Mind Your Body: Inward Bound
The mysterious connection between emotion and physical sensation is coming into ever-sharper focus.
By March 9, 2015 - last reviewed on June 9, 2016published
The sight of a blazing sunset, the sound of a ringing phone, the aroma of fresh bread as you pass a bakery—we tend to think of sensory perception as the way we process external stimuli with our eyes, ears, mouth, nose, and skin. Yet there’s another form of sensory perception, known as interoception, that involves the feelings that originate within the body, such as hunger, thirst, breathlessness, pain, temperature, heartbeat, muscle tension, and bladder pressure. Aside from the obvious necessity—you won’t live long if you don’t know that you’re starving—a recent explosion of interest in the phenomenon has illuminated its role beyond ensuring our physical survival. As a growing body of research reveals, interoception is intimately linked with how we process emotion. And if people can alter their sense of their body’s physiological condition, some suggest, it can potentially shift their emotional state.
Interoception is a matter of degrees, says Vivien Ainley, a neuropsychologist at the University of London who studies how interoceptive signals affect emotion, cognition, and other facets of how we conceive of the self. While everyone is aware of internal sensation to some extent, there’s wide variability in how sensitive we are to this input, as evidenced in studies that measure the accuracy with which people recognize their own heartbeat. Those with high interoceptive awareness—that is, people who are more accurate on heartbeat-measurement tasks—have been shown, Ainley says, “to be more intuitive, experience stronger emotional arousal, have better memory for emotional material, and perhaps be better able to control their negative emotions.”
When we can’t accurately gauge our body’s signals, there may be a price to pay. Low interoceptive awareness has been associated with clinical problems, including depersonalization disorder, eating disorders, and the experience of unexplained physical symptoms, such as pain. Studies have also linked low interoceptive awareness with depression. In a paper published last year in Biological Psychiatry, people with severe untreated depression who were asked to perform an interoceptive attention task showed lower brain activation than nondepressed people; the researchers concluded that major depressive disorder is associated with abnormal interoception. In a similar study, Daniella Furman, a doctoral candidate in psychology at Stanford University, together with colleagues, found that people with depression are less attuned to their own heartbeat. The worse their interoceptive awareness, she says, “the less intense were their experiences of positive emotion in daily life, and the more likely they were to have difficulty with everyday decision making.”
The idea that our emotions correlate with physical sensations has been around, of course, since the birth of psychology. What’s become clear only in recent years is how closely they’re connected as neural processes. In a study published in NeuroImage in 2012, subjects who monitored their heartbeat and watched videos of people telling emotional stories showed, during each activity, similar patterns of activation in the insular cortex—the region deep inside the brain responsible for both emotional feelings and interoception. Their findings, the researchers wrote, lend support to the idea that bodily awareness and emotion are “intimately linked.” In another study, published in Human Brain Mapping in 2013, the evaluation of emotional and bodily states was found to spark similar patterns of activation in the insular cortex, offering further proof “that attending to the bodily state underlies awareness of one’s emotional state.”
While the correlation between interoceptive awareness and emotion has become increasingly well established, researchers are now looking at exactly how the former influences the latter, or vice versa—and what that might mean for techniques to optimize mental wellbeing in the future.
“It’s too early to say that by making people more sensitive to their bodily state, we’ll be able to cure different problems,” says Anil Seth, a cognitive neuroscientist and the codirector of the Sackler Centre for Consciousness Science at the University of Sussex whose research examines how the brain processes sensory input. “But we can shape many things that are otherwise relatively stable when we give people the right feedback and training. My impression is that interoceptive ability is very likely something that one can change, and that will have interesting consequences, potentially opening new routes to treatment.”