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The Turing test might still be too hard for software to crack 鈥� but two programs have already aced video gaming鈥檚 answer to this famous evaluation of machine intelligence.

The two winning programs, or bots, relied on strategies of direct human mimicry to win an annual software tournament called 鈥� and beat an intriguing rival based on a stripped-down model of human consciousness.

As in the original Turing test, BotPrize bots attempt to convince human judges that they too are human. But whereas Turing test bots are judged on their ability to converse, in BotPrize, it鈥檚 the ability to play and navigate the 3D shoot-鈥檈m-up video game Unreal Tournament in a human-like manner that counts.

Multiple bots and human judges play simultaneously, all-against-all, and anonymously, in the same arena of battle. The idea is to design more realistic virtual characters, which, in turn, should make video games more compelling and software simulations used for training more useful. In the future, the software could drive physical robots capable of navigating the real world in a human-like manner.

In only the fifth ever BotPrize contest, the devised by Risto Miikkulainen and colleagues at the University of Texas, Austin, and Mirrorbot, the brainchild of Mihai Polceanu, currently studying at the European Centre for Virtual Reality in Brest, France, each . That鈥檚 more 鈥渉uman鈥� votes than the average human received 鈥� and almost twice as many as any bot has ever scored before. That means the 鈥渉uman-like barrier鈥� has been : the two teams shared the AU$7000 (拢4500) prize 鈥� which has never been awarded before 鈥� for bots considered to be on a par with humans.

How did the winning bots do it? As its name suggests, Mirrorbot鈥檚 key strategy is mimicry. When the bot meets other players in the game, it observes their behaviour. If it judges a fellow player to pose no immediate threat, it engages in a brief 鈥渟ocial interaction鈥�, in which it simply copies the actions of that player, including movement, shooting, weapon choice, jumping and crouching. 鈥淚t plays back what it sees,鈥� says Polceanu. The fact that this strategy proved successful at fooling the human says something interesting about AI and about ourselves, says Polceanu. 鈥淭his result may indicate that our perception of intelligence is not flawless, but significantly influenced by our social nature鈥�.

Mimicry is also one of the features of the other winner, UT^2, though not in real time, and only for one of its behaviours. During training, Miikkulainen鈥檚 team found that the bot鈥檚 most 鈥渦n-human鈥� behaviour arose when it became confused by obstacles such as walls. For example, a human knows intuitively how to navigate out of a doorway. A bot, by contrast, relies on its programming to work out that it must turn 90 degrees.

鈥淭here are bots that bounce back and forth and don鈥檛 realise the way out,鈥� says Miikkulainen. 鈥淚t鈥檚 amusing and interesting how challenging a very basic phenomenon can be.鈥�

His team recorded dozens of humans playing Unreal Tournament, spliced out the bits where the human released themselves from different geometries and then programmed the bot to deploy the human strategy used in a situation most similar to whatever it finds itself in. For other aspects of play, UT^2 deployed evolutionary learning, in which successful strategies were bred to produce offspring strategies that were even more human-like.

, meanwhile, a bot that came a close second in last year鈥檚 BotPrize 鈥� and interested New 杏吧原创 in the run-up to the contest because it was based on a leading model of human consciousness 鈥� lagged in fourth place out of a total of six bots.

Its creator, Zafeirios Fountas, of Imperial College London, blames this on technical constraints which forced him to 鈥減rune鈥� 20 per cent of his bots鈥� simulated 鈥渘eurons鈥�. 鈥淎s the results indicate, unfortunately, the removed neurons and synapses played a more crucial role than I believed,鈥� he says. 鈥淭he good news is that now I know that and I can investigate what exactly caused this change.鈥�

Where does all this leave AI? BotPrize is certainly considered a lesser challenge than the original Turing test. 鈥淚 am not making any claim that because the bots can appear human that they are intelligent,鈥� says of Edith Cowan University in Perth Australia, who created BotPrize in 2008.

Still, Miikkulainen says that intelligence is made of up of components, at least one of which has now been solved. 鈥淚n terms of spatial reasoning, it is possible to act human,鈥� he says. 鈥淟anguage is a much bigger problem, but it鈥檚 nice to know that in this part of intelligence, we can do well.鈥�

When this article was first posted, Mihai Polceanu鈥檚 surname was misspelled