Researchers used biometric sensors to monitor the participants’ brain activity, gauge their emotions and reactions, evaluate attention, and measure their skin response to stimuli as they were asked to read six articles on different topics. The small test involved 60 participants from the U.S., U.K. and Japan.

Each article had three ads that had relevance to the article ranging from high to low. An article about soccer had ads for soccer apparel, beverages and electronics, for example. The placement of the most relevant ad varied across the articles. The researchers then conducted in-person interviews with the participants.