Way back in 1970, Japanese roboticist Masahiro Mori hypothesized that people will find artificial humans increasingly repulsive as they inch closer to perfection.

Known as the uncanny valley, Mori suggested that while emotional responses to an android will be increasingly positive as they become more human-like in appearance and motion, there is a point where the artificial creations become "more human" but not "human enough" and our response actually turns negative.

The intricacies and complexities of the human face and body are certainly known intimately and instinctively by us all. We are not easily fooled and even the slightest imperfections are unsettling.

The uncanny valley is a concept that gamers are becoming increasingly familiar with as the ever-growing processing power of PCs and consoles allows more realistic modeling of human characters.

Unfortunately, what routinely grace our screens at the moment are characters with eerily vacant stares, rigid movement, appalling lip-syncing and plastic skin. Most "realistic" game characters actually look more like cadavers.

Rather than the attempted photorealism of Square's famous misstep Final Fantasy: The Spirits Within or 2004's The Polar Express (which polarized viewers between repulsion and fascination), the most convincing virtual characters are usually stylised creations, such as Ico's beautiful Yorda, The Sands of Time's nimble Prince of Persia or Tomb Raider's buxom Lara Croft.

The artists at Pixar certainly take care to stylize their rare human characters, avoiding tumbling into the valley.

It will be fascinating to see how long it takes game developers to bridge the gap between the unnervingly artificial and the convincingly real, if indeed it is ever possible.

One of next year's biggest games for PlayStation 3, Heavy Rain, could be the next big step forward. But Gamesmaster is certainly not as confident as Neverwinter Nights creators Obsidian, who recently predicted the games industry will be able to cross the valley in "another year or two".

What game characters have you found most convincing and most grotesque?