Connected watches and privacy: risks, dangers and data protection

The issue

While devices such as wearable activity trackers or connected watches contribute to a better quality of life, they also raise serious privacy issues. When you wear one of these devices, you leave behind a huge amount of personal data that companies like Google can store and use later on without your knowledge and for their own benefit.

Why it’s important

The use of a connected watch represents a real risk to privacy. Personal information that can predict an individual’s psychological profile can be misused by the companies that collect it. As in the case, for example, of the Cambridge Analytica scandal, where this British firm exploited the personal data of millions of Facebook users in order to promote the election of Donald Trump.

What our researchers have to say:

Funded by the SNSF, an empirical study was conducted for the first time on this topic by researchers at HEC Lausanne – PhD student Noé Zufferey, Prof. K. Huguenin and Prof. M. Humbert, and their co-author Prof. Romain Tavenard from the University of Rennes 2. It showed a significant correlation between the data from the connected watches and the personality traits of an individual.

The authors first conducted a personality test on more than 200 people. They then equipped them with a connected watch for four months. By collecting data such as number of steps, heart rate, activities performed, or sleep time, and comparing it to the results of psychological tests previously conducted, the study was able to establish how this physiological data from connected devices could be used to predict a person’s psychological profile.

PhD student in the Department of Information Systems at the Faculty of HEC (UNIL), Noé Zufferey and his co-authors have established that personality traits such as openness, extraversion and emotional stability can be predicted using this data extracted from connected watches. “For example, we found that step count plays a key role in assessing extraversion, as does emotional stability, where sleep time is also an indicator. Heart rate is also an indicator of an individual’s level of openness.

He says: “These results show that users who share their data on applications such as Facebook are unknowingly putting sensitive personal data in the hands of the companies that manage them.”


In the future, the researchers plan to work on solutions to minimize the risk of losing personal data to a third party. For example, informing people how to revoke their sharing, or helping the public to make good use of connected tools and to monitor the transmission of their private information.

Scientific papers :

N. Zufferey, M. Humbert, et K. Huguenin, HEC Lausanne et Romain Tavenard, University of Rennes 2:  “Watch your Watch: Inferring Personality Traits from Wearable Activity Trackers” In Proceedings of the USENIX Symposium on Security (USENIX Security), 2023.

Zufferey Noé, Salehzadeh Niksirat Kavous, Humbert Mathias, Huguenin Kévin,  “Revoked just now!” Users’ Behaviors Toward Fitness-Data Sharing with Third-Party Applications Published 01.23.

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