Research Data supporting "Pausing and the “Othello Error”: Patterns of Pausing in Truthful and Deceptive Speech in the DyViS Database"

The idea of detecting deception from speech is very attractive from a law enforcement perspective, yet research considering the possibility has yielded conflicting results, due to the practical difficulties in investigating the topic. Scientific research is yet to provide forensic linguistics with a reliable means of discerning lies from truths. The present study explores the relationship between truthfulness and pausing behaviour. Various aspects of the acoustics of pausing behaviour were investigated for Standard Southern British English in 30 mock police interviews from the DyViS database. A novel distinction was made between prescribed and unprescribed lies, to delineate a potential source of differences in the unscripted content of speakers’ untruthful responses. Among pause duration measures, statistically significant differences were found across all three response types (truth, prescribed lie, unprescribed lie) for response latency, between truths and lies for initial filled pauses, and between unprescribed lies and the other response types for silent pauses. For pause frequency measures, only internal filled pauses showed a statistically significant difference: truths differed from both types of lies, but prescribed lies did not differ from unprescribed lies. Theories of cognitive effort and attempted control are drawn on in accounting for these findings. The DyViS database provides recordings of 100 male speakers of Southern Standard British English, aged 18–25, from the University of Cambridge, undertaking four spoken tasks. The current investigation analyses recordings from Task 1, a mock police interview in which the participant assumes the role of suspect in a drug-trafficking crime. The participant views PowerPoint slides containing information about the crime scenario such as names of people and information about them, street names and venues, timing of events, etc. Most of the information is coloured black on the slides: these are details which the suspect is free to talk about. Some information is given in red: these details the suspect is required to lie about or conceal. Since interviewer style may affect speaker behaviour unpredictably (Dunbar, Jensen, Burgoon, Kelley, Harrison, Adame and Bernard 2015; Burgoon and Buller 2015), in the present study, the interviews undertaken by only one of the two DyViS interviewers (Gea de Jong) were used. Thirty interviews (DyViS Speakers 46–54, 56, 58–60, 62–65, 68, 69, 71, 73, 75–79, 84, 85, 87, 93) were analysed. The data were collected manually using recordings imported into Praat (Boersma and Weenink 2020). An Excel spreadsheet was used to collate the data and organise results according to response category (T, PL, UL). The present analysis, adopts a categorisation between truthful (T) and false answers, and whether the false responses were prescribed (PL) or not (UL). The T responses in the present study are all prescribed truths as the elicitation technique did not prompt a sufficient number of unprescribed truths for analysis. The distinction between prescribed and unprescribed lies may mirror the real-life circumstance of whether the suspect has prepared an alibi before police interrogation, with prescribed lies corresponding to responses based on their preprepared alibi, and unprescribed lies reflecting responses to unforeseen questions which have not been preconceived as part of their alibi. This provides a potential transferability between this novel experimental variable and real-life situations

Stereotyped accent judgements in forensic contexts: listener perceptions of social traits and types of behaviour

This paper reports the findings from a multidisciplinary and cross-institutional Economic and Social Research Council (ESRC) funded project called ‘Improving Voice Identification Procedures’ (IVIP). People harbour stereotypes about particular accents, and those judgements may be brought with them into the legal domain. Considering the potential consequences of accent judgements by witnesses and jurors, this study examines the relationship between characteristics and the likelihood of acting in certain criminal and non-criminal ways. Overall, 180 participants completed an accent judgement task, rating 10 regionally-accented voices on a range of traits and behaviours using a wider range of accents, behaviours and criminal offences than previous research. Results indicate that evaluations of perceived characteristics based on accent translate into evaluations of likely behaviours. The discussion explores the forensic implications of the relationships between perceived status and criminality, as well as between solidarity judgements and morally good actions. We emphasise the need for nuanced understanding of how accents are evaluated when it comes to different crime types.Isaac Newton Trus

Voice distinctiveness: an investigation of the role of speakers’ position in a population with respect to f0

The role played by f0 in listeners’ assessment of voice distinctiveness is investigated. In Experiment 1, listeners judged the (dis)similarity of low-, medium-, and high-pitched voices selected from an accent- and demographic-matched population. Listeners’ judge ments tended to cluster speakers together according to their position in a population distribution for f0, yet the tightness of these clusters varied, with members of the high-pitched group being consistently judged as most different from each other. This suggests that other phonetic dimensions are likely to be relevant as well as pitch. Experiment 2 collected similarity judgements of the same stimuli resynthesised with pitches shifted between the same low, medium and high positions in the population distribution. Results show that shifting the pitch of stimuli did not lead to a significant change in judgements, again indicating that more than pitch alone is driving the judgements phonetically. Implications for earwitness identification are discussed.This research was supported by the UK Economic and Social Research Council as part of the project Improving Voice Identification Procedures (IVIP), reference S/S015965/1. Additional funding was provided by the Isaac Newton Trust

Time to reflect on voices

Retention and Reflection Voice Parade Experimen

Time to reflect on voice parades: The influence of reflection and retention interval duration on earwitness performance.

Experiment-based voice parades often result in low hit-rates and high false-alarm rates. One contributing factor may be that the experimental procedures omit elements that might naturally occur in the memory formation process, such as the process of reflection. In Experiment 1 (N=180, F=92) we explored if a post-encoding reflection manipulation, compared to a simple attention control task, prior to a five-minute retention interval would improve identification performance. In Experiment 2 (N=180, F=93), we explored how the effects of this manipulation might change when the retention interval was 24-hours. The results show that the inclusion of a reflection manipulation did not meaningfully improve performance in either experiment. Importantly, we found no meaningful difference in performance when directly comparing the two retention interval durations. We consider theoretical explanations for these results and discuss implications for the design and validity of earwitness voice parade studies

Time to reflect on voice parades: The influence of reflection and retention interval duration on earwitness performance

Publication status: PublishedAbstractExperiment‐based voice parades often result in low hit‐rates and high false‐alarm rates. One contributing factor may be that the experimental procedures omit elements that might naturally occur in the memory formation process, such as the process of reflection. In Experiment 1 (N = 180, F = 92) we explored if a post‐encoding reflection manipulation, compared to a simple attention control task, prior to a five‐minute retention interval would improve identification performance. In Experiment 2 (N = 180, F = 93), we explored how the effects of this manipulation might change when the retention interval was 24‐h. The results show that the inclusion of a reflection manipulation did not meaningfully improve performance in either experiment. Importantly, we found no meaningful difference in performance when directly comparing the two retention interval durations. We consider theoretical explanations for these results and discuss implications for the design and validity of earwitness voice parade studies.</jats:p

Identifying unfamiliar voices: the influence of sample duration and parade size.

Voice identification parades can be unreliable due to the error-prone nature of earwitness responses. Home Office guidelines (2003) recommend that voice parades should consist of nine-voices, each played for 60-seconds. This makes parades resource-consuming to construct. In the present paper we conducted two experiments to see if voice parade procedures could be simplified. In Experiment 1, we investigated if reducing the duration of the voice samples on a nine-voice parade would negatively affect performance. In Experiment 2, we first explored if the same sample duration conditions used in Experiment 1 would lead to different outcomes if a six-voice parade were used. Following this, we investigated if there were any difference in identification performance based solely on whether a nine-voice (Experiment 1) or six-voice (Experiment 2) parade was used. Overall, the results suggest that voice durations can be safely reduced without disrupting listener performance. Performance on target-absent parades – which simulate an innocent suspect being apprehended – were at chance-levels in both parade sizes, but the increased number of foils in the nine-voice parade offers increased protection to an innocent suspect by virtue of statistical probability. Thus, we argue that the Home Office guidelines recommending a parade with nine-voices should be maintained

Stimuli

Stimuli and video files for the perception experimen

Data Processing Pipeline

We developed a set of praat script to measure responses latencies in the voice recordings generated with the internet-based cued-shadowing task