Eyewitness researchers know that the police lineup is, at center, a psychological experiment designed to test the ability of a witness to recall the identity of the perpetrator of a crime. As such, it is recommended that police lineups be conducted in double-blind fashion, like any scientific experiment, in order to avert the possibility that inadvertent cues from the lineup administrator will suggest the "correct" answer and thereby subvert the independent memory of the witness. The occurrence of "experimenter bias" is well documented across the sciences. Researchers recommend that police lineups be conducted by someone who is not connected to the case and is unaware of the identity of the suspect.