Theoretically, it seems possible that sometime in the future there may be a computer that is capable of duplicating the memory feats and computing abilities of a human brain. However, some time will have to pass before that happens.This is because-with about 100billion nerve cells, each of which is connected to another 10,000 or so neutrons-the natural neutral networks inside our heads still make any computers look slow. In particular, the ability to process many stimuli and signals in parallel is still underdeveloped in computers. Currently the world's fastest supercomputer-Blue Gene/L at the Lawrence Livermore National Laboratory in the USA-performs 280.6 trillion calculations per second-in computing jargon, 280.6teraflops.It has been calculated that even a rough replication of the human brain would require a machine capable of at least 10,000 teraflops.
Turing and is still consider the most important hurdle for so-called intelligent machines to overcome.
Turing stipulated that a computer could be described as intelligent when a human judge, addressing an unknown source at the other end of an electronic link-a phone line or terminal-could not tell whether the source was human or machine.
During the annual contest for the Loebner Prize for Artificial Intelligence, which is based on the Turing test, the aim is for three out of 10judges to be fooled for at least five minutes by the answers provided by a computer. So far no machine has ever achieved this.