Surveys that measure self-report are a workhorse in psychology and the social sciences, providing a vital window into beliefs, attitudes and emotions, both at the level of groups and individuals. The validity of self-report data, however, is an enduring methodological concern, with self-reports vulnerable to a range of response biases, including (among others) the risk of social desirability bias in which, rather than responding honestly, participants answer questions in a way that they believe will be viewed favourably by others. One proposed solution to socially desirable responding is the so-called Bayesian Truth Serum (BTS), which aims to incentivise truthfulness by taking into account the relationship between an individual’s response and their belief about the dominant (or most likely) response given by other people, and then assigning a high truthfulness score to answers that are surprisingly common.

 

Although valid in theory (under a variety of assumptions), questions remain regarding the empirical utility of the BTS. One area of concern is participants’ uncertainty regarding incentives for truth-telling – if participants don’t understand the extent to which telling the truth is in their own interests (or they don’t believe that it matters) then the validity of the BTS is undermined. In the current study, Neville and Williams (2024) aim to test the role of clarifying incentives, particularly for addressing social desirability bias when answering sensitive questions. The authors will administer an experimental survey design including sensitive questions, curated from validated scales, that are relevant to current social attitudes and sensitivities (e.g. “Men are not particularly discriminated against”, “Younger people are usually more productive than older people at their jobs”). Three groups of participants will complete the survey under different incentive conditions: the BTS delivered alone in standard format, the BTS with an interim bonus payment that is awarded to participants (based on their BTS score) half-way through the survey to increase certainty in incentives, and a Regular Incentive control group in which participants receive payment without additional incentives.

 

The authors will then address two questions: whether the BTS overall effectively incentivises honesty (the contrast of BTS alone + BTS with interim payment vs the Regular Incentive group), and whether interim payments, specifically, further boost assumed honesty (the contrast of BTS alone vs BTS with interim payment). Regardless of how the results turn out, the study promises to shed light on the effectiveness of the BTS and its dependence on the visibility of incentives, with implications for survey design in psychology and beyond.

 

The Stage 1 manuscript was evaluated over two rounds of in-depth review. Based on ​detailed responses to reviewers’ and the recommender’s comments, the recommenders judged that the manuscript met the Stage 1 criteria and therefore awarded in-principle acceptance.​​​

 

 

Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI-RR-friendly journals:

 

 

Neville, C. M & Williams, M. N. (2024). Does Truth Pay? Investigating the Effectiveness of the Bayesian
Truth Serum with an Interim Payment: A Registered Report. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/vuh8b