證詞可信度與論罪科刑：臺灣國民法官如何評價不同年齡與信心程度的證人

Abstract

臺灣自 2023 年起施行國民參與刑事審判制度（簡稱國民法官制度）。隨著制度上路，近期亦逐漸出現涉及兒童證人參與之國民法官案件。本研究以網路問卷呈現一起模擬國民法官案件，並以 3×3 之受試者間設計操弄證人年齡（8、 16、 30 歲）與其對證詞的信心程度（高／中性／低），檢驗兩者對臺灣一般民眾在證詞可信度評價、罪名判定與量刑之影響。研究共納入 351 份樣本，以二元羅吉斯迴歸分析罪名判定，並以二因子變異數分析檢驗量刑與可信度評價。結果顯示，證人年齡與其信心程度對罪名判定與量刑皆未呈現顯著影響。然，在證詞可信度的評價上，青少年證人在認知能力評價與誠實性評價上皆高於兒童與成人。另一方面，以證詞的信心程度而言，中性語氣相較於高、低信心版本獲得最高的可信度評價。整體而言，本研究顯示證人特徵能影響其可信度評價，卻未見於罪名與量刑判定之差異；一落差所涉及之決策依據與機制，仍有待後續研究進一釐清。

Since 2023, Taiwan has implemented the citizen judge system, and cases involving child witnesses have begun to appear. Using a simulated citizen judge case presented in an online survey, this study examined whether witness age and expressed confidence influence lay evaluations and legal decisions. A 3 × 3 between-subjects design manipulated witness age (8, 16, 30 years) and testimony confidence (high, neutral, low) among 351 participants. Charge decisions were analyzed with binary logistic regression, and credibility ratings and sentencing were analyzed with two-way ANOVAs. Neither witness age nor confidence affected charge selection or sentencing. In credibility judgments, however, testimony from a 16-year-old witness received higher ratings of both cognitive ability and honesty than testimony from an 8-year-old child or a 30-year-old adult, and the neutral-confidence version was rated as most credible. Overall, witness characteristics shaped subjective credibility evaluations but did not translate into differences in charge or sentencing decisions, suggesting a potential gap between evaluation and formal legal decision-making that warrants further study.