Various reasons have been put forward to justify this exclusion. One reason is that it creates undue suspicion against the accused and undermines the presumption of innocence [55] . Another is that tribunals of fact, particularly juries, tend to assume too readily that behavioural patterns are constant and that past behaviour is an accurate guide to contemporary conduct [56] . Similarly, "[c]ommon assumptions about improbability of sequences are often wrong" [57] , and when the accused is associated with a sequence of deaths, injuries or losses, a jury may too readily infer that the association "is unlikely to be innocent" [58] . Another reason for excluding the evidence is that in many cases the facts of the other misconduct may cause a jury to be biased against the accused [59] . In the present case, for example, once the H evidence was admitted, it would require a superhuman effort by the jury to regard the appellant as other than a person of depraved character whose uncorroborated evidence, whether or not he was guilty, could not be acted upon except where it supported the prosecution case. Functional reasons also play a part in excluding evidence of bad character. Trials would be lengthened and expense incurred, often disproportionately so, in litigating the acts of other misconduct; law enforcement officers might be tempted to rely on a suspect's antecedents rather than investigating the facts of the matter; rehabilitation schemes might be undermined if the accused's criminal record could be used in evidence against him or her [60] .
1. (1995) 182 CLR 461 at 512-513.
2. Perry v The Queen (1982) 150 CLR 580 at 593-594, per Murphy J; R v Boardman [1975] AC 421 at 451, per Lord Hailsham; Piragoff, Similar Fact Evidence (1981), p 4.
3. Cowen and Carter, Essays on the Law of Evidence (1956), pp 144-145; Imwinkelried, The Use Of Evidence Of An Accused's Uncharged Misconduct To Prove Mens Rea: The Doctrines which Threaten to Engulf the Character Evidence Prohibition, Ohio State Law Journal, vol 51 (1990) 575, at pp 581-582 ; Ligertwood, Australian Evidence, 2nd ed (1993), pp 81-82; Palmer, The Scope of the Similar Fact Rule, Adelaide Law Review, vol 16 (1994) 161, at p 169 .
4. Perry (1982) 150 CLR 580 at 594, per Murphy J.
5. Perry (1982) 150 CLR 580 at 594, per Murphy J.
6. R v Bond [1906] 2 KB 389 at 398, per Kennedy J; Piragoff, Similar Fact Evidence, (1981), pp 4-5; Cross on Evidence, 2nd Aust ed (1991), par 21145; Ligertwood, Australian Evidence, 2nd ed (1993), p 81.
7. See Cross on Evidence, 2nd Aust ed (1991), par 21150.