Stress trackers do indeed make us more stress-aware, but we hardly believe their message and prefer to rely on our own feelings. For her PhD research “Quantified stress: toward data-driven stress awareness“, Els Kersten looked at whether the feedback provided by a stress tracker helps us to become more aware of stress. Today – April 3 – she will obtain her PhD at the Eindhoven University of Technology (TU/e).

More and more often we see ‘Big Data’ (gathering a lot of information to make clever insights and predictions) also applied in the personal sphere: step and calorie counters, sleep quality and heart rate meters. With apps and smart wristbands, we can keep track of everything we want. ‘Self-tracking’ is what it is called. In her research, Kersten¬†looked at a relatively new possibility of self-tracking: the stress tracker.

“In the study, I had about 120 people perform a range of tasks of varying difficulty on a computer. Half of the participants were also continuously shown their heart rate charts on the screen, the other half were not. For each assignment, they had to indicate how much stress they had experienced. It is true that people’s own estimates of their stress level were more in line with what was happening in their bodies in the heart rate group than in the group that did not receive this information.

But a follow-up study showed that almost exactly the same effect could be achieved with fake feedback. Half of the participants were shown a graph that did not show their own heart rate. Here, too, the group with the graph began to make better estimates than the group without it. Kersten: “This surprising effect indicates that it is not so much the information in the feedback that makes us more aware, but rather the fact that we are encouraged by that feedback to listen better to our own bodies.”

Kersten also investigated to what extent feedback leads to insights about stress, such as finding out what stress-increasing activities are and what you can do to reduce stress. “That requires us to trust our tracker, to believe that it really knows how stressed you are – and even knows that better than you do. My research shows that people tend to believe themselves anyway. To this end, some 120 participants were presented with a graph when they submitted their declarations, sometimes with correct and sometimes incorrect information. It turned out that the participants rely much more on their own judgement than on the information provided when assessing their stress level.”

A similar result emerged from a field study in which 27 people were given a stress tracker for 3 weeks. “Many participants indicated that they did not trust the stress levels that the device showed. They also often thought that the information on the device and the time spent on it was not useful. The vast majority of the participants did not complete the three weeks. The group that did complete the period indicated that it did so out of a sense of duty.”

According to Kersten, this research shows on the one hand that stress tracking can be valuable for stress: “By being exposed to feedback about stress, we are encouraged to reflect and listen to our bodies better. On the other hand, the results emphasize how important it is not to assume that measuring is synonymous with knowing. Both insights contribute to a better understanding of how we can use technology to help people cope with stress.”