The role of intonation for interrogative suggestibility

Abstract

SummaryThe 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). Phrasefinal 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 phrasefinal rising and neutral intonation consistently led to lowest interrogative suggestibility. Results are discussed in terms of their theoretical and applied implications for forensic contexts. KEYWORDSGudjonsson suggestibility scale, interrogative suggestibility, intonation

Interrogator intonation and memory encoding performance

“…In order to gauge the potential influence of intonation during interrogation, participants’ memory performance needed to be ascertained. To this end, we employed the German version of the GSS-1, the forensically relevant version of the GSS (GGSS-1; [4]) consisting of a short story of a robbery broken down into 40 distinct items (Table 2). The Kiel University Institute of Phonetics and Digital Speech Processing produced a high-quality digital natural voice recording of four versions of the GGSS-1 story that differed with respect to their pitch curve and/or the auditive prominence of a few words but not in content.…”

“…Accordingly, from a legal psychological perspective, it has been only recently demonstrated that phrase-falling intonations (indicating claims/facts rather than questions) on the interrogator’s side contributed to increased interrogative suggestibility (i.e. “the extent to which, within a closed social interaction, people come to accept messages communicated during formal questioning, as the result of which their subsequent behavioral response is affected”[3], p. 84) in interviewed participants during the recall phase of more complex verbal information [4]. However, it remains an open empirical question whether the influence of intonation comes into effect as early as in the encoding phase of verbally presented episodes.…”

“…Based on these notions, it is conceivable that the influence of intonation might be extended even before the actual interrogation process [4]. After all, the presentation of the story (at least in case of the GSS) or an interrogees’ prior testimony is already a part of the communicative exchange between interrogator and interrogee.…”

“…The following explanations are based on the contour-based Kiel Intonation Model (KIM, [19]). The KIM was selected because prior research in legal psychology has corroborated its applicability to explain interrogative suggestibility ([4]).…”

“…As intonation plays a role during the recall phases after suggestive interrogation [4], we sought to explore a possible earlier impact of intonation on memory performance as early as in the encoding phase. To this end, we aimed to analyze intonation effects in two experiments: Experiment 1 focused on the recollection of the given information as a whole (i.e.…”