Purpose: This study examined how the language of eyewitnesses (native vs. non-native) and their perceived credibility influence the interrogation questions posed to them.Method: In a previous study (Raver et al., Frontiers in Psychology, 2023, 14, 1240822), participants, assuming the role of interrogators, watched either a native or non-native speaking eyewitness testify and were then asked to formulate interrogation questions to gather more information, as well as rate the witness’s credibility. In the present study, a new set of participants (N = 207) evaluated a subset of these interrogation questions in terms of (1) how leading they were, (2) whether the interrogator cast doubt on something the witness had said and (3) how open-ended they were. The moderating role of witnesses’ perceived credibility on question framing was also examined.Results: Results showed no main effect of language (native vs. non-native) on any question type. For native speakers, lower (vs. higher) credibility led to more expressions of doubt. For non-native speakers, credibility levels (high vs. low) had no effect on question framing.Conclusion: These findings highlight complex patterns in interrogation questioning that vary by witness language and perceived credibility, revealing a critical area for further exploration to mitigate potential cross-linguistic biases. We discuss the study’s limitations and advocate for future research in diverse legal contexts to ensure fairness and uphold the integrity of witness testimonies across languages.

Non-verbal behaviour, such as facial expressions and body language, plays a critical role in assessments of witnesses’ credibility that inform legal decisions in cases involving crime. While prior research has primarily focused on associations between non-verbal cues and deception, this study investigates the relation between non-verbal cues and recall memory accuracy in honestly reported mock eyewitness testimonies. Using a sample of 36 video-recorded eyewitness testimonies about a violent crime (n = 680 statements), we examined whether non-verbal cues were associated with statement accuracy (correct vs. incorrect), witness credibility as rated by independent observers, and witnesses’ self-reported confidence. Additionally, we explored whether these associations differed for native vs. non-native speaking witnesses. Results revealed no associations between non-verbal cues and statement accuracy or perceived credibility. Furthermore, while non-native speakers were perceived as less credible, these perceptions were not related to non-verbal cues. Our findings contradict common beliefs by showing that non-verbal behaviour is not reliably related to accuracy or perceived credibility in eyewitness testimonies, highlighting the need for caution in their use in high-stakes legal contexts.

Eyewitness testimony plays a critical role in legal proceedings. Yet, its usefulness hinges on both the reliability of the information from the witness, and how that information is perceived. When eyewitnesses testify in a non-native language, language barriers may shape not only what is communicated but also how their testimony is interpreted and judged. This thesis investigates whether testifying in a non-native versus native language affects the reliability and perceived credibility of honestly reported eyewitness testimonies. Across three empirical studies, I examined how language influences memory accuracy, suggestibility, the confidence-accuracy relation, observer-rated credibility, investigative questioning practices, and non-verbal behavior. Study I comprised two experiments. In Study Ia (N = 121), mock eyewitnesses provided testimony in either a non-native (English; n = 61) or their native (Swedish; n = 60) language after viewing a mock-crime video. Testimonies accuracy and suggestibility were measured, and the confidence-accuracy relation computed. Witnesses also rated their own credibility and cognitive effort when giving the testimony. No differences emerged between witness groups in accuracy, suggestibility, cognitive effort, or self-rated credibility. However, in line with the confidence-accuracy relation, witnesses were more confident overall in correct than incorrect details. Importantly, non-native speakers reported significantly lower confidence than native speakers, despite being equally accurate. In Study Ib (N = 202), mock interrogators were randomly assigned to assess either a non-native or native video-recorded testimony for credibility and to formulate follow-up interrogation questions. The interrogators judged non-native speakers as less credible than native speakers. Study II examined the interrogation questions (N = 806) formulated in Study Ib with respect to how leading, doubt-casting, and open-ended they were. No differences emerged in the types of questions posed to non-native versus native speakers. However, when interrogators perceived a witness as more credible, they posed fewer questions casting doubt, but this effect was only observed for native-speaking witnesses. Study III examined whether the presence (vs. absence) of a set of predefined non-verbal cues predicted the accuracy of 680 statements, witnesses’ self-reported confidence, and observer-rated credibility. None of the cues reliably predicted these outcomes, challenging assumptions about the diagnostic value of non-verbal cues in legal contexts. Together, this thesis provides converging evidence that language barriers can introduce bias in how eyewitness testimony is received and acted upon, not due to differences in testimony reliability, but due to how the testimonies are perceived in terms of credibility. The findings underscore the need for legal systems to better account for challenges placed on non-native speakers and to adopt practices that promote more fair credibility assessments.

Rape victims often face secondary victimization when interacting with the legal and healthcare systems, a risk that is exacerbated by the attitudes and practices of the professionals they encounter. This study, drawing on responses (N = 237) from police employees, prosecutors, and healthcare personnel, aimed to investigate rape victim treatment from the perspective of these professionals. Our investigation was two-fold: through a web survey, we first examined how professionals’ beliefs in a just world, acceptance of rape myths, and demographic factors influence their estimations of false reporting and trust in the justice system. We then used open-ended questions to identify perceived barriers, problematic practices, and areas for improvement within their professional roles and the overall system handling rape cases, providing both quantitative and qualitative data. Prosecutors and healthcare professionals reported significantly lower levels of estimations of false reports than police, with no significant difference between the two; additionally, prosecutors displayed the highest trust in the legal system, significantly greater than both police and healthcare professionals, whereas no significant difference was found between healthcare professionals and police. Overall, the professionals requested more specific knowledge on how to treat victims of rape and identified several perceived barriers (e.g. lack of resources, deprioritizing, and legislation) and problematic practices (e.g. interview practices and medical examination practices) that may cause secondary victimization. Practical implications for meeting and treating rape victims are discussed.

We examined whether an eyewitness memory accuracy and susceptibility to suggestions were affected by whether the testimony was given in a native or non-native language. Results showed no effects of language on memory accuracy or suggestibility. Witnesses testifying in a non-native vs. native language were less confident in their memory.