If Humans and Chimps Are 15 Percent Genetically Different, What Difference Does That Make?

Think about how often you've heard it said that the genetic difference between human beings and chimpanzees is only slightly more than 1 percent, and therefore humans are 99 percent similar to chimps.  It is also said that this proves that chimps--and also bonobos--are our closest living evolutionary relatives.  This seems to be confirmed by the fact that chimpanzees and bonobos are more genetically similar to humans than to gorillas.  This 1 percent difference between humans and chimps fits the evolutionary timeline of five to eight million years since humans and chimps diverged from their last common ancestor.

But now an article published last May in Nature (Yoo et al., 2025) reports that a complete sequencing of ape genomes shows that the genetic difference between humans and chimps is a lot greater than 1 percent--more like 15 percent!  And yet perhaps I shouldn't say this article "reports" this because if you read the main article, you won't see this claim of a 15 percent difference.  You have to go to the Nature website and print out the "Supplementary Data" for the article, and even then, you have to work through the technical jargon to find the 15 percent difference.  Casey Luskin has posted a helpful article at the Discovery Institute website that digs deep into the "Supplementary Data" to uncover this remarkable finding.  You would think that such a surprising discovery would be prominently announced in Nature and in press releases: "The Chimp-Human Genetic Difference Is Not 1% But 15%!"  I think Luskin is right to suggest that the editors at Nature must have worked hard to hide this finding because it refutes the popular claim about "only a 1% difference" separating humans and chimps.  

Luskin says this refutes one of the "icons of evolution," as Jonathan Wells called them--that is, widely believed assertions about evolution that the proponents of "intelligent design theory" and "young-Earth creationism" deny.  It's not surprising, therefore, that creationists like Ken Ham have cited Luskin's article as proving that the creationists are right to deny that there is any common evolutionary ancestry linking humans and apes.  Ham explains that Bible teaches us that God created the "ape kind" and the "humankind" separately and created humans as a unique kind made in the image of God.

And yet I don't see that this newly discovered "15% difference" provides any support for the intelligent design theorists or the creationists in their denial of evolutionary science.

But first we need to understand how this new research allows us to calculate genetic difference and similarity.  The title of the article in Nature is "Complete Sequency of Ape Genomes."  The emphasis is on "complete," because the first human and ape genome sequences were incomplete.  They excluded extremely repetitive sequences and large-scale structural differences such as inversions and duplications of genomic sequences.  So the first reports of only 1% differences between human and chimp genomes were based on incomplete drafts of the genomes.  But now the complete sequency in this article allows for a fuller comparison of similarities and differences in the sequences.

The authors found two kinds of differences--"gap divergence" and "single nucleotide variation" (SNV).

Luskin prepared this figure to illustrate the difference between "SNVs" and "Gaps" between two genomes.  Gaps represent nucleotides or segments of nucleotides that don't exist in one of the genomes.  SNVs represent places where the nucleotides are different for the two genomes.  In this illustration, we have 30 nucleotides of the target genome with 3 SNVs and 9 gaps relative to the query genome.  So SNV divergence is 10%, and gap divergence is 30%, which means a total divergence of 40%.

If you go to the Supplemental Data for the Yoo et al. article, you will see that Figure III.12 shows the SNVs in comparing the genomes for humans, chimpanzees, bonobos, and orangutans--the four "great ape" species who belong to the Hominidae family.  When the human genome is the "target" genome, the "gap divergence" for the gorilla genome is 27.3 percent, for the Sumatran orangutan it's 16.5 percent, for the bonobo it's 14.4 percent, and for the chimpanzee it's 13.3 percent. 

Figure III.11 shows the SNV divergences, which are 2 percent for the gorilla, 3.6 percent for the Sumatran orangutan, 1.6 percent for the bonobo, and 1.6 percent for the chimpanzee.

If we add the gap divergences to the SNV differences, we get these total degrees of difference between human and ape genomes: 29.3 percent for the gorilla, 20.1 percent for the Sumatran orangutan, 16 percent for the bonobo, and 14.9 percent for the chimpanzee.  That's how we get the estimate of almost 15 percent difference between the chimp and human genomes, which is a lot higher than the purported 1 percent difference.  

It should be noted that these comparisons are for the 44 non-sex chromosomes in the human genome--that is, excluding the X and Y chromosomes.  As compared with chimps, the human X chromosome has a 4.4 percent gap divergence and 1.1 percent SNV divergence, while the human Y chromosome has an amazing 56.6 percent gap divergence and 3.9 percent SNV divergence.

Although this new research shows that the genetic differences between humans and apes are greater than had been previously reported, this does not deny the evolutionary story of the common evolutionary ancestry of humans and apes.  The genetic similarity between humans and apes is still very great--85 percent!  And humans are more genetically similar to chimps and bonobos than they are to orangutans and gorillas, which supports the claim that chimps and bonobos really are our closest living evolutionary relatives.

ALL IN THE GENES?  OR FOUR DIMENSIONS OF EVOLUTION?

There is an obvious problem here, however.  All of us have seen chimpanzees in zoos.  And many of us have seen bonobos if we have gone to zoos in San Diego, Milwaukee, or Cincinnati that have bonobos.  Those zoos often have displays that say something about the 1 percent difference between humans and chimpanzees.  Now those displays might have to be changed to read 15 percent.  But even so, when we look at those apes and compare them with humans, it's very hard to believe that the difference is only 1 to 15 percent.  It's simply not true that humans and apes are 85 percent the same.  The gap between the mental achievements of human beings and those of the apes is staggering.

Most human beings don't believe that evolutionary genetics can fully explain that gap, and that's why so many people reject the science of evolution, and why so many believe that the superiority of the human mind over the ape mind can only be explained by the supernatural work of an Intelligent Designer or Divine Creator.

They are right to believe that evolutionary genetics cannot fully explain the achievements of the human mind.  But that's because genetics is only a small part of evolutionary science.  As I have indicated in some previous posts, there are four levels of evolutionary inheritance--genetics, epigenetics, culture, and symbolism (Jablonka and Lamb, 2005).

The genetic inheritance system is the foundation for the Neo-Darwinian theory of evolution. But genetic reductionism and determinism fail to see how gene action depends on the complexity of interacting causes within the genome, within cells, within organisms, within groups of organisms, and within ecological circumstances. Except for a few single-gene genetic disorders, "genetic astrology"--the idea that genes directly control specific traits--must be dismissed as foolish.

The epigenetic inheritance system is evident in the differences between specialized cells. Brain cells, liver cells, and skin cells are very different, although the nucleus of each cell has the same genome. Their differences are epigenetic, rather than genetic, because they have arisen through their developmental history in which there were different patterns of gene activation and interaction within the cell. This developmental information is passed on as these cells divide to produce more cells of the same kind. It is possible for evolution to occur through heritable epigenetic variation even without genetic variation. Just as a musical recording transmits interpretations in musical performances of a musical score, so does an epigenetic inheritance system transmit interpretations of the information in DNA, so that there is a Lamarkian inheritance of phenotypes instead of genotypes. One version of such inheritance that is now under active study is DNA methylation: strands of DNA are chemically modified during development, and these modifications can be transmitted through reproduction.  The chemical modification in epimutation is not in the DNA itself but in the chromatin marking. Methylated DNA has a small methyl group attached to some of its bases. The pattern of methylation influences which regions of DNA are expressed. The different kinds of cells in the human body have the same DNA, but the different patterns of methylation regulate the expression of DNA.

The behavioral inheritance system is the transmission of information among animals through social learning. For example, among some animals (including human beings) mothers transmit food preferences to their offspring, because information about what mother is eating is transmitted either in the womb or through suckling, so that the offspring inherits a preference for that food. More complex forms of social learning come through animal culture. For example, some chimpanzees can discover how to open nuts with a stone and then pass on this practice within their group so that it becomes a social tradition. Different communities of chimps in Africa have different cultures based on distinctive profiles of traditional practices transmitted by social learning. As opposed to genetic evolution, cultural evolution is not blind but targeted to functional change.

The symbolic inheritance system is uniquely human because it shows the qualitative leap that defines our humanity as based on our capacity for symbolic thought and communication. Other animals can communicate through signs. But only human beings can communicate through symbols. The evolution of human language was probably crucial for the evolution of symbolism. Symbolic systems allow us to think about abstractions that have little to do with concrete, immediate experiences. Symbolic systems allow human beings to construct a shared imagined reality. These symbolic constructions are often fictional and future-oriented. Art, religion, science, and philosophy are all manifestations of human symbolic evolution. 

To explain why humans are somewhat similar to the great apes and yet radically different from them, we have understand how all four levels of human evolution have shaped human beings to be the unique animals that they are.

COMMON DESCENT OR INTELLIGENT DESIGN?  OR BOTH?

Although Casey Luskin is an advocate of intelligent design theory as the best alternative to evolutionary science, he stresses that he is not pointing to the new estimate of 15 percent difference between humans and chimps as evidence that refutes evolution.  As long as the five to eight million years since humans and chimps diverged from their last common ancestor is enough time for this 15 percent difference to evolve, then the evolutionary story of common ancestry is still defensible.  

But still, Luskin suggests, intelligent design theory has a better explanation for this genetic similarity--85 percent--between chimps and humans:  "Functional genetic similarities between humans and chimps could be explained by common ancestry or by common design.  Common ancestry is not the only way to explain genetic similarities.  Intelligent agents can re-use functional code in different designs.  Common design can explain shared functional genetic similarities just as well as common descent can."

There are two mistakes in Luskin's reasoning, however.  First, he mistakenly assumes a dichotomy between common descent and common design, as if they were mutually exclusive.  As I have noted previously, one of the leading advocates of intelligent design theory--Michael Behe--argues (in The Edge of Evolution) that the genetic similarity between humans and chimps is evidence that human beings evolved from primate ancestors shared with chimpanzees.  He explains that intelligent design is required to explain the emergence of the higher taxonomic levels of life (kingdoms, phyla, classes) but not the lower levels (orders, families, genera, species).  This means that the evolution of species could be fully Darwinian.

Behe is an intelligent-design evolutionist, because he insists: "The possibility of intelligent design is quite compatible with common descent, which some religious people disdain.  What's more, although some religious thinkers envision active, continuing intervention in nature, intelligent design is quite compatible with the view that the universe operates by unbroken natural law, with the design of life perhaps packed into its initial set-up" (166).  Luskin refuses to recognize Behe's position.

Luskin is also mistaken, however, in assuming the plausibility of the arguments for intelligent design.  He thus ignores my objection that the arguments for intelligent design are fallacious in two respects.  First, intelligent design reasoning depends completely on the fallacy of negative argumentation from ignorance, in which intelligent design proponents argue that if evolutionary scientists cannot fully explain the step-by-step evolutionary process by which complex living forms arise, then this proves that these complex forms of life must be caused by the intelligent designer.  This is purely negative reasoning because the proponents of intelligent design can offer no positive explanation of their own as to exactly when, where, and how the intelligent designer caused these forms of life.  

The second fallacy is the subtle use of the fallacy of equivocation--in the equivocation between human intelligent design and supernatural intelligent design.  We have all had the experience of seeing how human intelligent agents create artificial products by intelligent design.  But it does not follow logically from this that we have all had the experience of seeing how supernatural intelligent agents create artificial products by intelligent design.

CREATED BY GOD IN HIS IMAGE?  OR EVOLVED IN THE IMAGE OF PRIMATES?  OR BOTH?

Ken Ham (2025) argues, on the contrary, that even if we have not seen with our own eyes God creating everything out of nothing, this has been revealed to us through the Bible; and part of that revelation is that God created all the "kinds" of plants and animals separately, and He created the "chimp kind" to be utterly different from the "humankind," which was created in His image.

But as I have said in my previous posts on Ham and his two museums in Kentucky--the Creation Museum and the Ark Encounter--he mistakenly assumes that he is conveying the clear meaning of the Bible and that the Bible's clear teaching is incompatible with Darwinian evolution.

The Bible says nothing about God creating apes and humans as separate "kinds."  The Book of Genesis never mentions apes.  Actually, in the whole Bible, the Hebrew word for "ape" appears only twice (I Kings 10:22, 2 Chronicles 9:21), and never in the context of creation.  And while Genesis speaks of God creating plants and animals "after their kind," it never identifies human beings as a "kind."  Consider Genesis 1:26--"And God said, Let us make man in our image, after our likeness."  The phrase "after our likeness" takes the place of "after their kind," suggesting that in being created in the likeness of God, man is not bound by a "kind."  So there is no Biblical basis for Ham to speak of "humankind."

Moreover, the Hebrew word min that is translated as kind in the King James Bible is ambiguous.  In the Latin translation of the Bible, min is translated as the Latin word species.  Consequently, for almost two thousand years, Biblical believers assumed that God's creating "kinds" meant that God created each "species" separately, and that each species was eternally fixed.  But then after Darwin published his Origin of Species in 1859, in which he argued against the "theory of special creation" that God had created each species separating, some Christians began to believe that the created "kinds" in the Bible referred not to "species" but to some higher level of taxonomy.  Then, in 1941, the Christian biologist Frank Marsh coined the word baramin (combining the Hebrew words for "created" and "kind") as the best term for "created kind."  He argued that a "created kind" was not at the taxonomic level of "species" but at or near the level of "family."  This allowed Biblical believers to accept Darwin's theory of the origin of "species" by natural selection while also believing that God had created the "families" of plants and animals to be fixed and separate.  So, for example, we could say that God originally created the "family" of the finches, but within the limits of that "family," the separate species of finches endemic to the Galapagos Islands evolved by natural selection to be adaptive to those islands.

Notice what this means for the taxonomic classification of human beings.  If the "kind" of human beings refers to their taxonomic "family," then in modern taxonomy, human beings belong to the "family" of Hominidae, which includes chimps, bonobos, gorillas, and orangutan.  Even the young-earth creationist Todd Wood (2010) accepts this Hominidae classification of humans with the great apes, although he identifies the "human holobaramin" as the genus Homo.

This idea of "created kinds" was crucial for Ham in solving an old problem with Noah's Ark.  If the Ark carried all the "kinds" of land-based plants and animals, how could the Ark be big enough to hold all of the land-based species--which could be numbered in the millions?

Ham's creationist researchers have solved this problem by calculating that among these land-dependent vertebrate species, there are fewer than 1,400 known living and extinct kinds (that is, families).  This allows them to estimate that Noah had to have fewer than 6,744 individual animals on the Ark.  Once these animals left the Ark, speciation by natural selection within kinds could create all the living and extinct species that we know today.  The Ham's Ark Encounter is designed to show how as many as 6,744 animals and 8 human beings (Noah and his extended family) could survive on the Ark for almost a year.  But notice that this is a speculative reading of the Bible that never defines "kind" in this way.  This is not the clear meaning of the Bible, as Ham claims.  Indeed, if you go to the Ark Encounter in Kentucky, you might notice one display that speaks of the need for "Arktistic license" in making up details in the story of the Ark that have no basis in the Bible.

Since the Bible is so obscure in its creation story, and since so much of that story sounds like a figurative folk tale that was not meant to be a literal account of natural history, many Christians (like C. S. Lewis, Francis Collins, and Deborah Haarsma) have decided that the Bible could be read as allowing for theistic evolution or evolutionary creation.  According to this conception, God created the universal laws of nature at the beginning of the Universe, but then He allowed all the forms of life to emerge by natural evolution.  God is the "primary cause" of everything.  But the evolutionary process unfolds through the "secondary causes" of nature.  Even Darwin himself accepted this metaphysical conception of "dual causality" that reconciles belief in God as First Cause with acceptance of evolutionary science.  At various points in the Creation Museum and the Ark Encounter, there are displays that acknowledge that many if not most Christians accept some version of this theistic evolution.

But what about the creation of human beings in the image of God?  If the "image of God" refers to the God-like intellect of man, then we might argue that the extraordinary mental capacities of human beings could have evolved through the evolution of the primate brain.  I have argued that the evolution in the size and complexity of the primate brain passed over a critical threshold so that now there are 86 billion neurons in the human brain, and of that total, 16 billion are in the cerebral cortex, which includes 1.3 billion neurons in the prefrontal cortex.  That emergent evolution of the brain created the uniquely powerful human mind.  We were created in the image of the primate brain.

Even if we are only 15 percent genetically different from chimps, we are different in kind from chimps because we have the mental capacities for language, morality, and symbolic abstraction that they do not have at all.  That's the difference that makes all the difference.

REFERENCES

Behe, Michael. 2007. The Edge of Evolution: The Search for the  Limits of Darwinism. New York: The Free Press.

Ham, Ken. 2025. "Study Finds Chimp DNA Is Not '99% Identical' to Ours." Answers in Genesis. Ken Ham Blog. May 27. Online.

Jablonka, Eva, and Marion J. Lamb. 2014. Evolution in Four Dimensions: Genetic, Epigenetic, Behavioral, and Symbolic Variation in the History of Life. Revised edition. Cambridge: MIT Press.

Luskin, Casey. 2025. "Fact Check: New 'Complete' Chimp Genome Shows 14.9 Percent Difference from Human Genome." Science and Culture Today, May 21, online.

Wood, Todd Charles. 2010. "Baraminological Analysis Places Homo habilis, Homo rudolfensis, and Australopithecus sediba in the Human Holobaramin." Answers Research Journal 3: 71-90.

Yoo, Dong Ahn, et al. 2025. "Complete Sequencing of Ape Genomes." Nature 641: 401-418.

The History of Migration With Interbreeding: The Evolutionary Strategy That Made Us Human

I have argued for an "open borders" policy that would respect the natural human propensities to migration and interbreeding as shaped by the evolutionary history that has made us human.  In support of that argument, I now offer a brief genetic and cultural history of migration as a "melting pot of ideas, technology, and DNA" (Garcia-Bertrand and Herrera, 2018, p. 113; Goldin, 2024; Reich, 2018).

330,000-50,000 years ago.  Our earliest human ancestors emerged for the first time in Africa.  The oldest fossils with features shared with anatomically modern humans have been found in Jebel Irhoud, Morocco, dating to around 330,000-300,000 years ago.  Since other hominid fossils are scattered across most of Africa except for the Sahara Desert region, that suggests that the first human beings migrated long distances within Africa as they adapted to diverse ecological and climatic conditions.  As I have indicated previously, there is also evidence for extensive long-distance trade in Africa as early as 300,000 years ago.  So human evolution in Africa was shaped by both migration and trade.

Many Biblical believers--Jews, Christians, and Muslims--doubt this Darwinian account of the evolutionary origin of human beings because they believe it contradicts the Biblical teaching that God created Adam and Eve as the first human beings.  But the theistic evolutionists argue that there is no contradiction if one sees that God could have employed the natural evolutionary process to carry out His plan for the creation of human beings.

After all, even Darwin himself recognized that the religious appeal to God as the uncaused cause of nature cannot be refuted by reason.  All natural explanations of the world--including Darwinian science--must assume that ultimately the order of nature is the unexplained ground of all explanation. But there is no way by rational proof to deny the possibility that nature itself is the contingent product of nature's God.  Darwin recognized this in adopting the principle of dual causality, which originated in medieval Islamic and Christian theology.  He spoke of the laws of nature as manifested in evolution as "secondary causes," which left open the possibility of God's creative power acting through "primary causes" to create the original order of nature itself.  Darwin thus allowed for theistic evolution, which has been adopted by a long line of Christian thinkers, including C. S. Lewis, Francis Collins, and Alvin Plantinga. 

After the Genesis Flood, Noah and his family were the only human survivors left to populate the Earth.  Noah had three sons--Shem, Ham, and Japheth--"and from them came the people who were scattered over the whole earth" (Genesis 9:19).  The Bible then gives an elaborate genealogical history of how the nations arose from the migration of the descendants of Noah's sons over the earth.  For two thousand years, Christian writers have tried to trace the origins of all nations back to Noah's sons.  The dominant tendency was to attribute the paternity of Europeans to the children of Japheth, that of Asians to Shem, and that of the Africans to Ham.  Since the descendants of Ham were mysteriously cursed to serve their cousins as slaves (Genesis 9:27), this was interpreted as God's justifying the enslavement of Africans and condemning interracial marriage (Goldenberg, 2003).  Thus, this divinely ordained story of origins explained both the genealogical unity of all human beings through ancestry traced back to Noah and their genealogical diversity through ancestry traced back to one of Noah's sons.

130,000-95,000 years ago.  During this period, some anatomically modern humans began to migrate out of Africa into the Near East, where they could have met Neanderthals who were migrating out of Europe.  Genetic analysis indicates that Neanderthals had separated from the human lineage 770,000-550,000 years ago.  Neanderthal skeletons and DNA show that the Neanderthal lineage was evolving in Europe around 430,000 years ago.

80,000-35,000 years ago.  There was another wave of human migration out of Africa, and humans reached Europe, Asia, and Australasia.  During this time, humans interbred with Neanderthals and Denisovans.  The best evidence for this comes from studies of "ancient DNA."  In the 1980s and 1990s, scientists discovered that it was possible to recover DNA from mummified human specimens and ancient bones.  In 1997, Svante Paabo and his colleagues reported that they had sequenced Neanderthal mitochondrial DNA.  In 2010, Paabo and his colleagues published a draft of the entire Neanderthal genome; and they suggested that there was interbreeding between Neanderthals and humans.  They also published a genetic analysis of another archaic human population--the Denisovans.  Later, it was shown that humans had interbred with Denisovans.

Since it was humans who had migrated out of Africa who interbred with Neanderthals, scientists have long assumed that while all present day non-African individuals carry some Neanderthal ancestry in their DNA, there would be no Neanderthal ancestry in African populations.  But in 2020, a new genetic study showed that African individuals do indeed show some Neanderthal ancestry (Chen et al., 2020).  This can be explained by ancient Europeans with Neanderthal genes migrating back to Africa.  So we now know that remnants of Neanderthal genomes are found in every human population.

Proportions of Neanderthal DNA in human populations today range as high as 2 percent.  Proportions of Denisovan DNA range as high as 5 percent--mostly in Asian and Australasian populations (Reich, 2018, 58-59).  This evolution by hybridization has benefitted human beings.  For example, modern humans in parts of Europe and East Asia have Neanderthal keratin protein genes that help them grow skin and hair suitable for the colder regions originally occupied by Neanderthals.  And many Tibetans today have a Denisovan gene active in red blood cells that help them breath the thin air of the Tibetan high altitudes (Reich, 2018, 65).

Thus, the scientific study of ancient DNA allows us to trace the entire history of human migration and interbreeding across time and space.  This research supports two general conclusions.  First, the evolution of human nature is about the mixture of populations, so that there is no such thing as a pure population or race.  Second, the people who live in a particular place today almost never descend exclusively from the people who lived in the same place in the distant past.  These two conclusions refute racism (by denying the "purity" of racial differences) and ethnic nationalism (by denying that national identity can be based on ancestral descent from a single founding population).

65,000-50,000 years ago.  The ancestors of the Aboriginal Australians arrived from Southeast Asia.  They remained foragers (living by hunting, gathering, and fishing), with little or no farming, until the British arrived in 1788.

20,000-13,00 years ago.  There is genetic evidence for at least four prehistoric migrations of Eurasians migrating to the Americas (Reich, 2018, 155-60).  By about 14,000 years ago, these human migrants had reached the southern tip of South America.  When sea levels were low enough for a land bridge to emerge in what is now the Bering Strait region, these people could walk across to Alaska.  In 1590, the Jesuit naturalist Jose de Acosta was the first person to speculate that human hunter-gatherers first crossed from Asia to an America without humans.  John Locke learned this from his reading of Acosta, which supported his conclusion that the American Indian hunter-gatherers were "still a Pattern of the first Ages in Asia and Europe" (ST, 108).

13,000-9,000 years ago.  Agriculture developed for the first time in the Fertile Crescent of the Near East.  The first European farmers were genetic mixtures of local hunter-gatherers and Anatolian farmers. Farming was then spread by migrants throughout Eurasia over the next few thousand years.

6,000-4,000 years ago.  Early wheel technologies and writing systems emerged and were spread by migrants.

9,000-4,500 years ago.  During this period--the Early Bronze Age--the Yamnaya culture emerged in the center of the Great Steppe north of the Black and Caspian seas.  The Yamnaya population arose from a genetic mixture of Iranian farmers and local hunter-gatherers.  They were pastoralists whose economy was based on sheep and cattle herding.  They were innovative in their use of the newly domesticated horse and the hitching of animals to wagons and chariots with wheels.  They eventually spread over a vast expanse of the steppe--5,000 miles from Hungary in Europe to the Altai Mountains in central Asia and south into India where they conquered the Indus Valley Civilization.  They developed the first form of Indo-European Language, and their expansion created the family of Indo-European languages that stretches across Europe, India, and parts of East Asia.  By sometime after 4,500 years ago, the Yamnaya had migrated all the way to the British Isles.  90 percent of the people who built Stonehenge--people with no Yamnaya ancestry--were replaced by Yamnaya people (Reich, 2018, 99-121).

The Yamnaya were a stratified male-dominated society in which a few elite males ruled.  The ancient DNA data show that.  The Y chromosomes of the Yamnaya were mostly of only a few types, which shows that a few males succeeded in spreading their genes.  Moreover, these few Y-chromosome types of the Yamnaya are predominant today in Europe and India, which shows that the Yamnaya expansion allowed the most powerful Yamnaya male descendants to be more successful in mating than men from the local groups (Reich, 2018, 237-41).

This reminds us that because of the biological differences between the sexes, a single male can have far more children than a single female, and consequently powerful men can potentially have a far greater imprint on the human genome than powerful women.

As we will see, this ancient history of an Indo-European culture was transformed--beginning in the 19th century--into the myth of the "Aryan race" that has supported the ideologies of Nazism, Hindutva (Hinduism), and the Alt-Right Nietzscheanism of Trumpists like "Bronze Age Pervert."

117 AD.  The Roman Empire reaches its greatest extent under Trajan.

500.  Silk Roads link the Mediterranean region and China.

700s-1000s.  Viking ships cross the Atlantic.

1206-1368.  The Mongols formed the largest contiguous empire in history.  Genghis Khan (1162-1227) was the founder and the first khan of the Mongol Empire.  Genetic evidence indicates that 8 percent of the males living in East Eurasia today share a characteristic Y-chromosome sequence that was probably Genghis Khan's Y chromosome, which shows his millions of direct male-line descendants across the territory occupied by the Mongols (Zerjal et al., 2003).

1320-1350.  New Zealand was discovered and settled by Polynesians, who developed the distinctive Maori ethnic cultural group, which is today the second largest ethnic group in New Zealand, behind the European New Zealanders.

1492.  Columbus landed in the Bahamas, although he thought it was India.  He encountered the Taino people--the indigenous people of the Caribbean islands. Thus began the first global network of immigration, interbreeding, and trade encompassing most of the Earth.

1519.  Hernan Cortes conquered the Aztec capital--Tenochtitlan--present-day Mexico City.  Within four years of the 1519 campaign, Martin Cortes, "el Mestizo," was born: his father was Hernan Cortes, his mother was Cortes's Aztec mistress.  Thus began the Darwinian evolution of Indigenous Americans through genetic and cultural hybridization.  Today, in Mexico (with a population of 127 million), 70% of the people are mestizos, 14% Amerindians, and 15% whites.  As I have argued previously, this refutes the idea of "American genocide": there are more people in the Americas today with Indigenous American genes than there were when Columbus landed in 1492.

1526.  This was the year of the first transatlantic slave voyage from West Africa to Brazil.  Thus began one of the most massive, forced migrations in human history.  By the 1780s, over 75,000 African slaves were arriving every year in the Americas.

1693.  John Locke wrote an essay "For a General Naturalization" that was probably written in support of the General Naturalization Bill of 1693.  "Naturalization is the shortest and easiest way of increasing your people," Locke declared at the beginning of the essay. Increasing population is important, he explained, because "people are the strength of any country or government," and it's "the number of people that make the riches of any country."  What we see here is what evolutionary scientists call cultural group selection through migration and assimilation, in which countries with cultural traditions of freedom have higher fitness than countries that are less free.  John Locke understood this, which is why he argued that free societies benefited from having open borders, so that they could attract migrants from less free societies.  The freer societies with a growing population of productive and inventive people become the more prosperous societies.   We see that today because the people in the less free countries want to migrate to the freer countries (as measured by the Human Freedom Index).

1718.  Great Britain's Transportation Act formalized the forced migration of convicts.  From 1718 to 1775, as many as 50,000 convicts were sent to the British colonies in America.  After the British lost the Revolutionary War in 1783, they decided to look elsewhere for penal colonies.  In 1788, they established their penal colony at Botany Bay (Sydney) in Australia.

1776.  Thomas Jefferson's original draft of the Declaration of Independence contained two grievances against King George III concerning immigration.  On the one hand, the King was accused of obstructing the passage of laws that would encourage the free migration of foreigners to America and then facilitate their naturalization.  On the other hand, the King was denounced for promoting the forced migration of African slaves through the slave trade, which was said to be a "cruel war against human nature itself."  The passage condemning the slave trade was excised from the final draft, however, because some of the delegates from South Carolina and Georgia wanted to continue the foreign importation of slaves, and because some people in the northern colonies had engaged in the commercial shipping of slaves.

I have written about Jefferson's disturbing behavior in adopting his slave Sally Hemmings as his concubine, who bore at least six of his children.  That the principal author of the Declaration of Independence, who affirmed natural human equality and who denounced slavery as a violation of human nature, could not only own black slaves but also exploit them for his sexual gratification forces us to think about the human nature of slavery, its corrupting effect on slaveowners, and the evolution of racial mixing.  Moreover, interracial sexual mating undermines the claims of the racist that the races can and should remain "pure" in their separation. 

1850.  The U.S. Congress passed the Fugitive Slave Law of 1850 to make it easier for Southern slaveowners to recapture slaves who had run away to the Northern free states.  The law made it a federal crime for anyone to help fugitive slaves avoid capture.  This denied the freedom of internal migration within the nation--the freedom to vote with one's feet by running away from enslavement in the American South.  Many Americans resisted this law as an unjust law that violated natural human rights.  A black abolitionist like Frederick Douglass, who had himself run away from his slave master, were especially eloquent in defending the natural human right to run away--to migrate--to some place where one could be free.  

Some years later, Douglass defended a general "right of migration" for all human beings.  And he argued for the greatness of America as a "composite nation" open to all races, creeds, and religions and to all foreigners who would come to America searching for freedom.   He compared the "repugnance to the presence and influence of foreigners" to the "prejudice of race and color" that had supported chattel slavery:  both express the natural human propensity to tribalism or xenophobia that favors us against them.  Even if all other nations manifest this natural tribalism in limiting migratory rights and other human rights to themselves, America is unique in being the nation dedicated to human rights for all--"the faithful application of the principle of perfect civil equality to the people of all races and of all creeds."  And therefore, America must recognize the right of locomotion or migration as a right for all of humanity, so that America must have open borders.

TO BE CONTINUED . . .

REFERENCES

Garcia-Bertrand, Ralph, and Rene J. Herrera. 2018. Ancestral DNA, Human Origins, and Migrations. Elsevier.

Goldenberg, David M. 2003. The Curse of Ham: Race and Slavery in Early Judaism, Christianity, and Islam. Princeton: Princeton University Press.

Goldin, Ian. 2024. The Shortest History of Migration.  New York: The Experiment.

Reich, David. 2018. Who We Are and How We Got Here: Ancient DNA and the New Science of the Human Past. New York: Pantheon Books.

Zerjal, T., et al. 2003. "The Genetic Legacy of the Mongols."  American Journal of Human Genetics 72: 717-21.

The Evolution of the Natural Desire for Music

NATURAL DESIRES

In previous posts, I have argued that if the good is the desirable, then human ethics is natural insofar as it satisfies the natural human desires that naturally win social approval as useful or agreeable to oneself or to others.  The satisfaction of these natural desires constitutes a natural standard for judging social life as either fulfilling or frustrating human nature, although prudence is required in judging what is best for particular people in particular social circumstances.  

By this standard, the modern bourgeois liberal regime can be recognized as the best regime so far in human history, because no other regime has satisfied those natural desires so well for so many people.  Or, to put it another way, the liberal regime has been more successful than any other regime so far in securing for human beings their equal liberty for the pursuit of happiness.

In Darwinian Natural Right and Darwinian Conservatism, I have argued that there are at least twenty natural desires: human beings generally desire (1) a complete life, (2) parental care, (3) sexual identity, (4) sexual mating, (5) familial bonding, (6) friendship, (7) social ranking, (8) justice as reciprocity, (9) social membership, (10) political ambition, (11) war, (12) freedom from domination,  (13) health, (14) beauty, (15) property, (16) speech, (17) practical arts, (18) aesthetic pleasure from art, music, dance, and storytelling, (19) religious transcendence, and (20) intellectual understanding.

I have argued that these twenty natural desires are universally found in all human societies, that they have evolved by natural selection over millions of years of human evolutionary history to become components of the species-specific nature of human beings, that they are rooted in the neurophysiological mechanisms of the brain, that they direct and limit the social variability of human beings as adapted to diverse ecological circumstances, and that different individuals with different temperaments and talents will rank these desires differently.  

Lockean liberal individualism recognizes that there is no single summum bonum or highest good for all human beings because there is no one right way to rank those natural desires.  But each individual will have a summum bonum--a ranking of those natural desires with perhaps one being the highest--depending on the propensities and capacities of each individual. A Socrates will rank intellectual understanding as the highest good.  A Saint Augustine will rank religious transcendence as the highest.  An Abraham Lincoln will rank political rule as the highest.  A General George Patton will rank war as the highest.

There is evidence that this pattern of twenty desires developed in the Late Pleistocene environment of our hunting-gathering ancestors, from about 130,000 years ago up to the invention of agriculture about 5,000 years ago.  This was the evolutionary environment in which human nature was shaped by natural selection.  This is what John Locke called "the state of nature."  The historical record of human civilization since the development of agriculture shows human beings as moved by these twenty desires.

I now include the natural desire for music as one of the twenty natural desires--as belonging to aesthetic pleasure.  I was recently prompted to think more about this when I attended the Grand Rapids Symphony Orchestra's performance of Ludwig van Beethoven's Ninth Symphony or Choral Symphony--indeed, it was the first symphony to include choral singing--which is famous for its "Ode to Joy" chorus in the last movement.

THE MYSTERY OF MUSIC

For Charles Darwin, in The Descent of Man (1871), music was a mystery:

As neither the enjoyment nor the capacity of producing musical notes are faculties of the least use to man in reference to his daily habits of life, they must be ranked amongst the most mysterious with which he is endowed.  They are present, though in a very rude condition, in men of all races, even the most savage; but so different is the taste of the several races, that our music gives no pleasure to savages, and their music is to us in most cases hideous and unmeaning (2004, 636).

Darwin observed that while the nations of Western Europe were similar in their music, there were cultural differences in the way they interpreted music.  And in the eastern regions of the world, there were very different languages of music.

He saw evidence that our prehistoric human ancestors had music.  Prehistoric flutes made out of the bones and horns of reindeer found in caves together with flint tools was evidence of instrumental music.  The arts of singing and dancing also seemed to be very ancient and practiced today by all human races.  Poetry could be included as an ancient form of music because it arose from singing.

Darwin also saw that the anthropomorphous monkeys and apes use their vocal organs to express strong emotions through musical tones and rhythm--particularly during the season of courtship, when males are trying to attract females for mating and to repulse their male rivals.  For Darwin, this was to be explained as evolving by sexual selection rather than natural selection. 

From all of this evidence, Darwin inferred that "musical notes and rhythm were first acquired by the male or female progenitors of mankind for the sake of charming the opposite sex," and that "musical sounds afforded one of the bases for the development of language."  He noted, however, that Herbert Spencer had come to the opposite conclusion--"that the cadences used in emotional speech afford the foundation from which music has been developed" (2004, 638-39).

Darwin thus raised, either explicitly or implicitly, almost all the questions about the evolution of music that evolutionary scientists have debated over the past 150 years.  

(1) Is music a single propensity or capacity?  Or does music have many different components, such as rhythm, melody, and harmony, that produce many different forms of music--song, instrumental music, dance, and poetry?  

(2) Is music a universal human instinct?  Or does the cultural diversity of music show that it is not a human universal?  

(3) Did music evolve by natural selection or sexual selection?  Or did it arise only as a by-product of other traits that were selected for--such as language?  

(4) Is music unique to human beings?  Or can we find at least some of the rudimentary components of music in other animals?

(5) Is there any fossil record of prehistoric human music?

(6) If music did arise through some process of evolutionary selection, what was it selected for?  What is its ultimate function?  Or does it potentially serve many different functions?

(7) What is the evolutionary relation between music and language?  Did one come before the other?

(8) Can we identify the neurobiological mechanisms for music--perhaps a "music module" in the brain?  Or does music arise from many interconnected networks in the brain?

Although there has been no final resolution of the debates over these questions, it is now possible to plausibly argue for some tentative answers.

EVOLUTIONARY THEORIES OF MUSIC

We should begin by distinguishing music and musicality, which allows us to see that while musicality is biologically universal, music is culturally variable (Honing 2018; Fitch 2018).  Musicality includes components such as melodic, rhythmic, and harmonic cognition; and it is that part of our biological nature that gives human beings in all cultures the capacity and the propensity to generate and enjoy all forms of music.  But music in all its variety is culturally constructed through the biological power of human musicality.  Music then is like language in its biological universality and cultural diversity.  All human beings normally have a biological instinct for learning and using a language.  But different human beings will learn different languages in different cultures.

There are at least four explanations for how musicality is grounded in human biology.  The first is Darwin's theory of sexual selection in which music evolved as a way of attracting sexual mates and thus increasing reproductive success (Miller 2000; Prum 2017).  This theory often includes Darwin's idea that the neural structures that evolved for musicality were precursors of both music and language.

A second theory is that music originated in the maternal music-like vocalizations to infants, including soothing lullabies, and the dance-like maternal movements with infants that promote parent-infant bonding and the well-being of infants (Dissanayake, 2008, 2021).

A third theory is that music evolved to promote and maintain group cohesion.  Among prehistoric human ancestors, group singing and dancing would have glued people together in large groups (Dunbar, 2010, 2012).

These three theories are adaptationist explanations that see music as an evolutionary adaptation by natural or sexual selection.  But a fourth theory explains the origin of music not as originally an evolutionary adaptation but as an evolutionary by-product of other skills that were adaptive.  Music could have been originally a human invention--like the control of fire and the invention of cooking--that became universal in human societies because it was advantageous for human life, and then through gene-culture coevolution, this could have led to neurophysiological changes that deepened the grounding of music in human biology (Patel, 2010, 2018).

Music as Social Bonding

There is still another theory, however, that can embrace all four of these theories.  Patrick Savage and his colleagues (2021) have argued for the hypothesis that human musicality is a coevolved system for social bonding.  Actually, this can be seen as an expanded version of the "group cohesion" theory.  Let's define the three key terms in this statement

First, as already indicated, musicality denotes the biological capacities of all human beings that allow us to perceive and produce music, while the word "music" denotes the diverse musical systems produced by different cultures.

Second, social bonding refers to all kinds of affiliative connections that bind two or more people into a group.  Such social bonding would have enhanced the survival and reproduction of our prehistoric human ancestors by enhancing protection from predators, cooperative child-rearing, collaborative foraging and hunting, and the expansion and defense of territories (Dunbar, 2012b; Hrdy, 2009).  Music and dance would have promoted such social bonding by synchronizing and harmonizing the emotions, thoughts, and actions of two or more individuals.  This would have strengthened mate bonding, infant care, and group cohesion.

I have written about the natural desire for membership in a society and how such membership requires markers of social identity.  Music and dancing could have provided those markers for our prehistoric ancestors.  We see that today in how singing a national anthem (like America's "Star-Spangled Banner" or "My Country, 'Tis of Thee") can strengthen the emotional bonding of people in a nation.

But while social bonding through music sounds warm and cozy, we should recognize the dark side of this:  in-group social bonding often means hostility toward out-groups--the tribalism of "us" versus "them."  Throughout history, tribalist movements (often evil like the Nazis) have used music to move their supporters to unite in attacking their perceived enemies.

We should also recognize that while social bonding might be the original overarching function of music, that does not mean that this is its only function.  Once music has become part of our evolved human nature, we can use it for purposes other than social bonding.  For example, people enjoy playing or listening to music alone.  Sometimes they do this to evoke memories of some previous social experience of the music--such as the lover who listens to music that he associates with his beloved.  But sometimes people listen to music alone just to regulate their moods.

The third key term in the music as social bonding hypothesis is coevolved.  This means that musicality has evolved through a process of gene-culture coevolution, which has been a topic in previous posts.  It is possible that "musical behavior first arose as a human invention and then had (unanticipated) beneficial effects on social cohesion" (Patel, 2018, 118).  This then created cognitive and social niches in which both biological and cultural selection could favor those particular forms of music that most effectively promoted social bonding.  This is what I have previously identified as symbolic niche construction.

This is all very clever, you are surely thinking, but isn't it just speculative "just-so storytelling" that can't be empirically verified or falsified--particularly since the fossil and archaeological record of prehistoric human evolution offers very little evidence of when and how our ancient ancestors made music and for what purposes?

Well, actually there is some fossil and archaeological evidence, even if limited, for prehistoric music.  And this is only the first of five kinds of evidence that can support the music as social bonding theory.

Five Kinds of Evidence

(1) As we've seen, Darwin considered the discovery of Ice Age bone flutes as clear evidence for the antiquity of music among our earliest human ancestors.  As indicated in a previous post, the earliest bone flutes have been dated to over 35,000 years ago (Conard, Malina, and Munzel, 2009).  This is only a sample of an extensive record of prehistoric musical instruments (Morley, 2013).

(2) The second kind of evidence that music is part of our evolved human nature is the cross-cultural evidence for music as a human universal.  Music, like language, is manifest universally in all known cultures (Brown, 1991).  Moreover, Mehr et al. (2019) found 20 widespread functional contexts in which music was important:  (1) dance, (2) infancy, (3) healing, (4) religious activity, (5) play, (6) procession, (7) mourning, (8) ritual, (9) entertainment, (10) children, (11) mood/emotions, (12) work, (13) storytelling, (14) greeting visitors, (15) war, (16) praise, (17) love, (18) group bonding, (19) marriage/weddings, and (20) art/creation.  Notice that all of these functional contexts relate to social bonding.

Also, Savage et al. (2015) have identified 18 features of musical structure that are widespread in all or most cultures.  Most of these support coordinated music-making:

Throughout the world, humans tend to sing, play percussion instruments, and dance to simple, repetitive music in groups, and this is facilitated by the widespread use of simple-integer pitch and rhythm ratios, scales based on a limited number of discrete pitches (usually no more than 7), and isochronomous beats grouped in multiples of two or three. . . . The widespread use of simple, discrete meters and scales also enables multiple people to memorize and coordinate their performances.  These widespread musical properties have few direct parallels in language.  Group coordination provides a common purpose that unifies the cross-cultural structural regularities of human music (Savage et al., 2021, 8).

This is impressive cross-cultural evidence for the universality of musicality as an evolved instinct of human nature that supports social bonding.

(3) There is also developmental evidence for the early development of the social functions of music in infancy and early childhood (Savage et al., 2021, 9).  Infants respond to songs from their adult caregivers, such as lullabies, with similar, cross-culturally recognizable acoustic features.  Infants respond differently to lullabies as distinguished from play-songs.  Music improves parent-infant social bonding.  Young children also show more sociable behavior when they are engaged in group musical activities.  Music shapes children's social bonds.

(4) A fourth kind of evidence for musicality as promoting social bonding is social psychological evidence.  Social psychologists have conducted behavioral experiments that show how musical behavior enhances social cooperation (Savage et al., 2021, 9-10).  For example, when people dance in synchrony, they feel connected to the group with whom they're dancing.  And people who sing in large choirs develop feelings of social closeness with their fellow singers.

(5) The fifth kind of evidence for music as rooted in evolved human nature has to do with the neurobiological proximate mechanisms for music and social bonding.  There is some evidence "that the dopaminergic reward system interacts with the endogenous opioid system and the release of oxytocin, ultimately providing opportunities for individuals to synchronize their moods, emotions, actions, and/or perspectives through musical engagement," which would serve music's social bonding functions.  Moreover, "people who frequently experience chills when listening to music show high white matter connectivity between auditory, social, and reward-processing areas" (Savage et al., 2021, 10-12; Sachs et al., 2016).

One indirect way to infer how the normally functioning brain supports musicality and social bonding is to study those people with abnormal brains that cause some of them to be unable to "hear" music at all and others to be extraordinarily responsive to music.  This is what Oliver Sacks did in his book Musicophilia: Tales of Music and the Brain (2007).  He described many cases of people with amusia--being unable to recognize or enjoy music.  In some cases, this was congenital (from birth).  In others, it was acquired (from some injury to the brain).  (The Wikipedia article on "Amusia" is a good short survey.)

Sacks tells the story of D.L., a seventy-six-year-old woman who had never heard music.  Although she came from a musical family in which everyone played an instrument, she never liked music because it just sounded like noise to her.  As a little girl, a family friend who was a specialist in teaching music tested her with pitches, but she could not tell if one note was higher than another.

When people asked her what she heard when music was played, she would say, "If you were in my kitchen and threw all the pots and pans on the floor, that's what I hear!"

She couldn't recognize the simplest tune, such as "Happy Birthday to You."  On the other hand, she seemed to have a good sense of rhythm in her body because as a girl she loved to tap dance.

While D.L. was an example of congenital amusia, Sachs also saw cases of acquired amusia.  Professor B. was a gifted musician who had played with the New York Philharmonic.  But after having a stroke, he was suddenly unable to discern a tune.  He perceived pitch and rhythm, but he could not synthesize them into a melody.

While Sacks saw Professor B. as an example of melody deafness, he saw Rachel Y. was an example of harmony deafness.  She had been a talented composer and performer.  But then she was in a car accident where she suffered severe head and spine injuries.  Afterwards, she heard all music as discrete lines but was unable to perceive the harmonic sense of chordal passages.  She could not harmonize different voices and instruments.

In contrast to these cases of musical deafness, Sacks also studied cases of hypermusicality--people who show an extraordinary love of music.  Some of the best cases were people with the congenital disorder known as Williams Syndrome.  They are visibly distinctive because of their elfin-like faces.

Williams syndrome is a rare genetic condition that causes facial characteristics including epicanthal folds at the eyes, large ears, an upturned nose, full cheeks, a wide mouth, a small jaw and small teeth.

Williams Syndrome is caused by the deletion of 26-28 genes on the long arm of chromosome 7.  Individuals with Williams Syndrome typically have mild to moderate intellectual deficits (IQs around 60), cardiovascular disease, and the distinctive facial characteristics just indicated.  Their cognitive profile includes normal language and facial processing skills but deficient visuospatial abilities (Martens, Wilson, and Reutens, 2008).

The personality of Williams Syndrome people is hypersociable: they're unusually friendly and loquacious--longing to connect and bond with others.  They also show a heightened interest in and emotional responsiveness to music and musical activities (Thakur et al., 2018).  Sacks tells the story of Gloria Lenhoff, a woman with Williams Syndrome who could sing over 2,000 operatic arias in more than 30 languages.  But she could not add five plus three.

This seems to confirm Howard Gardner's theory of "multiple intelligences"--that rather than having some kind of general intelligence (perhaps measured by IQ scores), human brains have as many as eight separate kinds of intelligence.  Williams Syndrome people seem to have high social intelligence and musical intelligence but are deficient in logico-mathematical intelligence.

Apparently, this has something to do with the abnormal size and shape of the brain in Williams Syndrome people.  Their brains on average are about twenty percent smaller than normal brains.  And the ratio of frontal lobe volume to combined parietal and occipital lobe volume is abnormally high.

But the primary point here for evolutionary theories of music is that the combination in Williams Syndrome people of hypermusicality and hypersociability seems to support the social bonding theory of the origin of music.  

My next post will be on "The Political History of Beethoven's Ninth Symphony."  That post will include a list of bibliographic references.

E. O. Wilson and J. Philippe Rushton: Scientific Racists? Or Can the Science of Race Affirm Human Freedom and Equality of Rights?

In January of 1989, I was in San Francisco for the Annual Meeting of the American Association for the Advancement of Science (AAAS).  I attended a "Symposium on Evolutionary Theory, Economics, and Political Science," which had been organized by Roger Masters.  That caught my attention because I was spending a sabbatical year at Stanford University working on a project for applying evolutionary theory to political philosophy, and the writing of Masters had influenced my thinking.  At that symposium, J. Philippe Rushton, a professor of psychology at the University of Western Ontario, presented a paper on "Evolutionary Biology and Heritable Traits (With Reference to Oriental-White-Black Difference)."  

He argued that the three major races--Orientals (Mongoloids or Asians), Whites (Caucasoids or Europeans), and Blacks (Negroids or Africans)--consistently differed in "Life History Strategy."  Blacks have the fastest strategy: they live fast and die young.  Orientals have the slowest strategy: they live slow and invest in the future.  Whites are intermediate between these two poles.  On average, Orientals are slower to mature, less fertile, less sexually active, less aggressive, and have larger brains and higher IQ scores.  At the opposite pole, on average, Blacks are fast to mature, more fertile, sexually promiscuous, very aggressive, and have smaller brains and lower IQ scores.  Whites fall in the middle, but closer to Orientals than to Blacks.  This three-way pattern of racial differences arises from evolutionary and genetic causes rather than purely cultural causes.  Blacks evolved to be adapted to the tropical climate of sub-Saharan Africa.  Whites evolved to be adapted to the cooler climates of Europe.  Orientals evolved for the coldest Arctic lands. 

Even as he argued that these race differences are genetically based, Rushton insisted that this was not an argument for genetic determinism.  There were two reasons for this.  First, since there is enormous variability within each race, and since the distribution of traits shows a great overlap between the races, one cannot generalize from a group average to any particular individual.  Second, he stressed that only about 50% of the variance is genetic, and about 50% is due to the environment; and even the genetic effects are necessarily mediated by neuroendocrine and psychosocial mechanisms, which allows the individual and society to exercise some control over this.

In the technical terms of the evolutionary science of life histories, Rushton explained, Orientals are more "K strategists," Blacks are more "r strategists," and Whites are intermediate between these two.  He was employing a theory of "r and K selection" developed by Edward O. Wilson and others (MacArthur and Wilson 1967; Wilson 1975, 99-103).

In the equations used by population ecologists to describe the growth of populations of organisms, r represents the slope of the line showing exponential growth, while K represents the carrying capacity of a habitat for a certain kind of organism.  Organisms identified as r strategists typically live in unstable, unpredictable environments, where the best reproductive strategy is to produce lots of offspring rapidly, while expending little parental investment in any one offspring.  The idea is to flood the habitat with progeny so that, while many of them will die, at least a few will survive to reproduce.  Organisms that are r selected tend to be small, short-lived, fertile at an early age, fast maturing, with a strong sex drive, little care for offspring, and less intelligent (smaller brains).  Typical examples of r strategists are oysters, salmon, frogs, and insects.

K strategists, on the other hand, occupy more stable environments, in which the best reproductive strategy is to live close to the carrying capacity of their habitat by producing only a few offspring and investing a lot of parental care in each offspring.  Organisms that are K selected tend to be large, long-lived, fertile at a later age, slow maturing, with a weak sex drive, with extensive parental caregiving, and more intelligent (larger brains).  Examples of K selected organisms are elephants, the great apes, and humans.  Indeed, humans are the most K selected species of all.

While many biologists have used r/K selection theory to explain differences between species, Ruston's novel idea was to use the theory to explain differences between races or subspecies within the human species.  While humans are the most K selected species, Ruston argued, some human races were a little less K selected and more r selected than other races.  Orientals are more K selected than Whites, and Whites are more K selected than Blacks.

As I listened to Ruston speak, I noticed that there were many newspaper reporters in the room, and I thought: This guy is going to stir up a big public controversy.  And, indeed, as soon as the Q&A began, the reporters began asking hostile questions.  I learned that Rushton had sent out press releases a week before describing his paper.  He wanted publicity--bad publicity!--and he got it.  Over the next few days, newspapers around the United States and Canada published stories about the firestorm he had created by presenting a scientific theory of racial differences that seemed blatantly racist.  I thought to myself that this guy must be so narcissistic--so obsessed with being the center of attention--that he will pronounce the most offensive ideas about racial differences to create the notoriety that comes from being regarded as the most outrageous kind of racist.

What I remember most about Rushton's speech was his obsession with the size of black men's penises.  One of the primary data points for his theory was his claim that black men's penises were bigger than white men's and much bigger than Asian men's.  You can see why Rushton began to appear on American television talk shows by Geraldo Rivera and Phil Donahue to defend his ideas about racial differences.

Rushton's 1989 AAAS paper was eventually published in 1992, and it can be found online.  Later, he elaborated his reasoning in a big book--Race, Evolution, and Behavior: A Life History Perspective (1997).  He also published a special abridged edition of this book (2000), which can also be found online.

I was recently reminded of Rushton when I read some essays at the New York Review of Books (here) and Science for the People (here) showing that Edward O. Wilson had an extensive correspondence with Rushton--who died in 2012--that showed Wilson's support for Rushton's scientific theory of race differences.  A few weeks ago, I wrote a post criticizing Monica McLemore for identifying Wilson as a racist without providing any evidence for this in Wilson's published writing.  At that time, I had no knowledge of Wilson's correspondence with Rushton, which suggests that in his private correspondence Wilson was willing to express his sympathy for the scientific racism of people like Rushton.  Wilson's correspondence is found in his papers at the Library of Congress.  An index to the papers can be found online.  I have not examined the papers.  But I will assume that these two essays accurately quote from the correspondence with Rushton.

Some of the scientists who at first defended Wilson from McLemore's charge of racism--such as Jerry Coyne--have said that this evidence of Wilson's support for Rushton forces them to reconsider whether Wilson really was a scientific racist.

From what I see in the correspondence and in Wilson's published writing on race differences, I draw two conclusions.  First, Wilson's correspondence showed bad judgment in supporting Rushton, because Rushton presented his theory of race differences in such a way that it could be easily interpreted as confirming scientific racism.  This became very clear in later years when Rushton allied himself with Jared Taylor's online journal American Renaissance, which promotes Taylor's argument for promoting the "white identity" of America and restricting non-white immigration.

My second conclusion is that Wilson was not himself a racist, because he saw that the science of race differences was compatible with the Lockean liberal principle of natural human equality of rights, which denies racist xenophobia and white nationalism.

Wilson's correspondence with Rushton began in 1986.  Wilson sponsored the publication of Rushton's paper "Gene-Culture Coevolution of Complex Social Behavior: Human Altruism and Mate Choice" in the Proceedings of the National Academy of Sciences of the United States (PNAS).  But there was nothing in this paper about race differences.

In 1987, Rushton asked Wilson to sponsor another paper for publication in PNAS.  But this time, the paper was on race differences; and for that reason, Wilson had to decline to sponsor it.  Wilson explained to Rushton: "You have my support in many ways, but for me to sponsor an article on racial differences in the PNAS would be counterproductive for both of us."  He told a story about being attacked as a racist and then remarked: "I have a couple of colleagues here, Gould and Lewontin, who would use any excuse to raise the charge again.  So I'm the wrong person to sponsor the article, although I'd be glad to referee it for another, less vulnerable member of the National Academy."  Wilson's feeling of vulnerability in being exposed to the charge of racism must explain why Wilson's support for Rushton was restricted to private correspondence and never expressed in any public statement.

After Rushton's presentation at the AAAS convention on January 19, 1989, he found himself under attack.  The Premier of Ontario called for his dismissal from his faculty post at the University of Western Ontario.  The Ontario Provincial Police announced that he was under criminal investigation.  At his university, there were student protests against him.  Then, on July 1, he received a report from the Promotion and Tenure Committee of his department that rated his performance for 1988-1989 as "Unsatisfactory."  The report said that members of the committee were "of the unanimous opinion that your work on the genetic basis of race differences is substantially flawed and that your published record indicates serious scholarly deficiencies."  Rushton appealed this decision.  He cited his numerous publications as evidence that his research record was good.

On April 4, 1990, Wilson wrote to the Appeals Committee at the University of Western Ontario to support Rushton's appeal.  Wilson said that Rushton's data and interpretation were "sound, being adapted in a straightforward way from well documented principles of r-K selection in biology."  He said that many biologists would agree with this, and he explained: "You may wonder why almost none have published their opinions.  The answer is fear of being called racist, which is virtually a death sentence in American academia if taken seriously.  I admit that I myself have tended to avoid the subject of Rushton's work, out of fear."  Rushton won his appeal, and he wrote to Wilson to thank him for his support.

It seems that Wilson did not publicly state his support for Rushton's work out of "fear of being called racist."  Those who wrote the essays for Science for the People and The New York Review of Books assume that he feared being correctly called a racist.  But I think his published writing about race differences suggests that he feared being falsely called a racist.

Wilson's published writing about race is remarkably skimpy.  His most extensive writing on race that I have noticed is in the fourteen pages of his 1953 article on the "subspecies concept" (Wilson and Brown 1953) and four pages in his 1978 On Human Nature (47-51).  

In their NYRB essay, Borrello and Sepkoski say that in 1975, in the last chapter of Sociobiology, Wilson "suggested, among other things, an evolutionary and genetic basis for 'the behavioral qualities that underlie the variations between cultures,' as well as for 'marked racial differences in locomotion, posture, muscular tone, and emotional response that cannot be reasonably explained as the result of training or even conditioning within the womb.'" But the passage they quote does not appear in the 1975 Sociobiology.  It appears in the 1980 abridged edition of Sociobiology (274).  This passage originally appeared in On Human Nature (48-49), but without the phrase "marked racial differences." 

For interpreting Wilson's understanding of race, the best place to begin is his early article on the subspecies concept, because for biologists, the term "race" is equivalent to the term "subspecies."  Within each species, there is heritable phenotypic variation.  Indeed, without such variation within each species, evolution by natural selection would be impossible, because there would be no variation for natural selection to work on.  When this genetic phenotypic variation shows sufficient geographic structuring, so that the geographical origins of individuals can be determined from their genetic and phenotypic characteristics, then biologists can identify these geographic clusters as subspecies or races.  These races can become "incipient species" that eventually might evolve into species.

We are all familiar with the Linnean Latinized binomial taxonomic label for a species that denotes the genus and the species.  For example, the chimpanzee is Pan troglodytes--Pan for the genus, troglodytes for the species.  The other great ape that belongs to this genus is the bonobo--Pan paniscus--which for a long time was assumed to be a subspecies of chimpanzees--the pygmy chimpanzee.  That indicates the fundamental problem in all taxonomy: the boundaries are often so fuzzy that it's hard to distinguish between closely related species and between closely related subspecies, which leads to endless debates among taxonomists as to how to draw the boundaries.

Taxonomists employ a Latinized trinomial label for a subspecies.  The four generally recognized subspecies of chimpanzees have four such labels (Stanford 2018, 184-90).  The central chimpanzee--Pan troglodytes troglodytes--is found across a wide area of central African rain forest.  The western chimpanzee--Pan troglodytes verus--is found in the Tai National Park and surrounding forests in western Africa.  The eastern chimpanzee--Pan troglodytes schweinfurthii--is found in central and eastern Africa, and it's the most studied chimpanzee, including Jane Goodall's chimpanzees in Gombe.  The Nigerian-Camaeroonian chimpanzee--Pan traglodytes ellioti--is found in forested areas across Nigeria and Cameroon, and it has been named only in recent years.  Although it is not generally recognized, primatological taxonomist Colin Groves has argued that there is a fifth subspecies--the southeastern chimpanzee (Pan troglodytes marungensis)--that arises from the variation between the northern and southern populations of P. t. schweinfurthii. 

Comparisons of genetic variation between humans and great apes have shown that the degree of genetic differentiation among chimpanzee subspecies is about the same as among human races (Fischer et al. 2006).  So we have a choice.  If we deny that human races are real, we must also deny that chimpanzee races are real.  Or if we see that chimpanzee races are real, we must also see that human races are real.

In "The Subspecies Concept and Its Taxonomic Application," Wilson and Brown criticize the subspecies concept because of its "subjective and even arbitrary nature" (1953, 100).  This must be so because it's a fuzzy concept with fuzzy boundaries.  In an Addendum to Jerry Coyne's blog post (noted above), Greg Mayer argues that this shows that Wilson was not a racist, because in rejecting the concept of subspecies, he rejected the concept of race.  "Roughly speaking, Wilson didn't believe there were races."  And, indeed, this is what many biologists have said in attacking scientific racism--race is a cultural construction that has no biological reality.

But Wilson does not really deny the biological reality of races or subspecies.  Insofar as the subspecies concept has fuzzy boundaries, it will always be to some extent "subjective and arbitrary," which is evident in the endless debates among taxonomists about how exactly to draw the boundaries.  But then every concept has fuzzy boundaries, more or less, and therefore is to some extent "subjective and arbitrary."  This is easy to see by going to any dictionary and looking at the many different definitions for the same word.  Yes, the subspecies concept is difficult to define, but then every concept is difficult to define.  If dividing between two racial categories allows us to make accurate predictions about each, then those racial categories are real, even when the difference between them is very small and fuzzy.  This is just as true for dividing between species.  The genetic differences on average between humans and chimpanzees is very small.  But no one would say that the distinction between humans and chimpanzees is meaningless.  Similarly, there are more genetic differences within breeds of dog that between the breeds; but no one would say that the differences between a Great Dane and a Chihuahua are meaningless.

When Wilson's 1953 subspecies article was reprinted in his 2006 book Nature Revealed: Selected Writings, 1949-2006, he added prefatory comments on the article, in which he wrote:  "Looking back now, I believe Brown and I overreached in our recommendations on classification.  There are populations that are both isolated, as on islands, and possess enough concordant traits to qualify as objective geographic units, and there are advantages to giving them formal trinomens.  Some of these populations are proving to be distinct species different enough so that even if they were contiguous, no interbreeding would occur, but others deserve denotation as objectively definable subspecies" (354).  So now he clearly recognizes "objectively definable subspecies," which must include human races.

He also observes, however, that human races are difficult to define; and so physical anthropologists in the 1950s "varied wildly in their definition of human races and hence their count of the number of races existing in the human species" (353).  This is still true today.

Rushton identified only three human races--Orientals, Whites, and Blacks.  But he admitted that since the races can and do interbreed, many if not most people are of mixed race.  American Blacks, for example, on average have around 25% European genes (2000, 18, 50, 54, 59, 66-68, 93).  He conceded, therefore, that "to a certain extent all the races blend into each other."  But still most people can be identified with one race or another.  And we can say that a Black is anyone most of whose ancestors were born in sub-Saharan Africa, a White is anyone most of whose ancestors were born in Europe, and an Oriental is anyone most of whose ancestors were born in East Asia (2000, 93).

Rushton cited the work of Luigi Cavalli-Sforza and his colleagues in The History and Geography of Human Genes (1994), who classified humans into races based on genetic polymorphisms (Rushton 2000, 85-89).  A genetic polymorphism is a gene that can be composed of alleles in different forms.  Cavalli-Sforza took polymorphic genes for blood groups, blood proteins, lymphocite antigens, and immunoglobins and calculated the different allele frequencies in populations around the world.  He then used factor analysis to see the genetic similarity of these allele frequencies to calculate the genetic differences between each population and every other population.  He could then calculate a genetic linkage tree that grouped the populations into racial clusters.  Rushton does not tell his reader, however, that instead of finding Rushton's three races, Cavalli-Sforza found ten:

1. Bushmen and Pygmies

2. Sub-Saharan Africans

3. South Asians and North Africans

4. Europeans

5. Northeast Asians

6. Arctic Peoples

7. Native American Indians

8. Southeast Asians

9. Pacific Islanders

10. Australian Aborigines and the Aboriginal New Guineans

These ten races don't fall neatly into the three-leveled pattern of Rushton's theory.

Wilson did not, as far as I know, try to distinguish all the human races.  In On Human Nature, he said: "most scientists have long recognized that it is a futile exercise to try to define discrete human races.  Such entities do not in fact exist" (48).  This passage has been quoted by those wanting to defend Wilson against the charge of racism by arguing that he denied that race had any biological reality.

But immediately after this passage, Wilson cited some research by psychologist Daniel Freedman that showed evidence for "geographical variation . . . in the genetic basis of social behavior" and "marked racial differences" in Asians, Caucasians, and Native American Indians (Wilson 1978, 48-50; 1980, 274).  Studying American newborn infants, Freedman detected "significant average differences in locomotion, posture, muscular tone of various parts of the body, and emotional response that cannot reasonably be explained as the result of training or even conditioning within the womb."  Chinese-American newborns tend to be more quiescent than Caucasian-American infants, and Navaho infants tend to be even more quiescent than the Chinese infants.  Since this cannot be explained as resulting from cultural learning, this must show genetic differences between Asians, Caucasians, and Native Americans.

Wilson observes:

"Given that humankind is a biological species, it should come as no shock to find that populations are to some extent genetically diverse in the physical and mental properties underlying social behavior.  A discovery of this nature does not vitiate the ideals of Western civilization.  We are not compelled to believe in biological uniformity in order to affirm human freedom and dignity.  The sociologist Marvin Bressler has expressed this idea with precision: 'An ideology that tacitly appeals to biological equality as a condition for human emancipation corrupts the idea of freedom.  Moreover, it encourages decent men to tremble at the prospect of 'inconvenient' findings that may emerge in future scientific research.  This unseemly anti-intellectualism is doubly degrading because it is probably unnecessary.'"

"I will go further and suggest that hope and pride and not despair are the ultimate legacy of genetic diversity, because we are a single species, not two or more, one great breeding system through which genes flow and mix in each generation.  Because of that flux, mankind viewed over many generations shares a single human nature within which relatively minor hereditary influences recycle through ever changing patterns, between the sexes and across families and entire populations" (50).

Wilson quoted this last paragraph in a letter to Nature in 1981, in which he defended himself against the charge of promoting racism.  "To keep the record straight," he wrote in the letter, "I am happy to point out that no justification for racism is to be found in the truly scientific study of the biological basis of social behaviour."  But notice that saying that there is no scientific justification for racism is compatible with saying that there is scientific justification for the biological reality of race.  A biological science of racial differences does not justify the racist xenophobia that denigrates or degrades those who belong to a race different from one's own.

Genetic differences in the average propensities and traits of the human races is compatible with the Lockean liberal principle of equal liberty.  Lockean equality means not that all people are identical--in intelligence or in many other respects--but that all people are similar in resisting exploitation by others, so that no human being is good enough to govern any other human being without that person's consent.  Equal liberty requires not equality of outcome, but equality of opportunity in the pursuit of happiness.  In a society of equal liberty, those individuals who are naturally more intelligent or talented than others will reap the benefits of those superior traits, but those superior individuals will have no right to exploit those of lesser abilities.  In such a society, everyone can find valued places for themselves.

I have argued for this in previous posts: here, here, here, here, here, here, here, here, here, and here.

REFERENCES

Borrello, Mark, and David Sepkoski. 2022. "Ideology as Biology." The New York Review of Books, February 5.

Cavalli-Sforza, Luigi, P. Menozzi, and A. Piazza. 1994. The History and Geography of Human Genes. Princeton, NJ: Princeton University Press.

Farina, Stacy, and Matthew Gibbons. 2022. "'The Last Refuge of Scoundrels': New Evidence of E. O. Wilson's Intimacy with Scientific Racism.'"  Science for the People, February 1.

Fischer, Anne, Joshua Pollack, Olaf Thalmann, Birgit Nickel, and Svante Paabo. 2006. "Demographic History and Genetic Differentiation in Apes." Current Biology 16: 1133-1138.

MacArthur, R. H., and E. O. Wilson. 1967. The Theory of Island Biogeography. Princeton, NJ: Princeton University Press.

Rushton, J. Philippe. 1992. "Evolutionary Biology and Heritable Traits (With Reference to Oriental-White-Black Differences): The 1989 AAAS Paper." Psychological Reports 71: 811-21.

_____. 1997. Race, Evolution, and Behavior: A Life History Perspective. 2nd ed. New Brunswick, NJ: Transaction Publishing.

_____. 2000. Race, Evolution, and Behavior: A Life History Perspective. 2nd Special Abridged Edition. Port Huron, MI: Charles Darwin Research Institute.

Stanford, Craig. 2018. The New Chimpanzee: A Twenty-First-Century Portrait of Our Closest Kin. Cambridge, MA: Harvard University Press.

Wilson, Edward O., and W. L. Brown. 1953. "The Subspecies Concept and Its Taxonomic Application." Systematic Zoology 2: 97-111.

Wilson, Edward O.  1975. Sociobiology: The New Synthesis. Cambridge, MA: Harvard University Press.

_____. 1978. On Human Nature. Cambridge, MA:  Harvard University Press.

_____. 1980. Sociobiology: The New Synthesis. Abridged edition. Cambridge, MA: Harvard University Press.

_____. 1987. "Genes and Racism." Nature 289 (February 19): 627.

_____. 2000. Sociobiology: The New Synthesis. 25th anniversary edition. Cambridge, MA: Harvard University Press.

_____. 2006. Nature Revealed: Selected Writings, 1949-2006. Baltimore, MD: Johns Hopkins University Press.