Do legal professionals make more rational decisions than nonprofessionals? The biasing effect of the number of verdict-alternatives on conviction rates.

OBJECTIVE: influence conviction rates, the decision making is distorted-an effect we term "N-verdict bias." We investigated the extent to which professional legal decision-makers are vulnerable to this bias. HYPOTHESES: We expected the N-verdict bias to arise among both professionals and nonprofessionals, but to be of lower magnitude among the former. METHOD: = 1,934) on participants with varying levels of legal expertise: bar disciplinary-panel adjudicators, practicing lawyers, law students, and laypeople. In Studies 1-5, participants rendered a verdict on a fictitious murder case, under two- versus three-verdict conditions. Study 6 tested whether receiving instructions about the beyond-reasonable-doubt standard eliminated the bias. Study 7 ascertained the internal confidence-threshold participants deemed necessary for conviction under two- versus three-verdict conditions. RESULTS: if guilt were proven beyond-reasonable-doubt. The confidence-threshold required for conviction did not vary significantly between the two conditions. CONCLUSIONS: Defendants are less likely to be convicted in a three-verdict system, making the number of verdict-alternatives another source of bias in legal decision making that legal expertise does not immunize against. (PsycInfo Database Record (c) 2026 APA, all rights reserved).