Though a number of studies have been conducted to explore the influence of the use of pre-recorded and live-link testimony within criminal trials upon (mock) juror perceptions and jury verdicts, there is considerable diversity in terms of the scale and methodological rigour of that existing research. The trial simulations relied upon have varied significantly in their level of detail and realism, as well as between written transcript, audio recording, video re-enactment or live performance formats. The size and composition of mock jury samples has also varied across these studies. These factors must be born in mind when evaluating study findings, both on their own terms and in terms of their transferability to the real criminal courtroom.
Nonetheless, such research does yield some significant and valuable insights into the factors that may frame evaluations of witnesses and their evidence during jury deliberations, in a context in which direct research with real jurors on the substance of their decision-making is still prohibited in many jurisdictions, including Scotland.
From the available research, there appears to be no compelling evidence of an impact per se from the use of pre-recorded evidence or live-links, whether by child or adult witnesses, that translates reliably into an effect on verdict outcomes in criminal trials.
In respect of child witnesses, it has often been found that jurors may harbour an initial preference for evidence delivered ‘live and in the flesh’. However, a number of studies have now also established that, where a group deliberation component is built into the research design (mimicking the real trial process), this influence is neutralised such that it does not translate in any consistent or reliable way into verdict outcomes.
In respect of adult witnesses, the evidence base is significantly more limited. However, robustly designed studies, both in Australia and England, indicate that the use of pre-recorded evidence or link-links, at least by female rape complainers, does not significantly effect juror evaluations. The position in respect of adults in other trial contexts is less clear, and requires further investigation. As things stand, however, there is good reason to think that, as with child witnesses, any juror preferences for live testimony may be mitigated in the process of deliberation.
That this may be so in the experimental context, however, does not entail that additional complications associated with the practical use of such testimony within real criminal courtrooms (including in respect of the audio visual quality and length of recorded evidence, for example) may not produce their own distinctive influences upon jurors, and this would need to be warded against in any plans for implementation.