Psychological biases in judicial decision-making: examining the influence of cognitive heuristics, emotional responses, and case framing

2258 Judicial decision-making is expected to involve reasoning and reasoned evaluation which is based on evidence and legal principles, but legal information might be interpreted in a way influenced by psychological processes. Judicial decision-making is expected to involve reasoned evaluation based on evidence and legal principles, but such judgments may also be influenced by psychological processes. In this study, judicial decision-making was operationalised as participants’ responses to standardized legal decision vignettes that simulated core features of legal judgment rather than actual courtroom decisions. The psychological factors have been investigated in isolation by previous research and usually in the presence of judges or in a limited task context; this study investigates these factors as a group in a controlled vignette design. The recruitment was done using a non-probability sampling process (i.e., convenience sampling) involving 240 participants (107 law students and 133 general adult participants) from the UK. Descriptive statistics, reliability analysis, multiple regression, independent-samples t-test, and one-way ANOVA were used in the study. The internal consistency was satisfactory for all four study constructs, with Cronbach's alpha values ranging from 0.761 to 0.887. The model accounted for 34.2% of the variance in judicial decision-making. Framing of cases was the strongest significant predictor (β = 0.604, p < 0.001), whereas the emotional responses had a significant negative correlation with judicial decision-making (β = −0.188, p = 0.009). Cognitive heuristics were not a significant predictor (β = 0.045, p = 0.577). Judicial decision-making also differed significantly between law students and general adults, t(238) = −2.258, p = 0.025, and across age groups, F(4,235) = 4.518, p = 0.002. Among UK law students and general adult participants, case presentation and emotional-response scores were associated with judicial decision making, whereas heuristic-response scores were not significant in the multivariable model.