The Unexpected Questions Approach as a veracity assessment tool

 Applications are invited for a fully-funded three year PhD to commence in October 2025. 

The PhD will be based in the Faculty of Science and Health within the School of Psychology, Sport and Health Science, and will be supervised by Dr Aldert Vrij, Dr Haneen Deeb and Dr Ronald P. Fisher.

Candidates applying for this project may be eligible to compete for one of a small number of bursaries available. Successful applicants will receive a bursary to cover tuition fees at the UK/EU rate for three years and a stipend in line with the UKRI rate (£19,237 for 2025/26). Bursary recipients will also receive a contribution of £1,500 per year towards consumables, conference, project or training costs.

Costs for student visa and immigration health surcharge are not covered by this bursary. For further guidance and advice visit our international and EU students ‘Visa FAQs’ page.

Guilty suspects expect that they will be interviewed by the police and thus prepare responses to questions that they think may be asked. (Clemens et al., 2011). This preparation benefits lie tellers, because veracity differences are less pronounced in prepared than in spontaneous lies (DePaulo et al., 2003). However, preparation has a limitation because lie tellers cannot know which questions will be asked. Investigators can exploit this limitation by asking questions that lie tellers in all likelihood have not anticipated, but that for truth tellers are as easy to answer as the other questions (Monaro et al., 2017; Warmelink et al., 2019). 

Previous research has shown that some questions yield larger veracity effects than other questions. Effective questions include questions about spatial information (Vrij et al., 2019) and planning (Knieps et al., 2013; Mac Giolla et al., 2015). Self-reports in the experiments in which these questions were asked showed that lie tellers found them unexpected making researchers conclude that the unexpectedness of the questions caused the effect. However, this conclusion is premature, because the results in these experiments do not necessarily mean that the unexpectedness of the questions caused the veracity effects. The alternative explanation is that questions such as spatial and planning questions are types of questions that are particularly challenging for lie tellers to answer (see Soufan, 2011). 

This project will examine, through three experiments, which of these two explanations is responsible for the effect. Truth tellers and lie tellers will be interviewed answering questions they have in all likelihood expected to be asked and unexpected questions. Half of the participants will be given the set of questions prior to the interview with the chance to prepare the answers to them. The other half will be asked to prepare themselves for the interview but will not be given the sets of questions. 

How to apply

If you have any project-specific questions please contact Dr Aldert Vrij (aldert.vrij@port.ac.uk), quoting the project code.

When you are ready to apply, please use the online application form of the respective project on our PhD scholarships page. Please note that email applications are not accepted.

Make sure you submit a personal statement, proof of your degrees and grades, details of two referees, proof of your English language proficiency and an up-to-date CV.  Our ‘How to Apply’ page offers further guidance on the PhD application process.

If you want to be considered for this funded PhD opportunity you must quote project code PSH50190125 when applying.