FACTOR is pleased to announce our next talk by Scarlett Varoose-Peer (FACTOR, LAEL), in partnership with PhonLab:

TITLE

The Risk of Data Contamination in (Forensic) Voice Identification: a Perception Experiment using Voice-mixed Speech Samples

ABSTRACT

Data contamination is a widely acknowledged phenomenon across many forensic disciplines. However, in an apparent single-speaker sample obtained from a multi-speaker recording, how could we establish whether that sample has been ‘mixed’ with other voices present in that original recording? This talk introduces ‘voice-mixing’ – a form of data contamination that specifically impacts voice identification analyses. In doing so, this talk details the design and results of a perception experiment in which 121 lay listeners were exposed to 21 audio samples created using the West Yorkshire Regional English Dataset (WYRED; Gold, Ross & Earnshaw, 2018): 6 were ‘authentic’ (i.e., non-voice-mixed) and 15 were ‘voice-mixed’. The voice-mixed samples ranged from low-to-high similarity speaker pairs. Using a 5-point Likert scale, listeners reported the extent to which they believed each sample to be voice-mixed/authentic. The results revealed that there was not a significant relationship between actual exposure to a voice-mixed sample and perceiving it as voice-mixed. However, on modelling the degree of similarity within the voice-mixed samples, this revealed a significant relationship: listeners were more likely to rate high-similarity voice-mixed samples as ‘authentic’ than they were for lower similarity samples. The results also revealed that several participant-intrinsic and participant-extrinsic factors impacted the perception of voice-mixed versus authentic samples. Taken together, I argue that data contamination- and specifically voice-mixing, poses a very real risk in (forensic) voice identification. In a climate of striving for trust in intelligence operations and the criminal justice system, it is time we start to address these risks.

TIME & PLACE

W07, 1500-1550, Tue 18th Nov 2025

In-person: County South B89

Online: Teams

Find information on how to get to campus here, and how to navigate campus buildings here.

FACTOR is pleased to announce a talk by Alice Paver (Cambridge), in partnership with PhonLab:

TITLE

Perceived voice similarity, voice quality and the telephone effect: an experiment

ABSTRACT

Voice quality (VQ) is considered a key speaker-specific feature for speaker comparison conducted by forensic phoneticians, but as audio samples for analysis are often of poor and/or mismatched quality (e.g. telephone vs. police interview), analysts must consider the potential effect of audio quality on perception of VQ which can affect expert assessments. Perceived voice similarity (PVS) is also a concern for experts, not just for speaker comparison but also when collecting earwitness evidence via voice parades. VQ is a phonetic correlate of PVS judgements by lay-listeners, and telephone transmission is known to reduce perceptual distance between voices, but the perceptual effect of reduced audio quality on specific VQ settings across multiple speakers is not yet known. An online experiment investigated the relationship between VQ and PVS in different audio quality conditions. This talk will discuss findings and their implications for our understanding of perceived voice similarity and the role voice quality plays in forensically relevant audio quality conditions.

TIME & PLACE

W04, 1500-1550, Tue 28th Oct 2025

In-person: County South B89

Online: Teams

Find information on how to get to campus here, and how to navigate campus buildings here.

FACTOR is pleased to announce our Week 3 discussion, which will be led by Dr Justin Lo:

TITLE

Public trust in digital data & evidence

ABSTRACT

For Week 3, we are planning to have a discussion on public trust in digital data and evidence. This is inspired by a few reports that I have recently come across, all broadly linked to this theme and with interesting commonalities, and I thought it would be worth having a think what the issues outlined in these reports mean for the forensic and security areas. I’ll present a brief summary in the beginning, but I also invite you to have a quick read (none of them are particularly lengthy):

1. CETaS report on UK public attitudes to national security data processing: Assessing human and machine intrusion (linked) (The report is long, but there is a good executive summary.)
2. Williams et al. (2026). Public perceptions of speech technology trust in the United Kingdom. Computer Speech & Language
3. Trust in Forensic Science Evidence (2024) Project Launch Event Report

TIME & PLACE

W03, 1400-1450, Thu 23rd Oct 2025

In-person: County South C89

Online: Teams

Find information on how to get to campus here, and how to navigate campus buildings here.

FACTOR is pleased to announce a special extra FACTOR event. This very last meeting of the 2024-2025 academic year is the rescheduled talk by Dr Christin Kirchhübel (Principal Consultant, Soundscape Voice Evidence):

TITLE

What’s the (copy)right way? Navigating legal issues around the input and output of large speech and language models

ABSTRACT

Large speech and language models present new challenges for existing copyright law: To what extent does developing these models pose copyright infringement risks? What is the copyright status of the outputs of these models? This talk addresses these two questions, highlighting some of the current conversations and legal cases in this sphere.

TIME & PLACE

W22, 1300-1350, Mon 28th Apr 2025

In-person: Cavendish Colloquium

Find information on how to get to campus here, and how to navigate campus buildings here.

FACTOR is pleased to announce our final talk of the 2024-2025 academic year by Dr Tharindu Ranasinghe (Computing, SPS):

TITLE
Offensive or Not? Are we doing offensive language detection in the correct way?

ABSTRACT
Offensive speech on web platforms is a persistent problem with wide-ranging impacts. There are many automatic content moderation systems that detect offensive content on web platforms. However, among many reasons why these tools fail to eliminate the problem is the reality that people often disagree on what is offensive.

In this talk, I will talk about how content moderation issues arise in political discussions, how machine and human moderators disagree on what is offensive when it comes to real-world social web political discourse and how content moderation research should address them. I will then present my broader vision of integrating this idea into other subjective natural language processing tasks.

TIME & PLACE

W18, 1500-1550, Thu 06th Mar 2025, Bowland North SR10. (Please note that this talk will not be streamed or recorded.)

Find information on how to get to campus here, and how to navigate campus buildings here.

FACTOR is pleased to announce our next talk in the 2024-2025 academic year by Ellen Roberts (LAEL, Lancaster University):

TITLE

Jingle jangle fallacies: observations and learnings from a replication of Biber (1988)

ABSTRACT

Multidimensional analysis (MDA) is a well-established method for the study of textual linguistic variation. It is a method that is often used for register analyses and has been suggested as a means of explaining authorship differences (Grieve 2023). However, the process of conducting an MDA is not straightforward and some replications of the method have failed to reproduce results from other studies (Lee 2000). Recent publications have provided ‘how-to’ guidance on conducting the MDA method across a range of software to try to clarify the methodological process (Egbert and Staples 2019). But how successful has this clarification been?

This talk outlines some of the learnings and pitfalls from an attempted replication of the MDA statistical method of choice, Factor Analysis, as part of my PhD research. This research draws on the psychological notion of jingle and jangle fallacies to explore possible misconceptions in the implementation of factor analysis, following Grieder and Steiner (2022).

More broadly, this presentation aims to demonstrate via this case study, the importance of methodological transparency and sensitivity across different statistical software used across the social sciences and in forensics research more widely.

TIME & PLACE

W15, 1500-1550, Thu 13th Feb 2025, Welcome Centre LT1 (A34). (Please note that this talk will not be streamed or recorded.)

Find information on how to get to campus here, and how to navigate campus buildings here.

FACTOR is pleased to announce our next talk in the 2024-2025 academic year by Dr Christin Kirchhübel (Principal Consultant, Soundscape Voice Evidence):

TITLE

What’s the (copy)right way? Navigating legal issues around the input and output of large speech and language models

ABSTRACT

Large speech and language models present new challenges for existing copyright law: To what extent does developing these models pose copyright infringement risks? What is the copyright status of the outputs of these models? This talk addresses these two questions, highlighting some of the current conversations and legal cases in this sphere.

TIME & PLACE

W14, 1500-1550, Thu 06th Feb 2025

Teams: Register here

In-person: Welcome Centre LT1 (A34)

Find information on how to get to campus here, and how to navigate campus buildings here.