"I began by studying artists," he explains, from his holiday home in Montana. "When I observed and photographed them, I noticed that once they began to be absorbed by their work they went into an almost trance-like state of complete involvement - they didn't hear when you spoke to them, they forgot to eat. It was a very important, special part of their lives. So, I tried to figure out if other people can get to the same level of absorption. Once I started looking, it became clear that children at play, chess players, mountain climbers, all had the same complete involvement in what they were doing." Reading, driving, composing music, athletics can all trigger flow - as can work - and achieving flow makes an activity intensely rewarding. But Czikszentmihalyi, who is publishing his findings in a new book out tomorrow, Living Well, was initially surprised to find that few people experience flow during their leisure time - supposed to be the most rewarding time of all.
"It's counter-intuitive," he says. "Most people would rather work less and have more leisure time. But at work, people tend to be more energetic and creative than at home. At home, there is no feedback, no sense of clear goals, so, in fact, people tend to feel less and less energetic. Free time is not all it's cracked up to be." The problem, he believes, is that people think doing nothing is an end in itself - when in fact, using leisure time for enjoyment requires application. He gives the example of reading ("active leisure", activity that leads to high levels of flow) versus watching television ("passive leisure", low flow). "Almost all active, leisure requires an initial input of energy to produce flow," he explains. "You need to read about 20 pages to enter the flow state, to immerse yourself in a virtual world. In front of the television, you are immediately exposed to the finished product and don't make that initial investment. The easy way may seem enjoyable and rewarding, but in fact if you put in some energy, you get more out in the long run."
He has carried out research in Europe and the US and concludes that while most people can achieve flow, an unfortunate 15 per cent or so of the population just can't concentrate sufficiently to make it. "The state has been known for a long time," he says. "It's referred to in cultures like that of China in 4BC, in Hindu yoga, and in many other cultures, including our own. I did not invent it, I am simply trying to describe the phenomenon in more contemporary ways of relating to human behaviour."
His book aims to help people for whom flow is elusive. "The big enemy of flow is passive acceptance of things. Life is infinitely malleable and flexible, and you can make something out of it, whoever you are. Some people never think about fulfilling themselves - they think it is somehow their lot to lead boring lives. If you believe there are better ways of living, you need to get on and discover what's missing in your life, whether it's music, drawing, or simply walking on the seashore."
'Living Well: The Psychology of Everyday Life' is published by Weidenfeld & Nicolson (pounds 11.99).