grey matter volume and the scores on these six tests. The correlations were only 0.032, 0.101, -0.080, 0.088, 0.074, and 0.032, all negligible. 

There are some problems with the ""Neural Architecture of General Knowledge" scientific paper that anyone attempting a replication should try to avoid:
(1) The study paper makes no mention at all of any blinding protocol, meaning that the scientists analyzing brain parameters might have known about the intelligence scores and knowledge scores corresponding to the brains they were analyzing.  Those who made such an analysis should have had no knowledge of such intelligence scores and knowledge scores, to avoid analysis bias (the meager effects reported might have been entirely due to such a lack of a blinding protocol). 
(2)  The authors should have done a pre-registered study in which they committed themselves (before data collection) to exact algorithms of measuring brain connectivity, white matter volume and grey matter volume (rather than having the freedom to adjust such methods until a slight correlation was obtained). 
(3) The test subjects should have been tested for perceptual speed and manual dexterity, with the intelligence scores and knowledge scores adjusted to account for perceptual speed differences and manual dexterity differences that can affect paper-and-pencil test scores (something which may be the sole cause of the very slight effects reported). 

What Is Increasing Human Intelligence?

The Flynn effect is a well-documented effect that involves a gradual increase in performance in intelligence tests. The increase seems to be about 3% per decade, and has seemingly been occurring since the 1930's. Some of the implications are startling -- for example, that before many decades have passed, the average person living will have an intelligence level of the average Harvard freshman today.

There have been various attempts to naturally explain the Flynn effect, but none have been very convincing. One attempted explanation has been that nutrition has been better in recent decades. But James Flynn has pointed out that there was a steady growth of IQ scores among Dutch people between 1952 and 1982, even though those taking the test around 1962 should have suffered from worsened nutrition as children during World War II (there was a Dutch famine in 1944). Also, there is little evidence that very many US children suffered from malnutrition between 1940 and 1970. So it's not like we can say, “Only in recent decades have American children started to eat properly.”

People trying to account for the Flynn effect usually consider only the period from 1930 onward. But the apparent increase in human intelligence since 1930 may be only one facet of a larger mystery of unaccountable increases in human intelligence, a mystery that may stretch back many thousands of years.

Consider the blossoming of human intelligence that occurred long ago. Rather suddenly, humans started to grow crops, and not too long after that, humans started to create cities. Before long we had things such as the glories of Greek sculpture, the philosophy of Plato, the mathematical works of Euclid, and the architectural and organizational achievements of the Roman Empire. But we cannot explain the intelligence behind such things by using natural selection as an explanation. As Alfred Russel Wallace (the co-founder of the theory of natural selection) pointed out in the nineteenth century, natural selection can only explain features that are needed for an organism to survive in the wild.

So we have a general mystery that exceeds the mystery of the Flynn effect. The mystery is: why has human intelligence increased at various times in ways we cannot explain?

I will now suggest a highly unconventional hypothesis to explain the Flynn effect. The Flynn effect may be evidence that human intelligence is being gradually increased by some external reality that is a partial or major source of human consciousness. Such a reality may be gradually increasing human intelligence to help us cope with an increasingly complex world, or to help us fulfill some human destiny that requires greater human intelligence.

To understand this hypothesis, I must first explain what is meant by neural reductionism, and why there are strong reasons for rejecting this assumption. Neural reductionism is a theory of the mind and brain that you have probably heard advanced many times. It is the idea that mind or intelligence is purely a product of the brain. A neural reductionist believes that your brain generates your intelligence rather like your liver secretes bile.

But there are quite a few reasons for doubting this simple theory. One reason is that we cannot plausibly account for very long-term human memories through any neurological explanation, mainly because (as discussed here) very rapid molecular turnover in the brain should make the brain an unsuitable substrate for a 50-year storage of memories, or even a storage of memories lasting longer than two years. Another reason is that the physician John Lorber documented many cases of people who functioned well even though the great majority of their brains were destroyed by disease. Another reason is that neural reductionism cannot account for psychic phenomena such as near-death experiences, out-of-body experiences, and extra-sensory perception (the latter something very well-demonstrated in convincing laboratory experiments such as those done by Professor Joseph Rhine, which have never been successfully debunked).

Suppose we consider possibilities other than neural reductionism. It may be that our consciousness and intelligence comes largely or mainly from some mysterious external reality outside of our brains.

Let's imagine a 10-year-old child who enters some data into a smartphone. If you ask the child where that data is stored, the child will say something like: “Why in the smartphone, of course – where else could it be?” But depending on the smartphone app being used, the data may not be stored in the smartphone. It could be the app uses a wi-fi connection to connect to an external web server that connects to a relational database server which stores the data the child has entered into the smartphone. But the child knows nothing of such an unseen infrastructure, so of course when she is asked where her data is stored, she answers that it is in the smartphone. Similarly, our long-term memories and intelligence may depend on some mysterious consciousness and information storage infrastructure that is outside of our brains. But since a scientist knows nothing of such an infrastructure, when he is asked where our memories are stored, he answers: “In the brain, of course – where else could it be?”

And if the child uses her smartphone to do a math problem, and you ask her, “Where was the intelligence that helped you do that?” the child will answer, “In the smartphone, of course – where else could it be?” But the actual facility that helped her may be a remote Google server thousands of miles away. Similarly, if a scientist is asked where is the intelligence that led you to ponder some cosmic mystery, he will answer, “In the brain, of course --- where else could it be?” But our minds may depend on some mysterious intelligence infrastructure outside of our bodies.

Once we start thinking along these lines, that our intelligence may come partially or largely from some mysterious external reality outside of our brains, we have opened the door to a radical new hypothesis to explain the Flynn effect. The hypothesis is this: some external reality that is the source of our consciousness may be deliberately causing a gradual increase in human intelligence. This may be to help us cope with an increasingly complex world. Or it may be to help us fulfill some great destiny that is planned for humanity. The same reality may have increased human intelligence at the time when humans first started to build cities.

The idea that human intelligence is being gradually increased by some mysterious external power seems like a reasonable hypothesis. But there may be one thing that argues against the very idea that human intelligence is gradually increasing.

I refer, of course, to the inane drivel that is the 2016 American presidential campaign. 

Postscript: The average person probably has the idea that the human brain evolved until it was large enough to allow for thinking and spirituality, at which point human culture and religion first started to emerge. The link here reports "anatomically modern" human skull remains dated to 160,000 years ago, with what a scientist describes as "full-fledged Homo sapiens features."  But humans did not start engaging in symbolic behavior until about 80,000 years ago. How do we explain that? It's as if humans got some big intelligence boost 80,000 years after hominid brains reached their largest size. 

Our Feeble Minds

[Man] is very small, very simple, very little capable of insight.
His knowledge of the great orb of things is but a fledgling's knowledge.
His admiration is a nestling's admiration for the things kindly to his own small nature....The music of the spheres passes over him, through him, and is not heard.
Olaf Stapledon, Last and First Men

Let us consider the human brain. Should we give it high marks or low marks for its various abilities? Looking at the matter from an earthly perspective, it would seem that the human brain should be ranked very highly indeed. No other animal has nearly as much intelligence as a human being.

But when we look at the matter from a galactic or cosmic perspective, we may get a very different outlook on the human mind. Consider the question of galactic civilizations. A civilization on another planet could have arisen any time during the past billion years. Extraterrestrial species may have had millions of years to evolve intelligences vastly greater than ours. Minds on other planets may be as far above our minds as our minds are above the minds of our dogs or our goldfish.

Having looked at the matter from such a perspective, we are ready to take a fresh look at the different mental abilities of our minds. Like an elementary school teacher, let us grade each of these abilities on a scale of A to F. We will use a scale in which A is the highest ability we can reasonably imagine for an intelligent creature in the universe, and F is basically a complete lack of a particular ability.

Memory: Humans have two types of memory: short-term memory and long-term memory. Our short-term memory is very weak, with only about the capacity of a few index cards. Give someone ten minutes to memorize a page of 40 names, and he will be very unlikely to do it. Our long-term memory is much better, but still extremely limited. A laptop or I-Pad with the right software can do a much better job at recalling the cities of the world (or the thousand most important events of world history) then a human will ever do. Our long-term memories are also subject to decay and degradation. We sometimes create memories of things that did not actually occur, a process called confabulation. Another weakness of our memory is how slow it takes for facts to transfer into our memory. It is as if there is a bottleneck which prevents us from ever memorizing more than a small number of facts on any particular day.

Grade: D+.

Numerical Ability: The human mind is very poor with numbers. There are watch-sized calculators that can do multiplication and division hundreds of times faster than almost any human. We have a hard time even remembering numbers. The average person can't remember the phone number he was using before his current phone number. We also have a hard time understanding principles that involve numbers. Consider a principle such as the law of large numbers, which effectively means that in general the longer you spend gambling at a casino on any particular day, the higher the likelihood that you will go home with less money than you had when you came in. Most people have difficulty understanding that principle, which is one reason casinos make so much money. There are numerous other cases in which people act as if they had a poor understanding of probability rules.

Grade: D-

Language Ability: This is the one area where the human brain gets a grade higher than D. When humans are very young, they have a remarkable ability to learn new languages. However, the ability quickly fades, and by the time someone gets to be a college student, it becomes very difficult to learn new languages.

A grade of C- seems fair, because it is easy to imagine more intelligent beings that could learn a new language in only a few weeks.

Grade: C-

Multitasking: Many people think they're good at multitasking, meaning doing multiple things at the same time. But that's actually a misconception. When people think that they're multitasking, they're almost always just rapidly switching back and forth between different tasks. You may think that you are doing your homework and checking Facebook at the same time, but at any one time you are actually concentrating on one of these things or the other. "People can't multitask very well, and when people say they can, they're deluding themselves," said neuroscientist Earl Miller in this NPR piece entitled “Think You're Multitasking? Think again.”

But for years computers have had a real ability to multitask. On any dual-processor laptop you can run one program that performs 3D graphics calculations while another program does financial calculations, with each running full-blast.

It is easy to imagine extraterrestrial minds which might have a true multitasking ability. For example, an extraterrestrial might be able to read a book at the same time as he writes an analysis of what he was reading, going full blast at both activities at the same time.

Grade: F

Imagination: Humans have a limited amount of imagination which sometimes leads to works of arts such as novels or screenplays. But our imagination is weak. To even imagine in depth a world a little different from our own usually takes a writer weeks or months of laborious effort. It is almost impossible for us to imagine some reality very different from any reality that we have previously learned about or read about or seen depicted in a movie. For example, try to imagine in depth a civilization a hundred times older than our civilization, in which everybody is a hundred times smarter than any of us. Such a thing is pretty much impossible. We don't even have a very good ability to imagine what it would be like to be someone living in a different country on our planet, following a different religion. If we were better at such a task, there would not have been so much bloodshed in wars, because we would find it much easier to empathize with the people we are fighting.

Grade: D+

Insight: One example of insight is the ability to deduce an underlying truth or pattern from a large set of observations Another example of insight is to deduce a possible method of solving a problem. Humans do not have very much in the way of insight. Ask yourself – when was the last time you had a discerning insight about yourself or about life or about mankind? For humans, discerning insights are few and far between. When we look out at the vast universe beyond our little planet, our insight fails us, and we come up blank. But it is easy to imagine a superior mind who might have dozens of brilliant insights every day.

Grade: D

Reasoning: Humans are capable of doing an abundance of reasoning. But our reasoning is all too often riddled with fallacies. We fall for the same old logical fallacies again and again. Moreover, when we should be logically reasoning in a dispassionate and objective manner, we let all kinds of subjective thinking and emotions and prejudices and wishful thinking enter our minds, causing us to reach invalid conclusions and make inappropriate assumptions. We should put our emotions and hopes and hatreds and fears in the closet while we reason, but instead we let these things rule our minds while we reason.

Grade: D

So there is a report card on that weak, feeble thing known as the human mind. We have no real insight into how weak our brains are, because we lack the mental ability to vividly imagine a state of mind far surpassing our intelligence. We are like those born blind, who never fully understand what they are missing. Perhaps a better analogy is this: we are like those born blind on a planet in which everyone is blind, and no one realizes what they are missing.