The Day We Learned To ThinkUnderstanding of humans' earliest past often comes from studying fossils. They tell us much of what we know about the people who lived before us.

There is one thing fossils cannot tell us; at what point did we stop living day-to-day and start to think symbolically, to represent ideas about our environment and how we could change it?

At a dig in South Africa the discovery of a small piece of ochre pigment, 70,000 years old, has raised some very interesting questions. Anatomically modern humans (Homo sapiens) emerged in Africa roughly 100,000 years ago.

We know from fossil evidence that Homo sapiens replaced other hominids around them and moved out of Africa into Asia and the Middle East, reaching Europe 40,000 years ago.

Prof Richard Klein believes art is a landmark in human evolution. Unquestionable art that's widespread and common suggests you're dealing with people just like us.

No other animals, after all, are able to define a painting as anything other than a collection of colours and shapes. This ability is unique to humans. Other scientists agree. They believe art defines humans as behaviourally modern, and its beginning must coincide with the ability to speak and use language.

If someone has the imagination to devise a shared way to describe their environment using art then it seems inconceivable that they could not possess language and speech.

Watch the full documentary now (playlist - 46 minutes)