KeywordsSocial Exclusion Attachment Style Anterior Insula Physical Pain Affective Component
The unpleasant experience that is associated with actual or potential damage to one’s sense of social connection or social value (Eisenberger 2012)
When individuals are asked to identify their most painful experience, they often pick negative social experiences, such as the loss of a loved one or a painful relationship breakup, rather than physically painful experiences. In fact, individuals tend to label such negative social experiences as “painful” or “hurtful,” drawing a linguistic parallel between physical pain and social pain, the painful feelings that follow from rejection or loss. Indeed, due to the importance of social connection for human survival, it has been hypothesized that, over the course of evolutionary history, the physical pain system, which alerts us to threats to physical safety, may have been co-opted to monitor for threats to social safety. Specifically, given the immaturity of most mammalian infants at birth, connection to a caregiver is essential for critical survival needs, such as obtaining nourishment and securing protection. Thus, to the extent that being separated from a caregiver is a major threat to survival, feeling “hurt” by this separation may be an adaptive way to prevent social separation. Consistent with this idea, research over the past decade has suggested that physical and social pain may rely on shared neural substrates. A neural overlap between physical and social threats offers an explanation for why negative social experiences are reported as being so distressing, as well as why this increased sensitivity to social threats may be adaptive and necessary.
Evidence for a Physical-Social Pain Overlap
To the extent that social pain processes co-opted aspects of the physical pain system, experiences of social pain should rely on neural regions associated with pain processing. Along these lines, the neural circuitry underlying physical pain is typically decomposed into two components: the sensory component and the affective component (reviewed in Treede et al. 1999). The sensory component processes information about the physical aspects of pain stimuli, such as the quality, the location, and the intensity of the stimuli. This information is primarily processed within the primary and second somatosensory cortex as well as the posterior insula. In contrast, the affective component of physical pain refers to the unpleasantness or emotional distress associated with the painful stimuli as well as the motivation to terminate the stimuli causing the distress. The affective component has been more strongly associated with activation in the dorsal anterior cingulate cortex (dACC) and the anterior insula (AI). Experientially, affective and sensory processes occur simultaneously in the presence of physical pain; however, evidence suggests these two processing streams are indeed distinct. Hence, chronic pain patients who have undergone a surgical procedure that lesions the dACC (cingulotomy) show intact processing of sensory information (e.g., they recognize the physical sensation) but exhibit impaired affective processing (e.g., it no longer bothers them) (Foltz and White 1962). Social pain is often accompanied by distress in the absence of any physical stimulus. Thus, the affective component of the pain system is likely most involved in terms of social pain processing.
In line with this, activation in the areas associated with the affective component of pain (dACC and AI) tends to occur during episodes of social rejection (Eisenberger et al. 2003), negative social evaluation (Eisenberger et al. 2011), and even while remembering a deceased loved one (Gündel et al. 2003). Additionally, increased neural activity in these regions is also associated with increased self-reported feelings of social distress during such events (Eisenberger et al. 2003). Finally, specific traits associated with increased sensitivity to social rejection (e.g., low self-esteem, anxious attachment style, interpersonal sensitivity) are associated with increased activity in the dACC and AI in response to social exclusion, whereas traits associated with reduced sensitivity to rejection (e.g., avoidant attachment style, greater perceived social support) are associated with reduced activity in the dACC and AI in response to social exclusion (see Eisenberger 2012 for review). This evidence suggests that both the physical pain and social pain alarm systems may overlap, relying on shared neural circuitry.
Two implications stem from the probable integration of social pain into the physical pain alarm system: (1) sensitivities to one type of pain should extend to the other type of pain, and (2) factors known to enhance or reduce one type of pain should influence the other type in similar ways. In line with the former, individuals who are dispositionally sensitive to one type of pain are also more sensitive to the other type as well. For instance, healthy individuals who report higher levels of pain in response to experimental physical pain manipulations (e.g., painful heat stimuli) also report more social pain in response to experimental social exclusion (Eisenberger et al. 2006). Additionally, those high in rejection sensitivity or those who have insecure attachment styles (features likely to be associated with sensitivity to social pain) report more physical pain symptoms (Waldinger et al. 2006). Such research supports the idea that individuals tend to exhibit shared sensitivities to social and physical pain, presumably due, in part, to their shared neural circuitry.
Research has also supported the second implication that factors that influence one type of pain should similarly influence the other type of pain. For instance, factors that typically reduce social pain, like social support, can also reduce self-reported physical pain (Master et al. 2009). Likewise, drugs that reduce physical pain, such as acetaminophen (Tylenol), have also been shown to reduce daily reports of social pain as well as pain-related neural activity to social exclusion (DeWall et al. 2010). Together, this evidence supports the hypothesis that physical and social pain rely on shared neural circuitry.
The observed neural overlap between physical and social pain makes it clear why threats to social ties are often described as being “painful” or “hurtful.” Moreover, this physical-social pain overlap may also help to understand why emotional traumatic experiences in early life are often associated with downstream health consequences (e.g., chronic pain, depression), as well as later interpersonal difficulties. Recognition of these consequences can encourage acknowledgment of negative social experiences as truly painful and as such should not be dismissed. While most findings in this area emphasize the role of the affective component of pain in the neural processing of social experience, there is debate about whether and how the sensory component may also overlap. Some studies have shown activation in the somatosensory cortex during recollections of socially painful experiences (e.g., romantic breakup) (see Eisenberger 2012 for review). Future work will be needed to determine whether physical and social pain overlap in both the sensory and affective components of pain.