Big, brutish and stupid - it's a commonly held view of our prehistoric predecessors; they were as wild as the animals they hunted.
By Helen Sewell
BBC News Online science staff
But it's not one the science tends to support.
Much can be gleaned from fossil evidence but much else remains guesswork
New discoveries are revealing just how sophisticated some of our ancestors were and how much further back in time that complexity of behaviour existed - much earlier than we thought.
This is the picture that emerges from the BBC's new television series Walking With Cavemen.
It takes the viewer back three-and-a-half million years to show how modern humans evolved.
The series follows the lives of individuals at each step in the evolutionary process, exploring their habits and behaviours and pointing out the traits we share today.
"What intrigued me the most is how much of the caveman remains in us today and how much we are shaped by these bizarre creatures that have come before us" said director Richard Dale.
"It makes you stop and think," added Peter Georgi, the series producer. "It makes you realise that practically everything you do comes from how these early creatures behaved, from the way they ate their food to the way they competed for attention."
Actors take the part of our ancestors
The study of early humans is one of the most hotly contested subjects in science today, and the programme makers consulted more than 100 scientists, from experts in weather and stone tool-making, to geneticists and primatologists.
Palaeontologists have dug up a number of skeletons, from the earliest hominid that walked on two legs, Australopithecus arafensis, to Homo heidelbergensis, the first to survive by imagination and ingenuity.
Bringing them back
The skulls of different species have different shapes and sizes. Some have jutting brow ridges, others have larger or smaller teeth.
What we know of their skeletal features gave the Walking With Cavemen team a good idea of early humans' anatomy and how they moved.
HUMAN FAMILY TREE
Scientists are trying to piece together the species relationships
Animatronics experts and prosthetics makers used the fossil evidence to construct likely replicas of their bodies and faces.
"What we've made is fascinating connections," said Richard Dale. "We have pooled together the best scientific evidence in the world to recreate our ancestors and make them look as realistic as possible, not in the Hollywood sense of the word, but as scientists know they looked."
Peter Georgi added: "It's the most modern, scientifically accurate rendition of our modern human ancestors ever done for television or film."
Filling in gaps
But much of it remains pure guesswork. The fossil evidence is fragmentary; some of the interpretation is very speculative. Researchers have their pet theories and the arguments among scientists can be very fierce.
This lack of definitive information about early human traits is something that frustrates Professor Clive Gamble, from the University of Southampton. He cites, as an example, the hair of Neanderthals.
"We don't know if it was long and straight or short and curly, and we'll never know" he told BBC News Online.
Homo heidelbergensis was an accomplished hunter
He suspects that Neanderthals, which are portrayed in the series as rather unkempt, were likely to have been quite keen on grooming. He thinks their appearance may have been much neater, perhaps with slicked back hair.
Some anthropologists believe their hair might even have been red.
Live or die
Some of the behaviour of our early predecessors, though, was easier to piece together than their facial features, with the skeletons yielding a large number of historical facts.
Different types, or isotopes, of carbon atoms taken from the bones indicate whether a species ate primarily plants, meats or fish.
Scientists have also managed to extract DNA from some bones, which can be compared with modern human DNA.
Meaning: "Robust" boisei after US industrialist Charles Boise who funded discoverer Mary Leakey
Time: This gentle vegetarian creature lived approximately 2.5-1m years ago
Fossil: Leakey found a skull at Olduvai Gorge, Tanzania, in 1959. Further find at Koobi Fora, Kenya
Meanwhile archaeological evidence of stone tools and wooden implements shows how each species lived and how they used their environment for getting food, whether hunting animals or gathering fruits.
The series sees the ancient primates moving from their origins in East Africa across to the Middle East, Asia and China, and finally into the hardships of the Ice Age in Northern Europe and into a devastating drought in Southern Africa.
The programmes show how they had to keep up with their changing environment or die.
Species like Homo heidelbergensis, fierce hunters with sophisticated tools who lived in close-knit family groups, managed to evolve. Many scientists think they eventually gave rise to Neanderthals and Homo sapiens, modern humans - us.
But those like the earlier species of Paranthropus boisei, whose behaviour was specialised for survival in only one niche, didn't manage to make it.
Walking With Cavemen is a four-part series that starts on BBC One on 27 March