§1. Overview
Criminal defendants, victims, and witnesses all have certain behavioral attributes. These attributes include their various character traits, their personal histories of specific past conduct, and, when considered as members of some identifiable group (e.g., child molesters, rape victims), certain common behavioral patterns. Proof of these behavioral attributes can be divided into three categories of evidence: (1) "character" evidence, (2) "profile" evidence, and (3) "syndrome" evidence. Despite its apparent relevance, there is a certain level of distrust in the law in admitting behavioral evidence. First, behavioral evidence turns the jury's focus away from evidence that more directly addresses the actual conduct the defendant is charged with, and instead focuses the jury's attention on evidence that only indirectly helps establish the truth of the matters charged. Second, there is the danger that jurors may give some behavioral evidence more significance than it logically deserves. And finally, in the case of profile and syndrome evidence, the scientific basis for the evidence and how the jury will use it are questionable. Thus, although a fundamental principle of the Evidence Code is that relevant evidence is ordinarily admissible, the Code and its judicial interpretations place a variety of significant limits on the use of character and related evidence. To navigate these limits and properly analyze the admissibility of behavioral evidence, a practitioner should follow three steps: (1) determine the category of the behavioral evidence in question (i.e., character, profile, or syndrome evidence), (2) determine the specific purpose for which the evidence is being presented, and (3) determine the type of evidence that can be used to prove the behavioral evidence.
§1.1. Categories of behavioral evidence. The first step in analyzing the admissibility of behavioral evidence is to determine which category of behavioral evidence is in question. The three categories of behavioral evidence are the following:
1. Character evidence. Character evidence generally describes evidence of someone's personality traits or propensities of a praiseworthy or blameworthy nature. Evidence, character evidence, Black's Law Dictionary (11th ed. 2019). Character evidence may describe a person's character in general terms (good or bad character), or it may describe a specific character trait, such as truthfulness or untruthfulness, honesty or dishonesty, prudence or recklessness, or peacefulness or aggressiveness. See 1 Witkin, California Evidence (5th ed.), Circumstantial Evidence §40.
2. Profile evidence. Profile evidence generally describes common behavioral patterns of a particular type of criminal perpetrator, such as a child molester or a drug dealer. See People v. Prince (2007) 40 Cal.4th 1179, 1226; 1 Witkin, California Evidence (5th ed.), Circumstantial Evidence §30.
3. Syndrome evidence. Syndrome evidence generally describes common behavioral patterns of victims of a particular kind of offense, such as sexually molested children or persons abused by an intimate partner. See People v. Brown (2004) 33 Cal.4th 892, 904-06; People v. Bledsoe (1984) 36 Cal.3d 236, 247-48; Jennifer K. v. Shane K. (1st Dist.2020) 47 Cal.App.5th 558, 585.
...Note Evidence of habit and custom is to be distinguished from other
