Mass media messages form the backbone of public health campaigns. Through web and social media, television, radio, magazines, and posters, they can communicate health messages to large numbers of people at low cost. But how these media campaigns effectively increase our awareness of a given health risk or change our behavior for the better, is not always clear.
Surprisingly, the field of social neuroscience is providing power to predicting their success. A growing body of neuroimaging research over the last 15 years has confirmed a remarkable fact: human brains become aligned when we hear or see the same thing. Whether it’s an audience watching a movie, children in a classroom, or people talking to one another, brains have been shown to display similar neural activity or “synchronization” in people who are engaged with the same stimulus.
A team of social neuroscientists in the Department of Psychology are building on this finding to explore the neural underpinnings of group processes—from audience engagement with health messages to the emergence of complex group behaviors. “Comparing the brain responses of people when they are watching the same thing enables us to get a measure of how similarly they see the world,” says Martin Imhof, a Ph.D. student in the laboratory of Professor Harald Schupp, Professor of General and Biological Psychology at the University of Konstanz.
Imhof is behind a new study in NeuroImage that has applied the science of brain synchronization to predicting the success of alcohol risk campaigns. Young adults—a high-risk group for binge drinking—were hooked up to an electroencephalogram (EEG) while watching real-life health advertisements about risky alcohol use. While all health messages are meant to be effective, in reality some are better than others. The Konstanz research team, which besides social neuroscience researchers Imhof and Schupp also included health psychologist Professor Britta Renner, found out that the stronger, more engaging ads lead to more synchronized brain activity in viewers.
But the study went deeper, exploring exactly what happens to our brains when we watch strong versus weak anti-alcohol messages. The researchers found that responses in brain regions associated with higher-order processes, like attention, emotion, and personal relevance seemed to be more highly synchronized across audience brains while watching effective alcohol risk videos. “This shows that we picked up a meaningful signal that goes beyond just seeing and hearing, but demonstrates real audience engagement with messages contained in the video,” says Imhof, who is lead author on the study.
But will a group’s response to persuasive messages at the neural level also forecast responses at the behavioural level? In other words, will an engaging alcohol message lead to lower levels of drinking? To answer that question, Imhof bolstered the EEG measurements with surveys to monitor subsequent drinking behaviour change. He found that the similarity in brain activity during the strong, more engaging videos was associated with subsequent reductions in risky drinking. By showing that neural measures can help to predict health message success, the study shows promise for real-world settings.
“EEG enables us to look in detail at how brain coupling changes over time across the audience, which means we can identify key scenes in a video that lead to peaks in coupling,” says Imhof. As the study shows, these peaks in brain coupling could signal more audience engagement.
Brains in synch
Imhof’s study is based on a discovery made 15 years ago by a scientist named Uri Hasson from the University of Princeton. Hasson wanted to understand what makes movies engaging, so he examined the neural activity of people watching a classic Hollywood blockbuster “The good, the bad and the ugly.” Here he discovered the phenomenon of brain synchronisation—the way in which brains show similar neural activity when exposed to the same media—which he called inter-subject correlation.
Hasson’s study broke ground for a number of reasons, but principally because he studied neural activity of people in so-called “naturalistic” conditions. Neuroimaging studies usually presented subjects stimuli that were discrete, repetitive and bearing little resemblance to our normal experience of the world. Instead, Hasson created a paradigm for showing a longer, dynamic stimulus, opening the door to studying brains operating under more natural and social environments in which humans have evolved.
This marked the beginning of a flowering of research on inter-subject correlation, which included work by the group of Professor Schupp at the University of Konstanz. Ralf Schmälzle, who was then a Postdoc in the Schupp Lab of General and Biological Psychology, teamed up with the Renner Lab of Health Psychology to apply this to his work in understanding the dynamics of risk perception in the field of health psychology.
Health media campaigns, which are key instruments in public health, represented the perfect “naturalistic” stimuli that could be studied with inter-subject correlation.
“You can’t study these videos as discrete stimuli, you have to study them as they are used by the public,” says Schupp, who is a principal investigator in the research group “RiskDynamics” (FOR 2374), which is funded by the German Research Foundation (DFG), and in the Cluster of Excellence “Centre for the Advanced Study of Collective Behaviour” (EXC 2117) at the University of Konstanz.
Matt Birnholz, MDPeer