ABSTRACT I INTRODUCTION II CORBETT AND THE PRESUMPTION OF JURY COMPETENCE III THE PRESUMPTION OF JURY COMPETENCE IN OTHER AREAS OF EVIDENCE LAW IV THE PRESUMPTION OF JURY COMPETENCE AND THE CURATIVE PROVISO V SARRAZIN: A BLOW TO THE PRESUMPTION OF JURY COMPETENCE? VI THE IMPACT OF SARRAZIN A Foothold for Questioning Cognitive Biases A Shift in the Burden of Proof VII CONCLUSION I INTRODUCTION
We should maintain our strong faith in juries which have, in the words of Sir William Holdsworth, "for some hundreds of years been constantly bringing the rules of law to the touchstone of contemporary common sense". (1) When instructions from a trial judge are flawed, the risk of prejudice to an accused is clear and a verdict can be overturned on appeal if necessary. However, when the legal instructions are proper but jury deliberations remain opaque and undisclosed, courts have questioned how well juries can comprehend the law and how accurately juries can apply the law to the facts at hand. The Supreme Court of Canada's opinion on the adherence of juries to their legal instructions has dramatically shifted over the past twenty years since R v Corbett, (2) from affirming trust in juries' capabilities to expressing doubts about the impact of subconscious influences on their decisions. The balance appears to be shifting in the direction of concerns about the frailties of the human reasoning process rather than the impact that questioning jury competence may have on public confidence in the Canadian justice system.
I will first examine the common-law basis for the presumption in Canada that juries act properly according to their instructions. I will then trace the effect and evolution of this presumption through other areas of evidence law and in the application of section 686(1)(b)(iii) of the Criminal Code, (3) commonly referred to as the curative proviso. Finally, I will examine the Supreme Court of Canada's recent decision in R v Sarrazin, (4) where the majority and dissent differed on the existence of the presumption of jury competence, and more importantly, on fundamental questions about the nature and capabilities of Canadian juries. The decision in Sarrazin is most known for reaffirming the current test for the curative proviso, but it also struck a significant blow at the presumption of jury competence. The majority accepted, based on "human experience", that the range of verdicts open to jurors may affect their decision. (5)
The reasoning in Sarrazin may impact the application of the curative proviso in two ways. First, the presumption that juries will act according to their instructions may have shifted from a presumption in favour of the Crown to an issue that must be argued evenly by both parties. Second, defence counsel may be able to successfully argue--without providing an evidentiary foundation other than common human experience--that a risk of prejudice exists where there is a risk that cognitive bias led the jury astray.
II CORBETT AND THE PRESUMPTION OF JURY COMPETENCE
The clearest foundation for a presumption that juries act according to their instructions emerged in Corbett, where the Supreme Court of Canada considered whether to permit cross-examination of an accused on his or her prior criminal record. While such cross-examination might be necessary to present a clear picture of the accused's credibility, there is a danger that bringing up past convictions might prejudice the jury against the accused. Chief Justice Dickson, for the majority, upheld section 12 of the Canada Evidence Act, which permitted such cross-examination. He reasoned that any risk that a jury might use evidence of prior convictions for an impermissible purpose could be corrected by providing "a clear direction as to the limited use they are to make of such information". (6)
The majority expressed significant concern about the troubling impact of putting "blinders" over the eyes of jurors as they carry out the truth-seeking function of the court. (7) Noting that counsel for the accused aggressively cross-examined Crown witnesses on their own past criminal records, the majority questioned whether, without similar information about the accused, the jury might be left with the misleading picture "that while all the Crown witnesses were hardened criminals, the accused had an unblemished past". (8) The majority determined that "the best way to balance and alleviate these risks is to give the jury all the information", (9) and to provide a limiting instruction clarifying that evidence of an accused's criminal record could only be used for the purpose of assessing his credibility. (10)
The majority's decision was grounded in the opinion that such instructions are effective at guiding the decision-making process of the jury. The decision was therefore based on the presumption that a jury will act according to provided instructions, as limiting instructions can only be considered effective tools for mitigating prejudice against an accused if a jury is presumed to understand and follow them. Chief Justice Dickson explicitly addressed the risk that juries might misuse evidence or disregard or misunderstand an instruction, acknowledging that "[j]uries are capable of egregious mistakes and they may at times seem to be ill-adapted to the exigencies of an increasingly complicated and refined criminal law". (11)
Despite these risks, the majority justified the presumption of jury competence in several ways. First, the majority reasoned that respect for legislative deference demands that until Parliament changes the jury system, courts should not "call into question the capacity of juries to do the job assigned to them". (12) Second, the majority stated that given the fundamental right to a jury trial in section 11(f) of the Charter, "it is logically incoherent to hold that juries are incapable of following the explicit instructions of a judge". (13) Third, the sociological studies on which the dissent in the Court of Appeal relied were found insufficient to overturn a presumption that juries act properly. (14) Fourth, the majority relied on the fact that, when given clear direction, juries are trusted to distinguish between proper and improper purposes in other areas of evidence, such as similar fact evidence and evidence of a confession by a co-accused in a joint trial. (15) Finally, the majority referred to other common-law countries to show that they maintain the same presumption, quoting the following from a US decision:
If we are to continue in our belief that a trial by a jury of 12 peers offers the fairest determination of guilt or innocence, then we must credit the jury with the intelligence and conscience to consider evidence of prior convictions only to impeach the credibility of the defendant if it is so instructed. (16) The majority's decision clearly underscores the belief that a jury will accurately apply the instructions provided to it by the trial judge. Without this belief, the majority's solution to the risk of prejudice caused by the introduction of an accused's criminal record cannot be presumed to be effective. The majority's justifications, however, rely not on observations about the inherent characteristics of a jury, but rather on policy concerns such as legislative deference, and on instrumental concerns such as the resulting impact on other areas of evidence law. The majority's language is revealing:
In my view, it would be quite wrong to make too much of the risk that the jury might use the evidence for an improper purpose. This line of thinking could seriously undermine the entire jury system. (17) The preservation of the presumption that juries act according to provided instructions rests on the serious disturbance to the Canadian criminal justice system that would result if courts acknowledged that juries might be disregarding or misunderstanding the instructions provided to them. Explicit acceptance of this concern in the highest court of Canada might throw doubt on all prior jury convictions.
It is worth noting that the majority in Corbett agreed with the dissent about preserving a residual discretion for the trial judge to exclude evidence of an accused's prior convictions in those unusual circumstances where introduction of such evidence may be so prejudicial as to deprive the accused of his or her right to a fair trial. (18) If juries consistently followed all instructions provided to them, a limiting instruction would logically mitigate any potential prejudice caused by evidence of even the most damaging or shocking prior conviction. The preservation of a residual discretion is an implicit acknowledgment by the majority that juries can be prejudiced in ways that instructions from the trial judge cannot overcome, and that there is a line beyond which juries are swayed by emotion or other flaws of human reasoning and cannot be presumed to follow instructions. Even though the majority in Corbett justified the presumption of jury competence on policy and instrumental grounds, it tacitly accepted that in some unusual cases, juries cannot entirely be trusted to apply the law as instructed.
III THE PRESUMPTION OF JURY COMPETENCE IN OTHER AREAS OF EVIDENCE LAW
Though most explicitly addressed in Corbett, the presumption that juries act according to provided instructions underlies many other areas of evidence law. Chief Justice Dickson in Corbett points to similar fact evidence and confessions made by a co-accused person in a joint trial as two such examples. (19) Another notable area where the implications of instructions in a jury charge have been emphasized is post-offence conduct evidence. To avoid misuse of post-offence conduct evidence in a case where the evidence is equally consistent with both the Crown's and defence's theories, the Supreme Court of Canada decided in R v Arcangioli (20) that a "no probative value" instruction ought to be given. (21) The purpose of such an instruction is to...