One of the finer points in the law on evidence is whether a defendant in a criminal case can present hypnotically refreshed testimony as part of his defense.
What is hypnotically refreshed testimony? In layman’s terms, it is testimony on details of an incident that a party or witness is able to recall after undergoing hypnosis under the supervision of an expert.
In the United Sates, the US Supreme Court has categorically ruled on the issue. In Rock vs. Arkansas, 483 U.S. 44 (1987), the petitioner was accused of shooting her husband with a handgun. However, she could not remember whether she actually pulled the trigger or the gun accidentally fired off. She underwent hypnosis and was able to recall that she had her thumb on the hammer of the gun and no finger on the trigger. She also recalled that the gun had discharged when her husband grabbed her arm during the scuffle. Her counsel arranged for a gun expert to examine the handgun. The inspection revealed that the gun was defective and prone to fire, when hit or dropped, without the trigger being pulled.
Due to a rule evidence in Arkansas, the hypnotically refreshed testimony was not admitted. It was then brought to the US Federal Supreme Court where it overruled the Arkansas Supreme Court. It held that a criminal defendant has a constitutional right to testify in his own defense. Despite any unreliability that hypnosis may introduce into the testimony, the procedure has been credited as instrumental in obtaining particular types of information and the hypnotically refreshed testimony was verified by corroborating evidence and traditional means of assessing accuracy and inaccuracies and safeguards.