Tags: hominin evolution, brain size, Chauvet Cave, Paleolithic art, shamanism, darkness, cave paintings, Ardipithecus, Australopithecus, Homo habilis, Homo sapiens, brain volume, cranial capacity
Hominin brain size grew from roughly 350 cc (Ardipithecus) to 1400 cc (modern humans) over several million years, with the most dramatic expansion occurring in the last two million years. This biological growth correlates with increasingly sophisticated behaviour: tool use, language, social complexity, and symbolic art. The Chauvet Cave paintings (30,000+ years old) offer early evidence of inner mental life, likely linked to shamanic practices conducted in total darkness.
Chauvet Cave
Discovered in 1994 in France, it contains the oldest known Paleolithic art, dating back more than 30,000 years. Drawings depict animals and fusions of forms deep within limestone caves.
Paleolithic art
Drawings, engravings, and paintings created during the Old Stone Age. Often found in deep, dark cave environments and thought to reflect symbolic or spiritual practices.
Shamanism
A practice in which healers (shamans) access altered states of consciousness for knowledge and spiritual connection. In the course context, shamans used sensory deprivation (darkness) to facilitate these states.
Darkness as hallucinogen
The course frames total darkness as a tool for inner exploration. In the absence of external visual stimuli, the mind generates rich internal imagery, a form of hallucination that Paleolithic humans may have deliberately sought out.
Ardipithecus ramidus
The oldest hominin genus discussed in the course, dating to approximately 4.4 million years ago, with a brain volume of roughly 350 cc (comparable to a modern chimpanzee).
Australopithecus
A hominin genus spanning roughly 1 to 4 million years ago, with brain volumes around 500 cc (e.g., A. africanus).
Homo habilis
An early member of the genus Homo, dating from about 1.4 to 2.3 million years ago, with a brain volume of approximately 650 cc. The name means "handy man," reflecting association with early stone tools.
Homo sapiens
Modern humans, with a brain volume of approximately 1400 cc.
Cranial capacity (cc)
A measure of brain volume in cubic centimetres, used to track brain-size changes across the hominin lineage.
Conspecific
A member of the same species. In course context, the intentional killing of a conspecific (depicted in 2001: A Space Odyssey) marks a behavioural milestone in human evolution.
Ardipithecus ramidus: ~4.4 million years ago, ~350 cc
Australopithecus (e.g., A. africanus): ~1–4 million years ago, ~500 cc
Homo habilis: ~1.4–2.3 million years ago, ~650 cc
Homo sapiens: present, ~1400 cc
The most rapid expansion in brain volume occurred in the last 2 million years, coinciding with the emergence and diversification of the genus Homo.
Larger brains correlate with nuanced social interaction, complex problem-solving, language, and mathematical reasoning.
These cognitive capacities eventually produced elaborate explanatory frameworks (modern science) and cultural artefacts (cave art, tools).
The course highlights a "deadly marriage" between intelligence and primal violence: the same brain that creates art also enables intentional killing of conspecifics.
The paintings are found deep within the cave, far from daylight.
Depictions include animals and hybrid or fused forms, suggesting symbolic or spiritual meaning rather than simple record-keeping.
The location in total darkness is significant: it implies the art was created in, or inspired by, altered states of consciousness.
Total darkness removes external visual input, prompting the brain to generate its own imagery (a natural form of hallucination).
Shamans, described as healers and respected community members, were skilled at entering these states to access knowledge and communicate with nature or spirits.
The cave environment provided a stable, cross-generational space for these rituals.
Cave paintings likely represent the visions and connections experienced during these practices.
The film depicts a hominin discovering that a bone can be used as a weapon to kill a conspecific.
This moment is framed as a critical behavioural milestone, representing the emergence of intentional tool-based violence alongside higher cognition.
⚠️ Know the specific brain volumes for each genus (350, 500, 650, 1400 cc). These numbers appear directly in multiple-choice and essay questions.
⚠️ "Darkness as hallucinogen" is a distinctive course concept. The exam tests whether you understand that darkness facilitated inner exploration, not just protection from predators or food storage.
⚠️ The 2001: A Space Odyssey reference is specifically about killing a conspecific with a tool, not about fire, migration, or cave painting.
⚠️ Ardipithecus (4.4 million years ago) is the oldest genus on the course timeline, not Australopithecus.
Q: What was the likely function of deep cave darkness for Paleolithic humans?
A: It acted as a natural hallucinogen or aid to inner exploration. The absence of visual stimuli allowed rich internal mental imagery, which shamans used for spiritual practices and connection with nature.
Q: List the major hominin genera in chronological order, with approximate brain volumes.
A: Ardipithecus (~4.4 mya, ~350 cc), Australopithecus (~1–4 mya, ~500 cc), Homo habilis (~1.4–2.3 mya, ~650 cc), Homo sapiens (present, ~1400 cc).
Q: What behavioural milestone does 2001: A Space Odyssey depict?
A: The willful, intentional killing of a conspecific using a bone as a tool or weapon.
Q: Why do the Chauvet Cave paintings likely reflect shamanic practices rather than simple record-keeping?
A: They are located deep in total darkness (not near cave entrances), depict fusions of forms suggestive of altered states, and align with the use of sensory deprivation to induce hallucination and spiritual connection.
Q: What is the "deadly marriage" referred to in the course?
A: The combination of advanced intelligence and primal violence in the same species, allowing humans to create art and culture while also being capable of intentional killing.
hominin evolution, brain size evolution, cranial capacity, Chauvet Cave, Paleolithic cave art, shamanism, sensory deprivation, darkness as hallucinogen, Ardipithecus ramidus, Australopithecus africanus, Homo habilis, Homo sapiens, conspecific killing, 2001 A Space Odyssey, Kubrick, tool use evolution, brain volume timeline, MCB C61, Brain-Mind Odyssey