The Big Question: Why are games consoles the focus of the battle between computer giants?

Why are we asking this now?

Because the three major computer console manufacturers – Nintendo, Sony and Microsoft – are currently engaged in a titanic struggle to dominate our lives and make sure that we never leave our living rooms. This week the good and the great of the computer games industry are meeting in Los Angeles for the annual E3 convention, the most important and glitzy event in the industry's calendar. A whole new plethora of gadgets and gizmos have been unveiled which reveal just how much the console manufacturers are looking to expand their horizons to attract new customers outside the traditional teenage male demographic.

What is the hottest trend of the convention so far?

Two words: motion controllers. Ever since Nintendo stormed on to the scene two and a half years ago with their boundary-breaking Wii controllers, Sony and Microsoft have been playing a desperate game of catch-up. But over the past 48 hours both companies have now unveiled their own motion sensor prototypes which will likely be available in the shops sometime next year.

Why is there so much fuss about motion controllers?

Because they have completely transformed the way we play video games and have helped attract a whole new audience of gamers who, until recently, might have thought consoles were just for pimply teenagers. Using clever technology and motion sensors, computer consoles can now detect the position, distance, movement and speed of a controller's hand. Nintendo were the first to capitalise on the technology and developed a whole range of games to go with it. Suddenly the computer controller was more than just a box with buttons. It could be virtually anything – a tennis racket, a sword, a steering wheel, a gun. You name it.

So what have Sony and Microsoft showcased?

Microsoft was the first to steal the headlines with a motion sensor prototype called Project Natal. It wheeled out Hollywood director Stephen Spielberg to introduce the product which he described as "a window into what the future holds". Project Natal is so unusual because it completely forgoes the need for a controller. Motion sensors and facial recognition software will allow their console, the Xbox 360, to follow the movement of a human body as well as tell what mood the player is in. Sony, meanwhile, has opted for a less radical but probably easier-to-develop motion controller which works in a similar way to the Nintendo Wiimote. The major difference however is that the PlayStation 3, Sony's console, will be able to track the controller's movements in 3D by judging how close it is to the screen. Nintendo's Wii controllers only use D technology.

So who is winning the console war?

If you go by sales figures then Nintendo has completely dominated the market. Since they released their Nintendo Wii in November 2006 the Japanese company have sold an astonishing 50m units worldwide. The Xbox 360 was released a year earlier and has shifted 30m units. The PlayStation 3, which went head to head with the Wii, has so far sold a mere 22m units worldwide.

Why is the Wii so popular?

Price may have had something to do with it – the Wii was much cheaper than its rivals when it launched. But what really helped Nintendo was that the Wii persuaded a whole new demographic to play computer games. "What Nintendo did was very clever," says Michael Brook, editor of T3 magazine. "Sony and Microsoft were desperate to outdo each other with their new consoles, particularly when it came to power and graphics, the kind of things that appeal to the usual teenage gamer. So Nintendo went back to the drawing board and developed a console that would appeal to everyone, especially families. The graphics aren't as strong but the game play is incredibly innovative and inclusive." Software developers also brought out a whole range of family-friendly games while applications like Wii Fit – which mixes fitness exercises with a video game – have been a runaway success.

So games are as important as consoles?

Absolutely. Without good games, consoles are little more than boxes of electronic gadgetry. Since it was released a little over a year ago Wii Fit alone has sold 18m units, making it one of the biggest-selling video games of all time. In fact, the video game market has become so huge that it has begun outstripping music and movie sales.

Earlier this year, Capcom released Resident Evil 5, part of a long-running and highly popular series of games where players have to escape from hordes of deadly zombies. By the end of the first week Resident Evil 5 had not only topped the gaming charts, it had also outsold all the music singles and albums sold that week as well as grossing more than any movie at the box office.

And now celebrities are joining in the frenzy?

Where there's money to be made, you can guarantee celebrity endorsements will not be far behind. Earlier this week, in another publicity coup for Microsoft, Sir Paul McCartney and Ringo Starr appeared on stage together for the first time in years to launch a Beatles version of the popular game Rock Band. Like Guitar Hero (its main rival), the idea of Rock Band is to press buttons in time to music tracks, often on instrument-shaped controllers. The Beatles' version of Rock Band is the first time that any Beatles music has been licensed to a third party. Not to be outdone by their rivals, Guitar Hero this week used rappers Jay-Z and Eminem to launch their new game DJ Hero.

Are computer consoles good for children?

It depends which psychological studies you read but academic opinion is generally divided. It's certainly true that thanks to computer consoles today's children are spending more time vegetating in the living room than ever before. There are also concerns that the violent content of some video games may encourage violence within children although once again there is very little consensus among child psychiatrists.

On the plus side there have been some studies that show computer games actually help a child develop better hand-to-eye coordination skills and quicker reaction times. The image of computer game playing being a solitary affair is also changing thanks to the fact that online gaming, where players compete against and talk with fellow players all over the world through the internet, promotes socialising (albeit in a virtual form).

So what does the future hold?

Both Microsoft and Sony have made no secret of the fact that they'd like our living rooms to be dominated by a mutli-faceted games consoles that provide us with all our entertainment needs. Both the Xbox and PlayStation already have hard drives that allow users to store large amounts of music and video which can then be played through the console, making them, in effect, entertainment suites rather than just games consoles.

In the not too distant future we'll be able to use our consoles to surf the internet, download games, play virtual tennis, paint pictures and video-phone relatives overseas all at the click of a button or swish of a controller. We'll never need to leave our sofas again.

Will Sony and Microsoft ever catch up with Nintendo?

Yes...

* Their new controllers show how both companies are willing to adapt.

* Once motion controllers are on all platforms there will be no reason to just stick to Nintendo.

* The computer power or the PlayStation and Xbox 360 make them much more technologically durable than the Wii.

No...

* The Wii appeals to a much wider demographic than Sony or Microsoft ever will.

* Nintendo have made the Wii so much more affordable than its rivals that its pre-eminence is assured.

* Most people who wanted a PlayStation or Xbox have already bought them.