Psychologists have long noted the importance of social connection for human survival and have suggested that humans have a fundamental “need to belong” or to be socially connected to others [1
]. Recent models have attempted to advance this idea further by proposing that, like other basic needs, a lack of social connection may feel “painful.” Specifically, we and others have argued that there may be an overlap in the neural circuitry underlying experiences of physical pain and “social pain”—the painful feelings following social rejection or social loss [4
From an evolutionary perspective, the idea that a lack of social connection feels “painful” makes good sense. As a mammalian species, humans are born relatively immature, without the capacity to feed or fend for themselves and instead rely almost completely on a caregiver to provide care and nourishment. Because of this prolonged period of mammalian immaturity, the social attachment system—which promotes social bonding—may have piggybacked onto the physical pain system, borrowing the pain signal itself to indicate when social relationships are threatened, thus promoting survival [8
]. In other words, to the extent that being separated from a caregiver is such a severe threat to survival, being “hurt” by experiences of social separation may be an adaptive way to prevent them.
Indeed, our language provides nice anecdotal evidence for the hypothesis that social and physical pain rely on shared neural circuitry. Specifically, when we describe experiences of social pain—social rejection or social loss—we often do so with physical pain words, complaining of “hurt feelings” or “broken hearts.” In fact, this pattern has been shown to exist across many different languages and is not unique to the English language [8
]. Moreover, at least in the English language, we have no other means of expressing these “hurt feelings” other than through the use of physical pain words. Still, linguistic evidence alone does not substantiate the claim that physical and social pain processes overlap. One way to more convincingly demonstrate an overlap in the mechanisms that support physical and social pain processes is to show that they rely on shared neural substrates.
Over the past several years, we have directly investigated the hypothesis that physical and social pain processes overlap using a variety of different methodologies, including behavioral, genetic, and neuroimaging approaches. As a first test of this hypothesis, we have investigated whether experiences of social pain activate neural regions that are typically implicated in physical pain processing. As a second test, we have investigated whether there is evidence for some of the expected consequences of such an overlap. For example, we have explored whether individuals who are more sensitive to one kind of pain are also more sensitive to the other, as individual differences in the functioning of this shared, underlying circuitry should be manifested in both kinds of pain. We have also explored whether altering (increasing or decreasing) one type of painful experience alters the other in a similar manner. Here, I review the evidence accumulated through these investigations (see for a conceptual model). Together, these data support the idea that experiences of social rejection, exclusion, or loss may be described as ‘painful’ because they rely, in part, on pain-related neural circuitry.
Figure 1 A conceptual model depicting the overlapping neural regions activated by physical and social pain as well as the consequences of this overlap for trait differences in sensitivity to pain (individual differences in physical pain sensitivity should correlate (more ...)