In comparison to when people talk to close friends or partners they talk differently than when they address a physician or a stranger. But these differences in speech are quite subtle and hard to pinpoint, say researchers.
Johanna Derix, Tonio Ball and their colleagues from the Bernstein Centre and the University Medical Centre in Freiburg, Germany, report that they were able to tell from brain signals who a person was talking to.
This discovery could contribute to the further development of speech synthesisers for patients with severe paralysis, the journal Frontiers in Human Neuroscience reports.
As against the experimental research common in human neuroscience, scientists studied natural and non-experimental behaviour.
Patients who, for medical reasons, had electrodes implanted underneath their skull allowed their brain activity to be recorded during daily life in the hospital, according to a statement of the University Medical Centre.
Freiburg researchers compared data recorded during natural conversations that the patients had with their physicians and their life partners.
They found pronounced differences in the anterior temporal lobe, a brain area well known for its significance in social interaction. Several components of neural signals that are detectable on the brain surface can convey such information.
"This study is only the first step towards elucidating the neural basis of human everyday behaviour," neuroscientist and physician Tonio Ball said.
"Such investigations will become especially important in developing new neurotechnological treatment options for patients with impaired motor and language functions that work in real life situations," he said.