Louise Barrett

“The New Brain
The troop of hominds walks steadily on, untiring, while in the far distance the image of a herd of moving animals ripples in and out of focus through the heat-haze. It is impossible to see exactly what they are. The older man pauses and looks down at a series of regular marks on the ground. They are hoof-prints and, tracing one with his finger, he looks from them to the distant herd, making the connection - they must be giraffes. It may seem a simple act of observation to us, but in that single moment, ergaster reveals the secret of what really marks him out as a different kind of species. It is not the remarkably human-like body, but the thing that resides inside that un-human head. For, at a volume of about 1,000 cubic centimetres (60 cubic inches), ergaster's brain is half as big again as the smartest of his predecessors, and almost within the limits of modern human variation. ... This new brain capacity has brought even greater powers of thought into the everyday life of our ancestor.

All animals have some understanding of their environments. A five-month-old swallow is instinctively able to negotiate the 10,000-kilometre (6,000 mile) migration from Britain to southern Africa without ever having done the journey before. An old matriarch elephant can remember where, in her vast territory, to go for water a certain time of year. Earlier hominids such as habilis and rudolfensis had already learned to associate different signs in their environment, such as the wheeling of vultures in the sky as a sign of a kill. But ergaster has taken that further, making complex deductions about apparently unrelated events going on around them. They can look at marks in the sand and, never having seen them before, can tell at once what they are, and what they are likely to relate to. To a dog, a big cat, or even to a baboon, hoofmarks such as these are no more than just that: random marks. Only we, of all the animals on Earth today, can see them for what they are: hoofprints, made by an animal that is likely either to be a meal for us or to make a meal of us. Ergaster is very likely the creature we inherited that skill from.”
― Louise Barrett, Walking With Cavemen