The power and persistence of contextual priming: more risks in using police transcripts to aid jurors' perception of poor quality covert recordings

A poor quality covert recording from an Australian murder case, along with the police transcript used in the trial but later shown to be inaccurate, are used to explore general issues regarding this increasingly common type of evidence. Two experiments were run, in which participants heard an excerpt from the audio, first with no transcript, then with suggested and alternative transcripts. In Experiment 1, they were given no contextual information, while Experiment 2 started with a background story about the case and the issue the recording was intended to resolve. Results indicate that background knowledge of a case can dramatically increase listeners' acceptance of a police transcript, even when the transcript is manifestly inaccurate. It is suggested that such contextual priming may affect not just juries but others involved with the trial, and recommended that police transcripts be treated with more caution than is currently common with Australia's 'ad hoc expert' rules.