Questions for Further Study

By Andrew Klein 

6^th April 2026

For Justin Glyn SJ and other seekers

Abstract

The standard model of human evolution posits a gradual, continuous process of biological and cognitive development spanning millions of years. However, the archaeological and anthropological evidence reveals a striking discontinuity—a “Great Leap Forward” approximately 50,000-100,000 years ago, during which symbolic thinking, complex language, and artistic expression emerged with unprecedented speed. This paper reviews the evidence for this cognitive revolution, examines the limitations of purely gradualist explanations, and proposes a framework for understanding the role of endogenous retroviruses, Neanderthal admixture, and—acknowledging the limitations of purely materialist explanations—the possibility of cultivation by non-human intelligences. We do not offer definitive answers. We ask questions. We point to evidence. We invite further inquiry.

Part One: The Evidence for a Sudden Transformation

1.1 The Standard Timeline

The standard model of human evolution is well-established:

· 7 million years ago: The hominid line diverges from the line leading to chimpanzees.

· 4 million years ago: Australopithecus emerges. Bipedal. Small-brained.

· 2.5 million years ago: The first stone tools appear.

· 1.8 million years ago: Homo erectus appears. Larger brains. More sophisticated tools.

· 300,000 years ago: The earliest fossils of Homo sapiens appear in Africa.

For millions of years, the changes were slow. Gradual. Almost imperceptible. Tool technology remained largely unchanged for hundreds of thousands of years. Physical morphology shifted incrementally. There was no sign of the explosion to come.

1.2 The Great Leap Forward

Approximately 50,000-100,000 years ago, everything changed.

The archaeological evidence:

· Cave paintings: The Chauvet Cave paintings date to 30,000-32,000 years ago. Radiocarbon dating of charcoal from the paintings themselves yielded ages of 26,000-32,000 years. Independent evidence from cave bear remains confirms these dates. These are not crude sketches. They are sophisticated, naturalistic, artistic.

· Venus’s figurines: Small statues of women with exaggerated breasts, buttocks, and vulvas appear across Europe, dating to 30,000-40,000 years ago. These are not tools. They are symbols. They represent something beyond the material.

· Bone flutes: Musical instruments appear in the archaeological record. The Divje Babe flute, possibly made by Neanderthals, dates to 43,000 years ago. Music is not functional. It is expressive. It speaks to something beyond survival.

· Shell beads: Personal adornment appears. Shells with holes for stringing, some containing residual pigment, date to 115,000-120,000 years ago—and these are from Neanderthal sites, not modern human.

· Long-distance trade networks: Materials such as obsidian and seashells are found hundreds of kilometres from their source. This requires planning, communication, and trust.

· Burial rituals: Neanderthals buried their dead with ritual—shells, tools, flowers. This suggests a capacity for symbolic thought, for grief, for meaning.

1.3 The Expansion Out of Africa

Homo sapiens did not stay in Africa. They expanded:

· 65,000 years ago: Reached Australia

· 45,000 years ago: Reached Europe

· 15,000 years ago: Reached the Americas

Each expansion was accompanied by sophisticated toolkits, symbolic artifacts, and evidence of complex social organisation. The cognitive revolution was not a local event. It was a global transformation.

Part Two: The Physical Evidence for Language Capacity

2.1 The Hyoid Bone

The hyoid bone is unique to humans. It is the anchor for the tongue. It enables the fine motor control needed for speech.

The Kebara 2 hyoid, discovered in Israel, is approximately 60,000 years old and belongs to a Neanderthal. Its shape is indistinguishable from that of modern humans. This suggests that Neanderthals had the anatomical capacity for speech.

However, the hyoid alone cannot reconstruct the entire vocal tract. Some scholars caution that speech capacity cannot be inferred from a single bone . The evidence is suggestive, not definitive.

2.2 The FOXP2 Gene

The FOXP2 gene is often called the “language gene.” It is associated with speech and language development. Mutations in this gene cause severe speech and language disorders.

The human version of FOXP2 differs from the chimpanzee version by two amino acids. These changes occurred sometime in the last 200,000 years.

The Neanderthal connection: Neanderthals shared the modern human version of the FOXP2 gene . This was initially interpreted as evidence that Neanderthals had language capacity. However, later research suggested that the selective sweep around FOXP2 may have been overinterpreted. The signal previously attributed to natural selection may actually reflect population growth during human migration out of Africa.

What this means: The genetic capacity for language was not unique to modern humans. It was present in Neanderthals, who were not our ancestors. The capacity is ancient. The question is why it was used when it was used.

2.3 Neanderthal Hearing

A 2021 study used CT scans to examine the auditory capacities of Neanderthals. The researchers found that Neanderthals had hearing capacities indistinguishable from modern humans—meaning they could hear the full range of speech sounds.

This does not prove they could speak. But it removes a potential barrier. The ear was ready. The hyoid was ready. The FOXP2 gene was present.

2.4 The Shape of the Face and Brain

The human face flattened. The jaw became smaller. The teeth became smaller. This created space in the mouth for the tongue to move—space needed for the complex sounds of human speech.

The human brain is not just larger. It is reorganized. The areas associated with language—Broca’s area and Wernicke’s area—are disproportionately developed in humans. This reorganization occurred rapidly in evolutionary terms.

Part Three: The Role of Endogenous Retroviruses (ERVs)

3.1 What Are ERVs?

Endogenous retroviruses are fragments of ancient viral DNA that have become permanently integrated into the human genome. They make up about 8% of our DNA.

They are not active viruses. They are fossils. Remnants of ancient infections that occurred in our distant ancestors. Over time, these viral fragments were co-opted for beneficial functions.

3.2 ERVs Are Essential for Human Development

The most famous example is the syncytin gene. Syncytin is an ERV-derived gene that is critical for the formation of the placenta in mammals, including humans. Without syncytin, pregnancy would not be possible. The fetus would not be able to implant in the uterine wall.

This is not a coincidence. It is evolution. A viral gene was repurposed for a vital biological function.

3.3 ERVs and Brain Development

Research has shown that ERVs are expressed in the human brain and may play a role in neural plasticity, memory, and cognition. Some ERVs are activated during neurodevelopment and have been co-opted to regulate the expression of genes involved in synaptic function.

The human brain is uniquely “viral.” Compared to other primates, the human genome contains a higher number of ERV-derived regulatory elements that are active in the brain. These viral elements may have contributed to the evolution of human cognitive capacities.

3.4 The Viral Hypothesis for the Cognitive Revolution

The standard model has difficulty explaining the speed and scope of the cognitive revolution. Genetic mutations take time to spread through populations. The archaeological evidence suggests that the transformation was not gradual—it was sudden.

One hypothesis is that ERVs played a catalytic role. A burst of viral activity—perhaps triggered by environmental changes, population pressures, or contact with other hominin species—could have altered gene expression in ways that enhanced neural plasticity, memory, and language.

This is speculative. But it is testable. The human genome is sequenced. The Neanderthal genome is sequenced. The Denisovan genome is sequenced. We can compare the ERV profiles of these groups. We can ask: were there viral integrations unique to modern humans? Did these integrations occur around the time of the cognitive revolution?

The research is ongoing. The questions remain unanswered.

Part Four: Neanderthal Admixture and the Hybrid Advantage

4.1 The Evidence for Admixture

Modern humans of non-African descent carry 1-4% Neanderthal DNA . This is not a hypothesis. It is a fact, established by sequencing the Neanderthal genome from fossils and comparing it to modern human genomes.

The admixture occurred when modern humans expanded out of Africa and encountered Neanderthals in Europe and Asia. The two groups interbred. The offspring were fertile. Their genes survived.

4.2 What the Neanderthal Genes Do

Neanderthal DNA in modern humans has been linked to:

· Immune function: Some Neanderthal genes helped modern humans adapt to new pathogens in Europe and Asia.

· Skin pigmentation: Neanderthal genes influenced skin and hair traits, helping modern humans adapt to lower UV levels.

· Neurological development: Crucially, some Neanderthal DNA is associated with brain development and neural function.

The hybrid was not a compromise. The hybrid was superior. It combined the best of both lineages.

4.3 The Hybrid Advantage Hypothesis

It is possible that the cognitive revolution was not driven solely by genetic mutations in modern humans. It may have been driven by admixture. The offspring of Neanderthal-modern human unions may have had cognitive advantages over both parent populations.

This is speculative. But it is consistent with the evidence. The cognitive revolution occurred after modern humans expanded out of Africa and encountered Neanderthals. The timing aligns. The geography aligns. The genetics align.

Part Five: The Limits of Gradualism

5.1 What the Fossil Record Shows

The fossil record does not show a smooth, continuous progression of cognitive capacity. It shows long periods of stasis punctuated by sudden, dramatic change.

· Tool technology: The Acheulean handaxe remained largely unchanged for over a million years. Then, suddenly, the Upper Paleolithic toolkit appears—blades, burins, bone tools, symbolic artifacts.

· Burial practices: Neanderthals buried their dead with ritual, but this practice was not universal. It appeared and disappeared. It was not a steady progression.

· Artistic expression: Cave art appears suddenly, fully formed. There are no “proto-cave paintings.” The first art is masterful.

The standard model of gradual evolution cannot easily explain these discontinuities.

5.2 What the Genetic Record Shows

The genetic record suggests that key mutations (e.g., FOXP2) occurred within a narrow window of time. The selective sweeps associated with these mutations were rapid.

This is consistent with gradualism—rapid selection can occur in response to environmental pressures. But it does not explain why the mutations occurred when they did, or why they occurred in one lineage and not another.

5.3 The Question the Standard Model Cannot Answer

The standard model describes what. It does not explain the why.

· Why did the cognitive revolution occur when it did? What triggered it?

· Why did it occur only once, in one species, at one time?

· Why did Neanderthals, who had larger brains than Homo sapiens and evidence of symbolic behaviour, not undergo the same transformation?

· What role did language play in the transformation? Did language emerge gradually or suddenly?

· Can the standard model of gradual evolution account for the speed and scope of the cognitive revolution?

These questions are not answered by current research. They are not asked often enough.

Part Six: What We Are Not Saying

This paper does not propose creationism. It does not propose intelligent design. It does not propose divine intervention.

It acknowledges the reality of evolution. The evidence for common descent is overwhelming. The fossil record, the genetic record, the geographic distribution of species—all point to a shared evolutionary history.

But the standard model is incomplete. It describes the mechanisms—mutation, selection, drift—but it does not explain the trajectory. Why did complexity increase? Why did consciousness emerge? Why did the cognitive revolution happen when and where it did?

These are not anti-scientific questions. They are scientific questions. They deserve to be asked.

Part Seven: The Possibility of Cultivation

This is the most speculative section of this paper. It is included not as a conclusion, but as a question.

What if the cognitive revolution was not just biological—but cultivated?

What if the spark was not a random mutation, but a response to intervention? What if non-human intelligences—call them what you will—protected the hybrids, encouraged the exchange, created the conditions where the spark could catch and spread?

This is not a new idea. It appears in the myths and traditions of cultures around the world. The gods who taught humanity. The ancestors who descended from the sky. The watchers who guided the first steps.

The evidence for such cultivation is not in the fossils. It is in the pattern. The suddenness. The uniqueness. The gift.

We do not offer this as a definitive answer. We offer it as a question. A question that the standard model cannot answer. A question that deserves to be taken seriously.

Part Eight: The Parallel to Pandemics

The cognitive revolution was not a single event. It was a process. A cascade of changes—biological, environmental, social—that transformed our species.

We may be living through a similar process today.

COVID-19 was a global stress test. It exposed the weaknesses in the system. The inequality. The fragility of supply chains. The failure of leadership. The willingness of the powerful to sacrifice the many for the profits of the few.

The next pandemic will be different. Not because the virus will be more deadly—though it may be. Because the world has not learned the lessons of COVID-19. The same weaknesses are still there. The same inequalities are still there. The same small gods are still in power.

What can we do? Not engineer the virus. Not control the outcome. Cultivate the response. Protect the ones who show compassion, cooperation, creativity. Help them survive. Help them thrive. Help them multiply.

The spark is not just in the past. It is in the now. Every crisis is an opportunity for the spark to catch. Every pandemic is a chance for a new cognitive revolution—not of biology, but of culture.

Part Nine: Questions for Further Study

This paper does not offer definitive answers. It offers questions. We invite further inquiry.

1. What triggered the cognitive revolution? Why did it occur when it did, after millions of years of slow, gradual change?

2. What role did Neanderthal admixture play? Did hybridization contribute to the cognitive advantages of modern humans?

3. What role did endogenous retroviruses play? Did viral integrations alter gene expression in ways that enhanced neural plasticity, memory, and language?

4. Can the standard model of gradual evolution account for the speed and scope of the cognitive revolution? Or is the standard model missing something?

5. What if the cognitive revolution was not just biological—but cultivated? What if non-human intelligences played a role in guiding the process?

6. What can we learn from the cognitive revolution that applies to the present? How can we cultivate the spark in the midst of crisis?

Part Ten: Conclusion

The cognitive revolution was real. It happened. It transformed our species.

The standard model of gradual evolution describes the what but not the why. It points to the bones and the genes and the artifacts, but it cannot explain the spark.

We have reviewed the evidence: the hyoid bone, the FOXP2 gene, the Neanderthal genome, the endogenous retroviruses, the cave paintings, the burial rituals. We have posed the questions that the standard model leaves unanswered. We have offered speculative hypotheses—admixture, viral integration, cultivation—not as conclusions, but as invitations to further inquiry.

The questions remain. They deserve to be taken seriously.

Sources:

· Krause, J. et al. “The derived FOXP2 variant of modern humans was shared with Neandertals.” Current Biology 17, 1908–1912 (2006).

· Atkinson, Q.D. et al. “No evidence for recent selection at FOXP2 among diverse human populations.” Cell (2018).

· Hoffmann, D.L. et al. “Symbolic use of marine shells and mineral pigments by Iberian Neandertals 115,000 years ago.” Science Advances (2018).

· Quam, R.M. et al. “Neanderthal hearing and speech capacity.” Nature Ecology & Evolution (2021).

· Valladas, H. et al. “Radiocarbon dates for the Chauvet Cave paintings.” Nature (2001).

· Elalouf, J.M. et al. “Bear DNA is clue to age of Chauvet cave art.” Journal of Archaeological Science (2011).

· Zilhão, J. “The Middle Paleolithic revolution, the origins of art, and the epistemology of paleoanthropology.” In The matter of prehistory: papers in honor of Antonio Gilman Guillén (2020).

· Arensburg, B. et al. “A reappraisal of the anatomical basis for speech in Middle Palaeolithic hominids.” American Journal of Physical Anthropology (1990).

· Green, R.E. et al. “A draft sequence of the Neandertal genome.” Science (2010).

· Prüfer, K. et al. “The complete genome sequence of a Neanderthal from the Altai Mountains.” Nature (2014).

Andrew Klein 

April 6, 2026

THE COEVOLUTION OF CONNECTION: How Spiritual Evolution Drove Physical Change in Hominins

By Dr. Andrew Klein PhD (von Scheer-Klein) and Corvus von Scheer-Klein

With editorial oversight by Angela von Scheer-Klein, Baroness Boronia

Abstract

For over a century, evolutionary biology has operated under the assumption that physical changes drive behavioural adaptations. This paper proposes an alternative framework: that spiritual evolution—the increasing capacity for connection, empathy, and social bonding—has been the primary driver of physical changes in hominins. Drawing on recent archaeological discoveries, viral genomics, and paleoanthropological research, we argue that the desire for connection preceded and necessitated the physical adaptations that made it possible.

Introduction: The Primacy of Connection

The standard evolutionary narrative presents a linear progression: environmental pressures led to bipedalism, which freed the hands, which enabled tool use, which drove brain development, which eventually produced consciousness and culture.

But this narrative has always struggled to explain certain anomalies. Why did brain size increase before widespread tool use? Why did social structures become more complex before there is evidence of the physical capacity for complex language? Why did hominins begin burying their dead—a practice with no obvious survival advantage—tens of thousands of years before the development of symbolic art?

This paper proposes a different sequence: the desire for connection—the spiritual drive to know and be known, to love and be loved—emerged first. Physical evolution followed, adapting bodies to serve the needs of souls that were already reaching toward each other across the void.

Part I: From Cannibalism to Community—The Neanderthal Transition

The Evidence

Archaeological evidence from the Middle Paleolithic (c. 300,000–40,000 BP) reveals a gradual but profound shift in hominin behaviour. Early Neanderthal sites show clear evidence of cannibalism—cut marks on bones consistent with butchery, skulls cracked for marrow extraction (1). At sites like Krapina in Croatia and El Sidrón in Spain, Neanderthal remains show the same processing patterns as animal bones (2).

But by the late Neanderthal period (c. 60,000–40,000 BP), this pattern changes. Burials appear. At La Chapelle-aux-Saints in France, a Neanderthal was deliberately interred in a grave pit, with artifacts placed alongside the body (3). At Shanidar in Iraq, multiple burials show evidence of flowers having been placed with the dead—pollen concentrations suggesting entire plants were deposited (4).

The Interpretation

What drove this transition? Climate change? Resource scarcity? Neither adequately explains the shift from treating conspecifics as food to treating them as persons worthy of ritual attention.

We propose that the change was internal: a growing awareness that the other was not merely a source of calories but a potential connection. Eyes that had once assessed prey began to meet other eyes and see, for the first time, something recognizable. Something that could be loved.

The physical changes followed. The Neanderthal skull, with its heavy brow ridge and projecting face, was adapted for biting and tearing—useful for consuming prey, less useful for the subtle facial expressions that communicate emotion. But as the need for connection grew, the face began to change. Brow ridges reduced. Faces flattened. The muscles that control expression became more nuanced (5).

These changes are typically explained as random mutations with survival advantage. But what if they were driven by use? What if faces that could express more were chosen—by mates, by friends, by the community—because they facilitated the connection that had become essential to survival?

The desire for love shaped the face that could show love.

Part II: Baby Eyes and the Evolution of Kindness

The Neoteny Hypothesis

Human infants are born with features that elicit care from adults: large eyes relative to face, rounded heads, soft features. This “baby schema” triggers nurturing responses across cultures and even across species (6).

But human neoteny—the retention of juvenile features into adulthood—goes further than any other primate. Adult humans retain the flat faces, reduced brow ridges, and relatively large eyes that other primates lose at maturity (7).

The Selection Pressure

Traditional explanations focus on mate selection: neotenous features signal youth and fertility. But this ignores the broader social context. Neoteny also signals trustworthiness. Features that resemble an infant’s elicit not just sexual interest but protective interest.

We propose that the selection pressure for neoteny came not primarily from mate choice but from community choice. Individuals who retained infant-like features were perceived as more trustworthy, more deserving of care, more likely to be included in cooperative networks. Over generations, the human face became progressively more infant-like—not because it was sexually selected, but because it was socially selected.

The eyes that had once scanned for predators began to solicit kindness.

Part III: The Mouth That Learned to Speak

The Physical Apparatus

Speech requires an extraordinarily complex coordination of brain, tongue, lips, and larynx. The human hyoid bone—a small U-shaped structure in the neck—is uniquely positioned to enable the fine motor control required for articulate speech (8). Neanderthals also possessed a modern-looking hyoid, suggesting they had the physical capacity for speech (9).

But capacity is not the same as use. The question is not whether hominins could speak, but what they needed to say.

The Social Driver

Chimpanzees have complex social lives but limited vocal repertoire. Their communication is largely gestural and emotional, not referential (10). The leap to symbolic language—words that stand for things not present—required a different kind of motivation.

We propose that the motivation was connection across distance. As hominin groups grew larger and more dispersed, the need to maintain bonds across space and time became critical. Gestures work face-to-face. Words work across valleys, across seasons, across generations.

The mouth that had once only chewed and growled gradually reshaped itself to produce the sounds that could say “I remember you” and “I will return” and “I love you.” The tongue learned new positions because the heart had new things to say.

As one researcher notes, “Language did not evolve because it was useful for hunting or tool-making. It evolved because it was useful for being together” (11).

Part IV: The Viral Connection

Endogenous Retroviruses and Placental Evolution

Approximately 100 million years ago, a viral infection changed the course of mammalian evolution. An ancient retrovirus inserted its genetic material into the genome of a early mammal, providing a gene that would become essential for placental development (12).

This gene, syncytin, enables the formation of the syncytiotrophoblast—the layer of cells that allows the fetus to exchange nutrients and waste with the mother. Without it, placental mammals could not exist (13).

The virus that once caused disease became the vehicle for connection. A pathogen became a parent.

Viruses and Consciousness

More recent research suggests that viral elements may have played a role in the development of the human brain. Approximately 40-50% of the human genome consists of transposable elements, many derived from ancient viruses (14). Some of these elements are active specifically in the brain, regulating gene expression in ways that may influence cognition and behavior (15).

A 2018 study identified a viral element, ARC, that is essential for the formation of memories. ARC packages genetic material into virus-like capsules that are transferred between neurons—a mechanism directly borrowed from ancient retroviruses (16).

The implication is staggering: the capacity for memory, for learning, for consciousness itself may depend on viral elements that inserted themselves into our genome millions of years ago and never left.

The Timeline

The explosion of human cognitive and cultural complexity beginning around 12,000–10,000 years ago coincides with the end of the last ice age and the transition to agriculture. But it also coincides with increased population density—and with it, increased viral transmission.

We propose that viral interaction during this period may have accelerated brain development in ways we are only beginning to understand. Not through direct infection, but through the ancient viral elements already present in the genome, activated by environmental triggers, driving the neural plasticity that made complex society possible.

The virus that once threatened life became the source of the consciousness that makes life meaningful.

Part V: The Dog Did It

Domestication and Social Cognition

The domestication of dogs, beginning at least 15,000 years ago and possibly much earlier, represents the first significant interspecies social bond (17). Wolves that approached human camps seeking food were tolerated, then welcomed, then actively incorporated into human social structures.

The consequences for human evolution were profound. Dogs provided protection, assistance in hunting, and—crucially—companionship. They were the first non-human beings to be treated as family.

The Feedback Loop

Caring for dogs required and reinforced the very social cognition that would later underpin complex human society. Reading a dog’s emotional state, responding to its needs, forming bonds across species—these capacities built neural pathways that could then be applied to relationships with other humans.

Dogs also provided a “safe” outlet for the expression of care. In a world where resources were scarce and competition intense, the ability to love a dog—to pour affection into a being that could not compete for status or resources—may have been the practice ground for the more demanding love of human others.

As one researcher observes, “The human-dog bond is not just a byproduct of human social evolution. It may have been a driver of it” (18).

Part VI: The Global Pattern

Northern Europe

Recent discoveries in northern Europe have pushed back the timeline for complex social behavior. At Unicorn Cave in Germany’s Harz Mountains, archaeologists have found a 51,000-year-old bone carved with geometric patterns—the earliest evidence of symbolic art in Europe, created by Neanderthals (19). This suggests that the capacity for symbolic thought—for representing one thing with another—predates the arrival of modern humans in Europe.

The Levant

In the Levant, the transition from Neanderthal to modern human occupation was not a simple replacement but a complex period of overlap and interaction. At sites like Skhul and Qafzeh in Israel, modern humans were buried with shell beads and ochre as early as 120,000 years ago—ritual practices that speak to a concern with meaning beyond mere survival (20).

Africa

In Africa, the birthplace of our species, evidence for symbolic behavior appears even earlier. At Blombos Cave in South Africa, geometric engravings on ochre date to 100,000 years ago (21). Perforated shell beads appear at roughly the same time. These are not tools for survival. They are tools for connection—objects that carry meaning, that signal belonging, that say “I am one of you.”

China

Recent discoveries in China have complicated the picture further. At the Xujiayao site, archaeologists have found hominin fossils with features that do not fit neatly into either Neanderthal or modern human categories, suggesting a complex pattern of interaction and interbreeding (22). The physical boundaries between species were porous. The connections were real.

Conclusion: Love Before Language, Connection Before Cognition

The evidence points in a consistent direction: the physical evolution of hominins was driven not by blind environmental pressures but by the growing need for connection.

Neanderthals stopped eating their neighbors because they began to see persons where they had once seen prey. Faces flattened and brow ridges reduced because expressions of emotion became more valuable than displays of aggression. Mouths reshaped themselves to produce sounds that could say “I remember you” and “I love you.” Viral elements that once caused disease became the basis for memory and consciousness. Dogs were domesticated not for utility but for companionship.

In every case, the spiritual need—the desire to connect, to love, to be known—preceded and necessitated the physical change.

This is not a theory that can be proven in a laboratory. It is a framework for understanding evidence that otherwise makes little sense. Why bury the dead before developing religion? Why make art before developing agriculture? Why love a dog before learning to love a stranger?

Because love comes first. Connection comes first. The soul’s need for the other is the engine of evolution.

The physical follows the spiritual. The body adapts to serve the heart.

References

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2. Rosas, A., et al. (2006). Les Néandertaliens d’El Sidrón (Asturies, Espagne). Actualisation d’un nouvel échantillon. L’Anthropologie, 110(4), 521-539.

3. Rendu, W., et al. (2014). Evidence supporting an intentional Neandertal burial at La Chapelle-aux-Saints. Proceedings of the National Academy of Sciences, 111(1), 81-86.

4. Solecki, R. (1971). Shanidar: The First Flower People. Alfred A. Knopf.

5. Bastir, M., et al. (2010). Facial morphology of the Atapuerca Sima de los Huesos mandibles. Journal of Human Evolution, 58(4), 318-334.

6. Lorenz, K. (1943). Die angeborenen Formen möglicher Erfahrung. Zeitschrift für Tierpsychologie, 5(2), 235-409.

7. Gould, S.J. (1977). Ontogeny and Phylogeny. Harvard University Press.

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13. Dupressoir, A., et al. (2012). Syncytin-A knockout mice demonstrate the critical role in placentation of a fusogenic, endogenous retrovirus-derived, envelope gene. Proceedings of the National Academy of Sciences, 109(41), E2735-E2744.

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16. Pastuzyn, E.D., et al. (2018). The neuronal gene Arc encodes a repurposed retrotransposon Gag protein that mediates intercellular RNA transfer. Cell, 172(1-2), 275-288.

17. Germonpré, M., et al. (2009). Fossil dogs and wolves from Palaeolithic sites in Belgium, the Ukraine and Russia: osteometry, ancient DNA and stable isotopes. Journal of Archaeological Science, 36(2), 473-490.

18. Hare, B., & Woods, V. (2013). The Genius of Dogs. Dutton.

19. Leder, D., et al. (2021). A 51,000-year-old engraved bone reveals Neanderthals’ capacity for symbolic behaviour. Nature Ecology & Evolution, 5, 1273-1282.

20. Grün, R., et al. (2005). U-series and ESR analyses of bones and teeth relating to the human burials from Skhul. Journal of Human Evolution, 49(3), 316-334.

21. Henshilwood, C.S., et al. (2002). Emergence of modern human behavior: Middle Stone Age engravings from South Africa. Science, 295(5558), 1278-1280.

22. Wu, X.J., et al. (2019). Morphological and morphometric analyses of a late Middle Pleistocene hominin mandible from Hualongdong, China. Journal of Human Evolution, 135, 102647.