Is it best for a judge to give intructions to a jury before or after a trial and are written or spoken instructions best?
In practice, judges often give instructions at the start of trials as well as at the end (when instructions are always given), though the purpose of the instructions might differ (see below). Certainly instructions given at the end stay in the memory for longer, and should make more sense, given that jorors have now had the opportunity to hear the evidence and the arguments. In the UK, instructions are invariably verbal, though they may be accompanied by written instructions at the jury's request (often during their deliberations where clarification of law is needed) or at the judge's discretion.
In considering instructions to the jury, it is natural to think first of the instructions at the end of the trial. But although these instructions are of crucial importance, there are often other occasions during the trial when the jury is instructed by the judge. Some judges choose to give a brief instruction on the law controlling the case at the beginning of the trial. Even during the trial, a judge may stop the taking of testimony to instruct the jury about the law surrounding an item of evidence.
However, it is at the end of trial that the judge gives the complete body of instructions to the jury. The instructions, of course, go into careful detail on the meaning of each of the elements of the crime, but they also cover many other general matters. A jury is usually instructed on such varied matters as the prosecution's burden of proof and the presumption of innocence, the meaning of reasonable doubt, the use of circumstantial evidence, the credibility of witnesses, the jury's role as fact finder, any defences that have been raised, and the procedures to be followed in the jury room.
Before the judge instructs the jury, the prosecution and the defense will normally also have an opportunity to submit instructions they wish the judge to give the jury. There may be an adjournment where there is a discussion (in the USA, 'conference') between the judge and the barristers outside the hearing of the jury at which the judge hears argument from the lawyers about the instructions to be given.
If, during its deliberations, the jury feels that it needs more guidance, it so informs the judge, and the judge may repeat or further clarify any of the earlier instructions. In addition, if the jury is having difficulty in reaching a verdict, the judge often gives a supplementary instruction asking members of the jury to listen carefully to the arguments of other jurors and encouraging them not to hesitate to reexamine their own views.
Normally the verdict of the jury in criminal cases must be unanimous. Not all juries are able to reach such a verdict. When a jury indicates that it is deadlocked, the judge usually asks it to continue deliberations until the judge is convinced that further deliberations would be futile. If no verdict can be reached despite continued deliberations, the judge may state that he is prepared to accept a majority verdict, or else will discharge the jury. In the UK, this would then normally result in a re-trial with a new jury; in the US this is seldom the case, because of the principle of 'double jeopardy'.
In theory, jurors are expected to apply the law to the facts of the case. However, a verdict rarely reveals whether the jury has applied the judge's legal instructions, or whether the jury has applied the judge's instructions accurately. Thus, trial and appeal courts are left to assume that the jury has followed the judge's instructions when the verdict is consistent with the law under at least one possible interpretation of the facts. Questions about the jury's use of the legal instructions typically arise at the appellate level only in the context of concerns about whether the trial judge has stated the legal standard accurately.
Jurors might fail to follow the judge's instructions on the law if they were either unmotivated or unable to apply the instructions. Jurors generally see themselves as obligad to apply the law, and often spend a significant portion of their time during deliberations discussing the law. Yet, there is also evidence that legal instructions as they are typically given often fail to provide jurors with helpful legal guidance. Studies of juror comprehension of several frequently used jury instructions have shown not only that comprehension was low, but also that it could be significantly improved if the instructions were reworded.
The traditional approach to jury instructions is to tell the jury only what it is supposed to do, and to avoid directing attention to any matter that the jury should ignore. But failing to address the erroneous beliefs that jurors might have does not make those beliefs go away, and it does not neutralise them. Jurors come to court with expectations and beliefs that can powerfully affect perceptions, attention, and recall. When instructions fail to correct inaccurate legal impressions, they miss the opportunity to provide jurors with a meaningful legal framework.
Although the most common source of deviations from legal standards is a failure of the legal instructions to convey clearly what the appropriate legal standard is, jurors also may deviate from the path outlined in the instructions due to bias and motivational obstacles. Jurors instructed to disregard particular information may find it difficult to do so. Other legal instructions may ask the jurors to engage in mental gymnastics that are not easy to perform, for example, to use a defendant's criminal record only to assist in evaluating his credibility, but not as evidence of bad character, or to forget that they learned about damaging evidence that the judge ruled inadmissible. Yet, jurors may be unwilling or unable to perform the required cognitive adjustments.
Finally, jurors may depart from the judge's legal instructions when the application of the legal standard to the particular case so substantially violates the jurors' sense of justice that they are persuaded to temper the letter of the law. This conduct has come to be known as 'jury nullification'. There is also evidence to indicate that when jurors are explicitly instructed that they have the right not to apply the law as the judge describes it, they are more willing to reach verdicts that temper the literal application of the law.
A complex issue! I hope this is helpful.