Since the 19th century, neuroscientists have speculated that human emotion might be a kind of secondary sensory response: The brain translates sense data (the sight of an oncoming bus) into a physical reaction (elevated heart rate), which then triggers an emotional one (fear that bus is going to hit). Testing the theory directly is not ethically possible, but new, indirect experiments support the link between sensation and emotion.
Hugo Critchley of University College London looked for signs that emotional awareness is tied to heartbeat perception in the brain. If physical reactions trigger emotion, he reasoned, people who are highly attuned to bodily processes should also be unusually sensitive. He and his collaborators tested the ability of 17 subjects to perceive whether a series of tones was synchronized with their hearts. The researches also scanned the subjects’ brain activity and later asked them to fill out a questionnaire. Subjects who more accurately judged their heartbeats tended to have greater activity in the right anterior insula, a region deep in the brain. They also reported feeling negative emotions, such as fear or anger, more deeply than the other subjects did.
Stefan Wiens of Karolinska Institute in Stockholm, who helped run the study, notes that people who think they are viscerally aware often aren’t, and that those who are often do not realize it. So far, trying to teach people to recognize the timing of their heartbeats has not exactly lead to greater sensitivity. Attempts to learn, Wiens says, have tended to frustrate subjects or make them more anxious.
