Broken hearts and broken bones: What’s the connection?

'Hurt feelings' or 'broken hearts' reflect painful experiences. Isn't it striking, however, that the language we use to describe emotional pain is, in fact, the language we use to describe physical pain as well? Broken heart and broken bones, for instance.

In 15 different languages, the words used to describe emotional pain are almost exclusively borrowed from the physical pain domain. But is feeling hurt or unloved truly comparable to feeling physical pain or is this merely poetic license or coincidence? Mounting evidence suggests that the connection is much deeper.

Defining pain

Before continuing to explore this connection, it is important to clearly define the different pains we will be referring to here to avoid any misinterpretation. What we refer to as emotional pain here, is referred to as social pain by cognitive social psychologists.

Social pain is defined as the distressing experience arising from the perception of actual or potential psychological distance from close ones or a social group. Put simply, it is the pain experienced when you feel rejected, treated unfairly or when any relationship in your life is threatened, damaged or lost.

Medically, physical pain is ‘unpleasant sensory and emotional experience associated with actual or potential tissue damage’, meaning the pain experienced upon bodily injury. Studies by the University of California, Los Angeles prove that both these type of pains share neural and computational mechanisms.

Anatomy of pain

The brain’s physical pain system consists of three regions in the cortex: the somatosensory cortex, the insula and the dorsal anterior cingulated cortex [or dACC].

The somatosensory cortex helps us pinpoint the location of pain in the body, particularly pain on the outer surface of the body. For instance, it helps differentiate the pain applied to the left or the right hand.

The insula responds to painful stimulation, particularly internal or visceral forms of pain, and seems to provide the brain with a representation of the body’s overall state.

The dACC is associated with the distress of physical pain—it determines how much a particular pain stimulation bothers an individual.

Pain researchers have subdivided pain experience into two psychological components: sensory processing and felt unpleasantness. According to neuroimaging studies, the dACC plays a role in the ‘felt unpleasantness’ of physical pain; whereas the somatosensory cortex and posterior insula are associated with the sensory-discriminative aspects of pain.

Specifically, increasing levels of dACC activity correspond with increasing levels of self-reported pain unpleasantness. Thus, individuals who are pain-sensitive by nature show more dACC activity and report greater levels of perceived unpleasantness to painful stimulation.

For decades, neurosurgeons have performed cingulotomies [a form of psychosurgery], a circumscribed lesioning of the dACC, to treat intractable [Ed: difficult to treat or manage] chronic pain. People who have undergone cingulotomies for chronic pain report that they are still able to feel the pain but that it no longer bothers them. This underlines the dACC’s role in the distressing, rather than the sensory, component of physical pain.

The dACC-social pain connection

In addition to the part it plays in processing of physical pain, animal research shows that dACC is also relevant in our experience of social pain. One primate study found that when the dACC was electrically stimulated in monkeys, they produced the same distress vocalisations that they produced when they felt estranged from a caregiver. In another study, when the dACC in monkeys was surgically altered, their distress vocalisation significantly reduced even when they were separated from their mothers.

Several lines of evidence suggest that dACC [specifically areas 240 and 320] is involved in our experience [distress] of both physical and social pain.

Excerpted from The pains and pleasures of social life: A social cognitive neuroscience approach and Why rejection hurts: a common neural alarm system for physical and social pain by Matthew D. Lieberman and Naomi I. Eisenberger, Department of Psychology, University of California, Los Angeles [UCLA], California.Matthew D Lieberman is Professor of Psychology, Psychiatry and Biobehavioral Sciences, Franz Hall, UCLA, California. Naomi Eisenberger is assistant professor in the Department of Psychology at UCLA.