Black Lozenge

“For to the one who has, more will be given, and from the one who has not, even what he has will be taken away.”

Mark 4:25 ESV

Common Knowledge?

There are theories of intelligence that go something like this:

The world is not limited by IQ. We are all limited by bravery and creativity.

Astro Teller

The winner’s edge is not in a gifted birth, a high IQ, or in talent. The winner’s edge is all in the attitude, not aptitude. Attitude is the criterion for success.

Denis Waitley

If only these optimistic thoughts and theories were true.

For any given adult, isn’t their IQ something they worked for?

While it is optimistic to believe that IQ is something purely (or even majority) environmental, the vast amount of literature on IQ has shown that intelligence is mainly from your genes.

We can infer from twin studies that the high general heritability rate of IQ is around 70-80% – possibly higher.

To conduct a study, one might take two twins separated at birth (in which they have a different environment) and measure how close of an IQ they have with each other.

But aren’t the environments in which the twins separate to of similar nature?

Definitely not as much as one might think. McGue (2007) took adoptive and non-adoptive families to compare the environmental dimensions. Relative to non-adoptive families, adoptive families experienced a 41% reduction of variance in parent disinhibitory psychopathology and an 18% reduction of variance in socioeconomic status (SES). There was limited evidence for range restriction in exposure to bad peer models, parent depression, or family climate. However, restriction in range in parent disinhibitory psychopathology and family SES had no effect on adoptive-sibling correlations for delinquency, drug use, and IQ.

These data support the use of adoption studies to obtain direct estimates of the importance of shared environmental effects on psychological development.

McGue (2007)

Isn’t a child’s IQ dependent on how they were raised and not their biology?

There’s multiple scientific ways in which we can go about this question.

If our intelligence is based on our upbringing in our environments, fraternal twins raised under the same roof should have a smaller IQ disparity on average than identical twins separated at birth.

However, this doesn’t appear to be true.

Hunt (2011)

Identical twins who were not raised in the same household show higher similarities in IQ than fraternal twins who were raised in the same household. While there is obviously some environmental factors, for the most part, intelligence is better predicted by biology than environment.

It is also interesting that twin studies could actually under predict IQ heritability. Single pass (short and long term)

The Wilson Effect

During a child’s development is actually a time in which IQ can increase or decrease depending on the environment. However, a phenomenon known as regression towards the mean shows that a child’s intelligence slowly starts resembling its biological parents. We can see this phenomenon by looking at studies of children who take cognitive ability tests over the span of their adolescence. Interestingly enough, the heritability of general cognitive ability increases linearly from childhood to young adulthood.

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Increasing heritability and decreasing shared environment for general cognitive ability from childhood to adolescence to young adulthood. Lines show additive genetic (A), common environment (C) and non-shared environment (E) estimates from childhood to young adulthood.  (Source)

The Louisville Twin Study includes nearly 500 pairs of twins and their siblings who have participated in a longitudinal study of mental development, beginning in infancy and extending to adolescence. The results show heritability and genetic influence of intelligence increases with age.

Wilson (1983)

Finally, Bouchard (2013) documented the Wilson effect diagrammatically with key twin and adoption studies, including twins reared apart, that have been carried out at various ages and in a large number of different settings. The results show that the heritability of IQ reaches an asymptote at about 0.80 at 18-20 years of age and continuing at that level well into adulthood. In the aggregate, the studies also confirm that shared environmental influence decreases across age, approximating about 0.10 at 18-20 years of age and continuing at that level into adulthood. These conclusions apply to the Westernized industrial democracies in which most of the studies have been carried out.

FIGURE 2 Estimates of genetic and shared environmental influence on g by age. The age scale is not linear (see text for details).

Bouchard, T. (2013). The Wilson Effect: The Increase in Heritability of IQ With Age. Twin Research and Human Genetics, 16(5), 923-930. doi:10.1017/thg.2013.54

Can’t we just put kids in better family structures?

Unfortunately, family and parenting characteristics are not significant contributors to variation in IQ scores. Virtually, the only way that the environment can affect IQ is negatively

Aren’t there multiple types of intelligence anyway?

Yes, but all of the “multiplicities” of cognitive intelligence correlate heavily to the g factor, or general intelligence.

The practical validity of g as a predictor of educational, economic, and social outcomes is more far-ranging and universal than that of any other known psychological variable.

Isn’t there cultural bias in IQ tests?

A popular critique to IQ tests is that they have a cultural bias against ethnic minorities. However, this is not the case. There is a scientific consensus that “cultural bias” has no effect on measured intelligence. Blacks aren’t affected by this cultural bias. The National Research Council and The National Academy of Sciences conducted an investigation of bias in mental testing, and concluded that cultural bias had virtually no factor in determining IQ scores.

Its also interesting to note that East Asians have an extremely different culture than the west but consistently score higher on IQ tests than westerners and furthermore IQ tests in high school slightly overpredict black and hispanic GPA.

Is IQ even that important?

Normality and Occupational Success

Richard J. Herrnstein and Charles Murray, authors of The Bell Curve, devised a Middle Class Values Index that ranks a person’s likelihood of having a stereotypical middle class life, such as:

graduating from high school, not being incarcerated, being married to one’s first spouse, being in the labor force (for men), and not having a child out of wedlock (for women).

The lower the IQ, the less likely someone is to live such values:

  • 16 percent for IQs under 75 IQ;
  • 30 percent for IQs from 75-90;
  • 50 percent for IQs 90-100;
  • 67 percent for IQs 110-125; and
  • 74 percent for IQs above 125 have these middle-class values.

Low IQ individuals may find it difficult to perform well in very complex or fluid jobs (such as management in an ambiguous, changing, unpredictable fields). However, an individual with an IQ over 115 have no restrictions on which job they can do.

Interestingly, age, interest, education, parental income were not as predictive to job success than IQ. Almost every study has placed IQ as the highest predictor in job success.

In fact, there is evidence that a nation’s IQ correlates to how wealthy that country is.


There is a large body of research which indicates that IQ negatively correlates to criminality


In fact, national IQ negatively correlates to national levels of criminality.

IQ a national crime.jpg

Finally, while many say the criminal justice system is racist, when factored for personal history and IQ, any and all racial disparities vanish.

Creativity and Sociability

Contrary to popular belief, high IQ individuals aren’t the stereotypical “nerds” that some might believe. High IQ individuals tend to be more creative and sociable and confident.

People with higher IQs even tend to live longer and healthier

Is it malleable?

While there may be small changes to a child’s IQ early on, there is still strong genetic correlation, eventually a person’s IQ will shift towards their genes eventually.

What’s so wrong with a a low IQ?


Many may be familiar with Jordan Peterson’s IQ concern with the military, here is a breakdown of his concern.

10 U.S. Code § 520 – Limitation on enlistment and induction of persons whose score on the Armed Forces Qualification Test is below a prescribed level

(a) The number of persons originally enlisted or inducted to serve on active duty (other than active duty for training) in any armed force during any fiscal year whose score on the Armed Forces Qualification Test is at or above the tenth percentile and below the thirty-first percentile may not exceed 20 percent of the total number of persons originally enlisted or inducted to serve on active duty (other than active duty for training) in such armed force during such fiscal year.

The Armed Forces Qualification Test is applied as sections of the ASVAB, and the score represents an applicants percentile ranking in the general population. The 31st percentile represents an IQ of approximately 93; the 10th percentile represents an IQ of 81 meaning that the law dictates a preference for IQ’s above 93, and a prohibition on IQ’s below 81.

This is interesting as the military is desperate for people to join. The military has spent half a billion dollars just on advertising. If you ask anyone who served in this generation, they will say how willing to lie military recruiters are just to get you to join because recruitment is a “numbers game”.

The truth is that the United States, despite wanting to grow the military, won’t allow individuals with IQs below 80 to serve in the military because they lack adequate trainability.

Furthermore, civilian employers likewise tend to avoid hiring them except for the simplest jobs. Low IQ individuals are at high risk for failure and generally require special circumstances in order to prosper socioeconomically. High-IQ individuals, on the other hand, seem to require unusual circumstances to fail.

Relation with the General Population

This means that 8.4% of the population (1 in 12 people) have an IQ of 79 or lower which is borderline retarded and that the government would pass laws to not allow them to join the military

It is also concerning that IQ is may be plateauing or even dropping.

The Pareto Principle

The Pareto Principle refers to the 80/20 rule in which roughly 80% of effects come from 20% of the cause(s).

Image result for pareto principle


  • 80 percent of the errors and crashes in Windows and Office are caused by 20 percent of the entire pool of bugs detected
  • 20% of the exercises and habits have 80% of the impact
  • 20% of patients have been found to use 80% of health care resources
  • 80% of crimes are committed by 20% of criminals

Free Markets and Concentration of Wealth

Distribution of world GDP, 1989 shows that top 20% pay for all revenue for the government is doing this.

The problem with this is that 20% are super highly correlated to being rich and successful. A bigger problem is that those who are envious of one who has much can not change themselves to a high enough degree.


While an uncomfortable subject, IQ may be the most important predictor of an individuals success and if we ignore it and refuse to acknowledge it, the gap may be filled with something even less appealing.

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