Scientists in Germany recently used mobile electroencephalography (EEG) headsets to record the brain activity of romantic partners in their everyday environment. Their findings, which appear in Scientific Reports, provide more evidence that positive emotional experiences are associated with greater activity in the frontal areas of the left half of the brain.
“The question how emotions are processed in the brain is one of the most well-researched topics in neuroscience. Many studies have illustrated that emotional processing is lateralized in the brain, meaning that one hemisphere is dominant in the processing of emotions,” said study author Julian Packheiser, a postdoctoral researcher in the Biopsychology Lab at the Ruhr University Bochum.
“The precise nature of this lateralization is however unclear to this day, likely due to the lack of ecological validity in experiments investigating emotions. To investigate the neural basis of emotions, we have to make use of technologies such as EEGs or MRIs to gather data from the brain directly, but this setup does not permit us to actually behave in accordance to the felt emotions as they are heavily physically restraining.”
“Our study wanted to alleviate this lack of ecological validity as we brought the experiment to the participants’ natural environment and they could move freely using a so-called mobile EEG,” Packheiser told PsyPost.
The researchers used a mobile EEG system that recorded the brain activity of 16 couples in their own homes during embracing, kissing and emotional speech. The EEG system also included acceleration sensors that were used to record movement patterns as well, which allowed the researchers to control for movement-based artifacts in the data.
Packheiser and his colleagues were particularly interested in EEG data in the alpha frequency band between 8 and 13 Hz and the beta frequency band between 13 and 30 Hz.
“We focused on differences in asymmetrical processing in the alpha frequency band due to the pronounced role of frontal alpha asymmetries in emotional processing. Since beta power asymmetries have been demonstrated to be highly comparable in function to alpha power asymmetries in studies investigating motor preferences and resting state oscillations, we also included beta power asymmetries as a dependent variable in our study,” the researchers explained.
Confirming previous findings, the researchers found evidence for emotional lateralization.
“Our results were in agreement with previous EEG literature suggesting that emotions are processed in the brain depending on the valence of the emotion. Positive emotions like love and happiness are more strongly processed in the left brain hemisphere whereas negative emotions are dominantly processed in the right hemisphere,” Packheiser explained.
“Since we could replicate these previous findings, it illustrates that laboratory experiments can generalize to real-life conditions which is an important implication for experimental psychology and neuroscience. Our lab work can therefore be transferred to the real world.”
But the use of EEG technology comes with some limitations.
“A major caveat is that EEG only allows for the measurement of brain activity located closely to the skull, since the electrodes measure activity on the brain surface. However, many emotional processes also take place in phylogenetically older brain structures that are located more deeply in the brain,” Packheiser said.
“With EEG, we have no access to them. Future research could use mobile magnetoencephalography (MEG) to also measure deep brain activity with less physical constraints to the participants in order to complete the picture. Furthermore, our couples were exclusively from Western societies. Cross-cultural experiments are also needed since social touch is experienced and executed differently across cultures.”
The study, “Investigating real-life emotions in romantic couples: a mobile EEG study“, was authored by Julian Packheiser, Gesa Berretz, Noemi Rook, Celine Bahr, Lynn Schockenhoff, Onur Güntürkün, and Sebastian Ocklenburg.