Our findings show that people do not only think about their own privacy but also about the potential harm their data sharing could cause to others. We also find that simple, scalable interventions such as highlighting social norms can meaningfully shift disclosure decisions. This suggests that norm-based and transparency-enhancing features could play an important role in future digital consent frameworks.
Dr Leonie Gerhards, Senior Lecturer in Economics at King’s Business School
18 September 2025
People less willing to share personal data when it risks others' privacy
Reminders about social norms can make people less likely to overshare personal data.
New research from King’s Business School has found people are less willing to sell their personal data if doing so could compromise the privacy of others.
The study, published in the Journal of Economic Psychology was co-authored by Leonie Gerhards, alongside Tim Friehe from University of Marburg and Franziska Weber from Erasmus University Rotterdam. It used a controlled experiment to test how individuals value personal data when sharing it also creates risks for others. Participants were asked how much money they would accept to disclose information in scenarios where another person’s privacy or financial outcome might be affected.
On average, participants demanded around €0.60 more to disclose data that could create an expected loss of €2 for their peer, whilst they did not differentiate between cases where harm was certain and cases where there was only a 50% chance of harm. The researchers suggest this points to rule-based moral reasoning rather than cost–benefit calculations in decisions about privacy.
The experiment also tested whether social nudges could influence behaviour. Providing information about a peer’s disclosure decisions influenced 27% of participants, while prompts encouraging reflection on social norms reduced willingness to sell personal data by between 10-12.5%.
The findings show that people consider not only their own privacy but also the potential harm that disclosing information could cause to others. Building on these insights, the authors discuss potential policy implications. For instance, digital consent frameworks could incorporate simple interventions to support more mindful data-sharing decisions. Examples include prompts that highlight how sharing may affect others (“Sharing this may compromise others’ privacy”) or show prevailing behavioural norms (“Most users prefer not to share this kind of data”).
The researchers suggest that combining such nudges with clearer communication about when data sharing also impacts others could be valuable from a user perspective. They suggest that norm-based and transparency-enhancing features could help people make more informed choices and reduce harmful spillovers in an increasingly data-driven economy.
The study, Keep them out of It! How information externalities affect the willingness to sell personal data online, is published in the Journal of Economic Psychology.
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Senior Lecturer (Associate Professor) in Economics