Microsoft researchers have developed a bra-mounted sensor system that measures boob sweat and heart activity in order to detect emotional triggers for overeating.

The research is based on the idea that people eat not just when they are hungry but also for a host of emotional and habitual reasons. The goal was to provide a system that could intervene before the person turns to food for emotional support.

Microsoft researchers teamed up with colleagues from the University of Rochester and the University of Southampton to develop a range of interventions that go a step further than activity trackers such as FitBit and Nike's Fuelband. In their paper, the researchers mention other systems that have been developed that include heart rate monitors, earpieces to track chewing and swallowing, and augmented reality glasses to capture the food consumed.

But the team wanted to have a system of wearable sensors that measure electrodermal activity (EDA), which is essentially the amount of sweat on a person's skin; and electrocardiogram (EKG) data. Both are useful for gauging emotions. The sort of scenario the system needed to be able to deal with was as follows:

"Sally has been home from work for a few hours, and she ﬁnds herself rather bored. An application on Sally's mobile phone has also detected that she is bored by reading her physiological state through wearable sensors. Since this mobile application has previously learned that Sally is most susceptible to emotional eating when she is bored, the application provides an intervention to distract Sally and hopefully prevent her from eating at that moment."

This means that the application needed to be aware of Sally's emotional eating patterns, it needed to be able to detect different emotions through machine learning and it also needed to determine how to intervene while making sure it didn't become an annoyance to the user.

These three elements were explored through three separate studies. The first involved building an application called EmoTree to gather data about emotional eating patterns. A mobile app allowed users—all of whom self-identified as emotional eaters—to log their mood and food intake. There were reminded via text to log emotion every hour, at least ten times per day. This allowed researchers to build up an image of the participants' emotional states throughout the day. The study found that there were lots of different emotional triggers for eating, but generally there were fewer "eating events" when users felt calm or serene. As a consequence, the researchers proposed intervening when people felt stressed with some breathing exercises.

The second area of study sought to assess how useful the proposed breathing exercises were at combating stress and emotional eating through surveys. 87.5 percent of participants said that they were becoming more aware of their emotional triggers, but only 37.5 percent reported that their eating behaviours changed as a result. The volunteers were invited to suggest alternative interventions, with ideas such as distracting funny content, meditation, brain teasers, and calling a friend emerging.

The third part dealt involved the development of a bra-mounted wearable sensor system that gathered EKG and EDA data in order to monitor the emotional state of the wearer. The EKG sensor pads were designed to fit snugly against the ribs, while the EDA sensor was designed to sit inside the bra cap to essentially measure boob sweat.

Four women tested the bra system while also using EmoTree app so that researchers could cross-reference the data. They wore the sensing system and reported their emotions for between four and six hours each day. "It was very tedious for participants to wear our prototyped sensing system as the boards had to be recharged every three to four hours, which resulted in participants having to finagle with their wardrobe throughout the day," explain the authors.

The system was successful in measuring arousal (how alert or bored person is) and valence (how positive or negative emotions are) in between 73 and 75 percent of the time.

"Based on these results, we conclude that building a wearable, physiological system is feasible," say the authors. "However, we will continue to explore how to build a robust, real-world system that stands up to every day challenges with regards to battery life, comfort, and being suitable for both men and women."

The next stage of research will involve taking real-time sensor data instead of log files and trying to predict emotions and show an appropriately timed, personalized intervention.

Since conducting this research, the team has moved to testing the use of Affectiva Q3 bracelets, which detect mood, so that both men and women can participate. The pilots, say the authors, have been "quite promising" for both sexes.

This story originally appeared on Wired UK.