The introduction defines this book as an attempt to close the gap between popular notions about Intelligence, which is often not supported by scientific research, and expert opinion based on such research. To make things clear, the author provides the definition of Intelligence generally supported by a consensus of scientists:
Intelligence is a very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly and learn from experience. It is not merely book learning, a narrow academic skill, or test-taking smarts. Rather, it reflects a broader and deeper capability for comprehending our surroundings – “catching on,” “making sense” of things, or “figuring out” what to do. (Gottfredson, 1997a, p. 13)
The author also provides here samples of IQ test questions, some minimally required statistical concepts, and a bit of history. Below is a general overview of the presented ideas and data.
Section 1 The Nature of Intelligence
Intelligence Is Whatever Collection of Tasks a Psychologist Puts on a Test
FALSE – all cognitive tasks measure Intelligence in one way or another, which allows using factor analysis to arrive at a consistent g factor.
Intelligence Is Too Complex to Summarize with One Number
FALSE – Since all cognitive tasks are highly correlated, it is possible to derive a common factor that predicts performance on the wide variety of such tasks
IQ Does Not Correspond to Brain Anatomy or Functioning
FALSE – The correlation is well established, but only at a high level. The details would require massive research effort.
Intelligence Is a Western Concept that Does Not Apply to Non-Western Cultures
FALSE – g factor equally strong in Western and non-Western people, the cultural differences notwithstanding.
There Are Multiple Intelligences in the Human Mind
There is no empirical confirmation that there are independent levels of Intelligence in different functional areas of human activities.
Practical Intelligence Is a Real Ability, Separate from General Intelligence
Attempts to identify some practical intelligence areas independent from g were not successful. However, some non-cognitive human traits impact practical abilities that define the success or failure of an effort.
Section 2 Measuring Intelligence
Measuring Intelligence Is Difficult
FALSE – Intelligence is relatively easy to measure, and practically any cognitive task does it to some extent. Different knowledge bases and experiences do not relate to IQ tests designed to neutralize differences in backgrounds.
The Content of Intelligence Tests Is Trivial and Cannot Measure Intelligence
FALSE – the simple measurement can easily produce a reasonable estimate of a complex phenomenon. The author provides an analogy with a simple thermometer measuring the complex heat process.
Intelligence Tests Are Imperfect and Cannot Be Used or Trusted
The “imperfect” part is TRUE, but the results are good enough to be used and trusted, as confirmed by empirical data.
Intelligence Tests Are Biased against Diverse Populations
FALSE – professionally developed tests show consistent results unbiased by race and other irrelevant factors. The author provides an interesting description of the process in Ellis Island that pretty much demonstrated the validity of tests.
Section 3 Influences on Intelligence
IQ Only Reflects a Person’s Socioeconomic Status
The “ONLY” part is FALSE because genetics play an essential role: generally, about 50%. However, research demonstrated that adopted children do have higher IQ and that children in educated households get to hear more words, spend more time with adults, have better food, and so on, which has at least some impact on IQ
High Heritability for Intelligence Means that Raising IQ Is Impossible
FALSE –the incidents with lead poisoning and other environmental factors demonstrate that they have a material impact on IQ.
Genes Are Not Important for Determining Intelligence
FALSE – genes are essential for everything from height to digestion to IQ. It is always a combination of nature and nurture.
Environmentally Driven Changes in IQ Mean that Intelligence Is Malleable
TRUE – as demonstrated by adoption studies, the Flynn effect, and individual fluctuation. Most of the improvements over time are at the population level, while IQ measure the variation within a population
Social Interventions Can Drastically Raise IQ
Extreme neglect drives IQ down, but all known interventions, especially highly tested preschool programs, demonstrated only temporary improvements that disappeared over time.
Brain-Training Programs Can Raise IQ
So far, no program has demonstrated a significant improvement. However, there is no proof that no program never will.
Improvability of IQ Means Intelligence Can Be Equalized
FALSE – it is a statistical impossibility since IQ measures variation, not an absolute value. Neither genetic nor environmental components could be feasibly equalized for everybody.
Section 4 Intelligence and Education
Every Child Is Gifted
FALSE – also a statistical impossibility because all children are different.
Effective Schools Can Make Every Child Academically Proficient
It depends on what is considered proficiency. The difference will remain, but some specific level could be achieved by everybody, providing it is low enough.
Non-cognitive Variables Have Powerful Effects on Academic Achievement
TRUE – no school grades based on IQ only, so lower IQ could be compensated by hard work and discipline, at least to some extent. Similarly, a high IQ would not help if one is lazy and undisciplined.
Admissions Tests Are a Barrier to College for Underrepresented Students
TRUE – they are, but eliminating them would not change the factual differences in IQ. All attempts to equalize failed and will always fail, but selection based on proportionality deprives the brightest of opportunities they could use to produce benefits for all. In contrast, force-feeding opportunities to less bright would only mean squandering these opportunities.
Section 5 Life Consequences of Intelligence
IQ Scores Only Measure How Good Someone Is at Taking Tests
Here is a lovely picture of correlations:
Intelligence Tests Are Designed to Create or Perpetuate a False Meritocracy
FALSE – Tests were designed to simplify the selection of people to do more or less complex tasks. Ideas of meritocracy and ideology around it came later.
Very High Intelligence Is Not More Beneficial than Moderately High Intelligence
Research does not support the idea of a threshold about which higher IQ does not matter. However, IQ always works in the mix with many other factors. Therefore, simplified correlation does not work either.
Emotional Intelligence Is a Real Ability that Is Helpful in Life
There is no evidence that EQ works or even exists, and multiple attempts to raise EQ failed to produce results.
Section 6 Demographic Group Differences
The author begins by presenting fundamental principles:
Males and Females Have the Same Distribution of IQ Scores
Here is the conclusion:” While males and females are equal in average Intelligence, the distribution of their abilities differs in other ways. However, in broad non-g cognitive abilities – like spatial ability, verbal reasoning, and mathematical reasoning – mean differences do exist. Females tend to score higher (on average) on verbal abilities, while males have higher average performance on spatial ability and mathematical reasoning. Across these abilities, though, the differences average out to produce equal means on overall IQ. An important difference exists in variability in cognitive abilities. Males have a standard deviation that is 5–15% larger than the standard deviation for females. As a result, there is a greater percentage of males than females at the high and low extremes of most abilities.”
Racial/Ethnic Group IQ Differences Are Completely Environmental in Origin
The author provides a very detailed discussion well supported by statistical data but concludes that there are genetic differences even if everybody wants it not to be so. The author also discusses the inevitability of such differences due to the diverse evolutionary path of races.
Unique Influences Operate on One Group’s Intelligence Test Scores
Here the author discusses X-factor that supposedly generates differences between groups. Here is the definition:
The author reviews four different candidates to be X-factor and concludes that none of them meets the definition’s requirements.
Stereotype Threat Explains Score Gaps among Demographic Groups
The recently popular explanation of differences by the Stereotype Effect failed, mainly due to the replication crisis in psychology. The failure of confirmation does not mean proof of existence. It requires new research with a better methodology, including rigorous replication of results.
Section 7 Societal and Ethical Issues
Controversial or Unpopular Ideas Should Be Held to a Higher Standard of Evidence
The only criteria for science should be true or false, with ethical constraints necessary to prevent damage. Other than that, more knowledge is always better than less.
Past Controversies Taint Modern Research on Intelligence
This part is mainly about Eugenics, its popularity, and later disgrace due to its use by Nazis. Eugenics as an idea is mainly irrelevant by now, and it should not impact contemporary genetic research in any way.
Intelligence Research Leads to Negative Social Policies
Here the author provides some guidelines:
- First, do not promise more than a policy or program can deliver.
- Second, stick to facts – not wishful thinking. Many of the misconceptions that I deal with in this book are ideas that people want to believe.
- Third, do not ignore genetics. Nearly every trait or life outcome is partially influenced by genes
Intelligence Research Undermines the Fight against Inequality
The critical point here is that people are different but must be treated equally legally and ethically. The author also presents very interesting results that demonstrate how little IQ and other scores are relevant to actual live decision making:
- Randomly guessing which individual is more intelligent will be correct 50.0% of the time.
- Discriminating on the basis of race and assuming that the European American is always more intelligent results in a correct decision 76.0% of the time.
- Ignoring race and using IQ scores to identify which person is smarter increases decision accuracy to 94.2%.
- Using race and IQ scores to identify which person is smarter lowers the accuracy slightly to 94.0%.
In other words, ignoring race produces better decisions.
Everyone Is About as Smart as I Am
FALSE – people are different, and individuals with higher IQs are better at solving cognitive problems than people. The author calls for compassion and helps people with lower abilities rather than keeping them in contempt.
In conclusion, the author provides the summary of the book:
The author concludes by stressing the value of intelligence research and expresses hope that helps to promote a better comprehension of the world.
MY TAKE ON IT:
This book is an excellent collection of research results and presentations of the current level of knowledge about human Intelligence, its measurement, and relevant popular conceptions, some true and some false. I want to stress a few points related to these themes.
The first one is that everybody without exception should have not only compassion for others with lower IQ but also humility that is absolutely necessary if one thinks about the reality of the Bell Curve: if you are in the top 1%, it means that on this planet with about 8 billion people there are 80 million individuals more intelligent than you are. Or, if one goes local: 3.2 million people in the USA are also more intelligent than you are.
The second point is that it would be best to stop looking at IQ and another psychological testing as a tool to define a place in a hierarchy. The objective should not be selecting people for the slots higher or lower in the hierarchy. Instead, it should be the better understanding of self and adjusting your actions so that planned results are achievable and effective in producing the best quality of life one can have in the place and time of his/her/its existence.