"Pain is both a sensory and emotional experience, generally associated tissue damage, or inflammation. Pain is ultimately a perception, and not an objective bodily state."

The problem with the Turing Test is that it presents a conundrum of scientific method. We presume that improvement to machines takes place, so there is a starting state in our experiments where the human is considered "smarter", whatever that means, than the computer. We are measuring a change in human ability to discriminate between human and machine behaviour. But the human is defined as the most flexible element in the measurement loop at the start, so how do we know we aren't measuring a state change in the human, rather than in the computer? Is there an experimental difference, in this setup, between computers getting "smarter" and humans getting "stupider"? I don't think so.

http://www.medicalnewstoday.com/articles/207629.php
http://www.cell.com/abstract/S0092-8674(10)01133-5#Summary