What does Rule 404(b) prohibit, and what are permissible non-propensity purposes for other acts?

• A. Propensity to commit crimes.
• B. Motive, intent, knowledge, opportunity, plan, identity, or absence of mistake.
• C. Evidence of character to prove conduct in conformity.
• D. Prior convictions.

Answer: (B)

Rule 404(b) bars using evidence of other crimes or acts to prove a person’s character in order to show they acted in conformity on the charged occasion. But it allows such evidence when it’s offered for non-propensity purposes—reasons other than showing character or propensity. The permitted non-propensity purposes include motive, intent, knowledge, opportunity, plan, identity, or absence of mistake. Each of these shows something about why or how the conduct happened, not that the person is the kind of person who commits crimes. For example, proving a motive explains why the defendant would commit the act; proving identity helps link the defendant to the act; proving absence of mistake suggests the act wasn’t accidental. Rule 403 may still require balancing to keep the evidence from being unduly prejudicial. So the best answer is the list of permissible non-propensity purposes: motive, intent, knowledge, opportunity, plan, identity, or absence of mistake.