Mock Juror's Perceptions of a Child Witness Passing or Failing a Truth and Lies Discussion or Promising to Tell the Truth

This study examined the effect of a child passing or failing the UK truth and lies discussion (TLD) compared with the Canadian promise to tell the truth on mock jurors' decisions regarding witness credibility and truthfulness and defendant guilt. Ninety-two participants read a vignette that described a child witnessing his father physically attacking his mother. The vignette was manipulated for witness age (age 4 years and age 8 years) and TLD performance/promise. Supporting the hypotheses, participants rated the witness's credibility and truthfulness significantly higher after a witness passed a TLD and after promising to tell the truth. The age of the child witness did not significantly affect jurors' decision making. The results are discussed in relation to arguments regarding the abolition of the UK's TLD in favour of introducing a promise to tell the truth.