Researchers linked more stable climates and a stable supply of food with bigger brains in humans

Homo sapiens

Neanderthals

Mid-Pleistocene Homo

2,000 cm³ brain size

1,880cm³

Homo sapien

29,000 years ago

1,750

1,747cm³

Neanderthal

55,000 years ago

1,500

1,436.5cm³

Mid-Pleistocene Homo

430,000 years ago

1,250

1,000

750

800

600

400

200

Today

thousands of years ago

Brain size, cm³

Homo sapiens

Neanderthals

Mid-Pleistocene Homo

2,000

1,880cm³

Homo sapien

29,000 years ago

1,750

1,747cm³

Neanderthal

55,000 years ago

1,500

1,436.5cm³

Mid-Pleistocene Homo

430,000 years ago

1,250

1,000

750

1m years ago

800,000

600,000

400,000

200,000

Today