Verifiable information in truthful statements: do interview context and language proficiency matter?

We investigated the frequency of verifiable information in people’s truthful accounts of recent life events and whether its frequency varies within the interview context and language proficiency. Participants reported their activities from 2 pm to 6 pm the previous day and were randomly assigned to either neutral (n₁ = 50, n₂ = 47) or alibi interview conditions (n₁ = 48, n₂ = 48). In Study 1 (N = 98), participants wrote their accounts in their second language, English, while in Study 2 (N = 95), participants wrote their statements in their native language, French. On average, truthful accounts contained 42 (95% CI [37.2, 46.84]) and 43 (95% CI [35.99, 50.03]) verifiable details, as well as 34 (95% CI [28.3, 40.62]) and 35 (95% CI [31.41, 40.13]) non-verifiable details, respectively. Participants included proportionally more verifiable than non-verifiable information in English (M =.56, 95% CI [.51,.61]) and French reports (M =.54, 95% CI [.49,.58]). No significant differences were found between the neutral and alibi interview groups in either study (ts_Study1 < 1.04, ps >.31; ts_Study2 < 1.14, ps >.26). Additionally, no significant differences were observed between the non-native (Study 1) and native (Study 2) speakers in terms of (non-)verifiability (ts <.78, ps >.44). These findings suggest that the verifiability of truthful reports is not influenced by the interview context or language proficiency.