The role of intonation for interrogative suggestibility

The detrimental consequences of suggestive witness manipulation have been frequently discussed in the literature. Notably, these discussions have been limited to the consequences of suggestive question types and interrogator conduct. This study is the first to investigate the influence of interrogator's intonation on interrogative suggestibility. Specifically, utilizing a modified German version of the forensic Gudjonsson suggestibility scale as dependent variable, we experimentally manipulated phrase-final contours (low vs. high) and accentuation of details (neutral vs. emphatic) in the questions of the interrogator in a student sample (N=88). Phrase-final falling intonation contours increased suggestibility both through suggestive questions and through negative feedback. In contrast, accentuation of selected details increased only the latter. The combination of both tonal patterns only partially influenced suggestive response behavior after the exposure to interrogative pressure. However, particularly the combination of phrase-final rising and neutral intonation consistently led to lowest interrogative suggestibility. Results are discussed in terms of their theoretical and applied implications for forensic contexts.