The accused cannot call witnesses to show that he has engaged in specific acts demonstrating his good character. This is to avoid mini-trials into those specific claims. Instead, the common law allows the compendious and concise technique of calling reputation witnesses. Witnesses who know the accused and are familiar with her reputation because they share a relevant circle of acquaintances with her are permitted to testify that her reputation is good.170The reputation testified to must be relevant, be it for morality in a sexual offence case,171peacefulness in a violence case, or honesty in a dishonesty prosecution.
It has long been established that a character witness must confine himself to the community’s perceptions of the accused, and cannot express his or her own opinion about the accused’s character.172Occasionally courts ignore this limitation. In R. v. Millar, for example, without discussing its earlier decisions, the Ontario Court of Appeal held that a trial judge erred by not directing the jury properly in a baby-shaking case as to how it could use the personal opinions expressed by the family members, friends, and neighbours of the accused that he was a calm, gentle, caring, thoughtful, and nurturing person.173In some cases expert witnesses may be allowed to testify that the accused has some distinctive characteristic that would make it less likely
that the accused committed the offence. "Reliable" expert evidence of this type would be admissible if "the trial judge . . . [is] satisfied, as a matter of law, that either the perpetrator of the crime or the accused has distinctive behavioural characteristics such that a comparison of one with the other will be of material assistance in determining innocence or guilt."174Most attempts by accused persons to lead evidence of this kind have failed because behavioural science tends not to provide reliable correlations between character types and incapacity to commit particular kinds of crime.175
The accused can assert his good character when testifying. In Morris v. R., for example, the accused advised the jury that he had never been convicted or even arrested.176The accused is even permitted to relate specific acts that suggest he is not the kind of person to commit the of-fence. In R. v. Samuel, the accused, charged with larceny, testified that he twice found property and returned it.177When an accused person asserts his good character in either of these ways, even during cross-examination, he will be taken to have put his character in issue, opening the door for the Crown to lead rebuttal evidence showing the accused is not of good character. The...