A In 1969, a fossil hunter named Rod Wells came to Naracoorte in South Australia to explore what was then known as Victoria Cave. Wells clawed through narrow passages and eventually entered a huge chamber. Its floor of red soil was littered with strange objects. It took him a moment to realise that he was looking at the bones of thousands of creatures that had fallen through holes in the ground above and become trapped. Some of the oldest belonged to mammals far larger than any found in Australia today: the ancient Australian megafauna, huge animals of the Pleistocene epoch. Across the continent, scientists have found fossils of a giant snake, a huge flightless bird and a seven-foot kangaroo. Given how much attention has been devoted to the extinction of the dinosaurs, it is surprising that more has not been written about megafauna. Prehistoric humans never hunted Tyrannosaurus rex, but they really did hunt mammoths and mastodons.

B The disappearance of American megafauna happened relatively soon after human beings arrived, about 13,000 years ago. In the 1960s, paleoecologist Paul Martin developed what became known as the blitzkrieg hypothesis. He argued that modern humans created havoc as they spread through the Americas, killing animals that had never faced a technological predator. Yet the extinction was not comprehensive. North America retained deer, black bears and a small type of bison, while South America retained jaguars and llamas.

C For years, scientists blamed the extinction of Australia’s large animals on climate change. Australia had been drying out for a million years or more, and the megafauna faced a continent where vegetation was disappearing. Australian paleontologist Tim Flannery suggested that humans, who arrived around 50,000 years ago, used fire to hunt, leading to deforestation and the loss of habitat. In 1994 he published The Future Eaters, proposing an Australian version of the blitzkrieg hypothesis. The book was controversial, and some regarded it as critical of the Aborigines. More importantly, there is no direct evidence that humans killed the megafauna: no animal has been found with a spear point embedded in a bone, and no clear kill site has been discovered.

D The debate depends heavily on techniques for dating old bones and the sediments in which they are buried. If scientists could show that the animals disappeared shortly after humans arrived, the case for human responsibility would be stronger. At Cuddie Springs in New South Wales, archaeologist Judith Field found megafauna bones beside stone tools in 1991. She identified two layers, around 30,000 and 35,000 years old, which would suggest that humans and megafauna lived together for about 20,000 years. Critics argue that the fossils were moved from their original positions and redeposited in younger sediments, so the order of events is uncertain.

E Another famous boneyard is Wellington Caves, where Diprotodon, the largest known marsupial, was first discovered. In 1830, a local official named George Rankin lowered himself into a cave on a rope tied to a protrusion in the wall; the protrusion turned out to be a bone. A surveyor, Thomas Mitchell, later explored the caves and sent fossils to the British paleontologist Richard Owen, who recognised that they belonged to an extinct marsupial. Between 1909 and 1915, sediments containing fossils were hauled from Mammoth Cave and examined in a haphazard manner that no scientist today would approve. One bone has attracted particular attention: a femur with a cut in it, possibly made by a sharp tool.

F Unfortunately, the Earth preserves its history haphazardly. Bones disintegrate, the land erodes, the climate changes, forests come and go, and rivers change their course; the past is steadily concealed. Narratives must therefore be constructed from limited data. Australia’s first people expressed themselves in rock art. Paleontologist Peter Murray has studied a painting in far northern Australia that resembles a megafauna marsupial called Palorchestes. Another site in Western Australia appears to show a hunter with either a marsupial lion or a Tasmanian tiger. The distinction matters because the marsupial lion became extinct, whereas the smaller Tasmanian tiger survived into recent historical times. As Murray says, every step requires interpretation: the data does not speak for itself.

For a fascinating tale about creativity, look at a cleaning product called the Swiffer and how it came about, urges writer Jonah Lehrer. In the story of the Swiffer, he argues, we have the key elements in producing breakthrough ideas: frustration, moments of insight and sheer hard work. The story starts with a multinational company which had invented products for keeping homes spotless, and couldn’t come up with better ways to clean floors, so it hired designers to watch how people cleaned. Frustrated after hundreds of hours of observation, they one day noticed a woman do with a paper towel what people do all the time: wipe something up and throw it away. An idea popped into lead designer Harry West’s head: the solution to their problem was a floor mop with a disposable cleaning surface. Mountains of prototypes and years of teamwork later, they unveiled the Swiffer, which quickly became a commercial success.

Lehrer, the author of Imagine, a new book that seeks to explain how creativity works, says this study of the imagination started from a desire to understand what happens in the brain at the moment of sudden insight. ‘But the book definitely spiraled out of control,’ Lehrer says. ‘When you talk to creative people, they’ll tell you about the “eureka”* moment, but when you press them they also talk about the hard work that comes afterwards, so I realised I needed to write about that, too. And then I realised I couldn’t just look at creativity from the perspective of the brain, because it’s also about the culture and context, about the group and the team and the way we collaborate.’

When it comes to the mysterious process by which inspiration comes into your head as if from nowhere, Lehrer says modern neuroscience has produced a ‘first draft’ explanation of what is happening in the brain. He writes of how burnt-out American singer Bob Dylan decided to walk away from his musical career in 1965 and escape to a cabin in the woods, only to be overcome by a desire to write. Apparently ‘Like a Rolling Stone’ suddenly flowed from his pen. ‘It’s like a ghost is writing a song,’ Dylan has reportedly said. ‘It gives you the song and it goes away.’ But it’s no ghost, according to Lehrer.

Instead, the right hemisphere of the brain is assembling connections between past influences and making something entirely new. Neuroscientists have roughly charted this process by mapping the brains of people doing word puzzles solved by making sense of remotely connecting information. For instance, subjects are given three words – such as ‘age’, ‘mile’ and ‘sand’ – and asked to come up with a single word that can precede or follow each of them to form a compound word. (It happens to be ‘stone’.) Using brain-imaging equipment, researchers discovered that when people get the answer in an apparent flash of insight, a small fold of tissue called the anterior superior temporal gyrus suddenly lights up just beforehand. This stays silent when the word puzzle is solved through careful analysis. Lehrer says that this area of the brain lights up only after we’ve hit the wall on a problem. Then the brain starts hunting through the ‘filing cabinets of the right hemisphere’ to make the connections that produce the right answer.

Studies have demonstrated it’s possible to predict a moment of insight up to eight seconds before it arrives. The predictive signal is a steady rhythm of alpha waves emanating from the brain’s right hemisphere, which are closely associated with relaxing activities. ‘When our minds are at ease – when those alpha waves are rippling through the brain – we’re more likely to direct the spotlight of attention towards that stream of remote associations emanating from the right hemisphere,’ Lehrer writes. ‘In contrast, when we are diligently focused, our attention tends to be towards the details of the problems we are trying to solve.’ In other words, then we are less likely to make those vital associations. So, heading out for a walk or lying down are important phases of the creative process, and smart companies know this. Some now have a policy of encouraging staff to take time out during the day and spend time on things that at first glance are unproductive (like playing a PC game), but day-dreaming has been shown to be positively correlated with problem-solving. However, to be more imaginative, says Lehrer, it’s also crucial to collaborate with people from a wide range of backgrounds because if colleagues are too socially intimate, creativity is stifled.

Creativity, it seems, thrives on serendipity. American entrepreneur Steve Jobs believed so. Lehrer describes how at Pixar Animation, Jobs designed the entire workplace to maximise the chance of strangers bumping into each other, striking up conversations and learning from one another. He also points to a study of 766 business graduates who had gone on to own their own companies. Those with the greatest diversity of acquaintances enjoyed far more success. Lehrer says he has taken all this on board, and despite his inherent shyness, when he’s sitting next to strangers on a plane or at a conference, forces himself to initiate conversations. As for predictions that the rise of the Internet would make the need for shared working space obsolete, Lehrer says research shows the opposite has occurred; when people meet face-to-face, the level of creativity increases. This is why the kind of place we live in is so important to innovation. According to theoretical physicist Geoffrey West, when corporate institutions get bigger, they often become less receptive to change. Cities, however, allow our ingenuity to grow by pulling huge numbers of different people together, who then exchange ideas. Working from the comfort of our homes may be convenient, therefore, but it seems we need the company of others to achieve our finest ‘eureka’ moments.