当你遇到困难的时候，会怎么办？找专家？问朋友？或者你会找陌生人来帮你解决问题，你付钱给他们作为回报？这正是“挑战奖”背后的初衷。近来，“挑战奖”这个概念再次受到人们的欢迎。

What do you do when you have a problem? Do you go to an expert, ask your friends to come up with an idea? Or, given the chance, would you ask a crowd of strangers for a solution? It may sound strange, but it has spurred more than a few successful innovations. That's the thinking behind a 'challenge prize'.

Challenge prizes come in many shapes and sizes but the basic concept remains the same. Rather than consulting and paying an expert to innovate a solution, you offer the prize up to anyone who believes they can solve it and present the first to do so with a prize. This might sound odd - many would argue, 'Who is better qualified than an expert?' But actually, not using one seems to result in a great deal of thinking outside of the box.

Some argue that formal education can kill creativity because it sometimes only teaches a single solution to a problem or single method to achieve a task. In the same way, some suggest that experts can suffer from tunnel vision. "If we launch an XPRIZE and it's just the 'experts' that come out and compete, they're usually the ones that will tell us it can't be done." says Marcus Shingles, former CEO of the XPRIZE Foundation, which organises challenge prizes today.

There are other advantages too. "You're not asking people to use a particular solution set on how to solve that problem. So you get this tremendous amount of diversity." adds Shingles. And because the crowd acts like an impromptu think tank, its lateral thinking can throw up issues that may have been overlooked.

Challenge prizes were most popular during the 18th and 19th centuries, but have received renewed interest more recently. Historically, many practical inventions have been conceived in this way – for example, the tin can. More recently, Virgin Galactic, a company hoping to commercialise space flight, developed out of the Ansari XPRIZE 2004 winner Tier One. They successfully launched a reusable spacecraft that left the Earth's atmosphere twice in two weeks. The prize was $10m.

However, there are dangers connected to blue-sky thinking. "You don't want to be creating a challenge prize which incentivises people to solve a problem where there is no demand," says Tris Dyson, executive director of challenge prizes at Nesta, a UK-based innovation foundation. This happened in 1979 where a Kremer prize of £100,000 was claimed by the first person to fly under human power across the English Channel. Despite its successful completion, it has not led to the adoption of human-powered flight as a form of travel. And of course, there are those who invest their personal time and money only to see no return at all: someone else claims the prize, or they find that the reward does not match the resources they invested.

The pros and cons of challenge prizes affect both problem-setters and problem-solvers. But they don't seem to be going out of style anytime soon. To many, the challenge to innovate, the lure of the prize and the prestige of being first is too much to resist. And there's no solution for that.