Singer testified as a brainwashing expert at the trial of Patty Hearst, presenting her conclusions that Hearst had been brainwashed, but outside the jury's presence. Singer described Hearst as "a low-IQ, low-affect zombie" and testified that by using speech patterns, she determined that Hearst was reading statements prepared by her captors. Prosecutors argued that Singer's testimony should not be presented to the jury because brainwashing had never before been accepted as a field of expertise upon which expert testimony could be presented. The judge decided in favor of the prosecution, and Hearst was convicted. Singer's testimony was widely reported, which increased her reputation as a brainwashing expert.