THE IMITATION GAME. “I believe that in about fifty years time it will be possible to programme computers with a storage capacity of about 10(9) to make them play the imitation game so well that an average interrogator will not have more than 70 per cent chance of making the right identification after five minutes of questioning.” (A.M. Turing, 1950).
http://www.abelard.org/turpap/turpap.php