A Reverse Turing test is a Turing test in which the objective or roles between computers and humans have been reversed. Conventionally, the Turing test is conceived as having a human judge and a computer subject which attempts to appear human. The intent of this conventional test is for the judge to attempt to distinguish which of these two situations is actually occurring. It is presumed that a human subject will always be judged human, and a computer is then said to "pass the Turing test" if it is also judged human. Critical to the concept is the parallel situation of a human judge and a human subject, who also attempts to appear human. Any of these roles may be changed to form a "reverse Turing test". Reversal of objective Arguably the standard form of the reverse Turing test is one in which the subjects attempt to appear to be a computer rather than a human. A formal reverse Turing test follows the same format as a Turing test. Human subjects attempt to imitate the conversational style of a conversation program. Doing this well involves deliberately ignoring, to some degree, the meaning of the conversation that is immediately apparent to a human, and the simulation of the kinds of errors that conversational programs typically make. Arguably unlike the conventional Turing test, this is most interesting when the judges are very familiar with the art of conversation programs, meaning that in the regular Turing test they can very rapidly tell the difference between a computer program and a human acting normally. The humans that perform best in the reverse Turing test are those that know computers best, and so know the types of errors that computers can be expected to make in conversation. There is much shared ground between the skill of the reverse Turing test and the skill of mentally simulating a program's operation in the course of computer programming and especially debugging. As a result, programmers (especially hackers) will sometimes indulge in an informal reverse Turing test for recreation. An informal reverse Turing test involves an attempt to simulate a computer without the formal structure of the Turing test. The judges of the test are typically not aware in advance that a reverse Turing test is occurring, and the test subject attempts to elicit from the 'judges' (who, correctly, think they are speaking to a human) a response along