ABSTRACT
DNA profding and other kinds of scientific evidence are playing an increasingly important role in criminal investigations and court proceedings. When a trial involves DNA evidence, jurors are generally presented with testimony about the way in which the crime scene DNA evidence was collected and how the crime lab processed the evidence and tested for any matches between the various crime scene and comparison samples. A major approach studying lay reactions to probabilistic DNA evidence used Bayes’s theorem to estimate the degree to which jurors should revise their belief that the defendant committed the crime given some incriminating trace evidence such as blood, semen or hair fibre. Jurors’ background and experiences can affect their opinion as to whether they consider an inclusionary DNA match report to be incriminating evidence. Jurors may also have expectancies about the trustworthiness of police officers who conduct criminal investigations and criminalists who collect DNA samples from the crime scene.
