We like to think that all people feel empathy to the same degree. In reality, it varies a lot from one person to the next, like most mental traits. We are half-aware of this when we distinguish between “normal people” and “psychopaths,” the latter having an abnormally low capacity for empathy. The distinction is arbitrary, like the one between “tall” and “short.” As with stature, empathy varies continuously among the individuals of a population, with psychopaths being the ones we find beyond an arbitrary cut-off point and who probably have many other things wrong with them. By focusing on the normal/abnormal dichotomy, we lose sight of the variation that occurs among so-called normal individuals. We probably meet people every day who have a low capacity for empathy and who nonetheless look and act normal. Because they seem normal, we assume they are as empathetic as we are. They aren’t.

Like most mental traits, empathy is heritable, its heritability being estimated at 68% (Chakrabarti and Baron-Cohen, 2013). It has two distinct components: cognitive empathy and affective empathy. Some researchers identify a third component, pro-social behavior, but its relationship to the other two seems tangential.

Cognitive empathy appears to be the evolutionarily older component of the two. It is the capacity to understand how another person is feeling and then predict how different actions will affect that person’s emotional state. But this capacity can be used for selfish purposes. Examples are legion: the con artist; many telemarketers; the rapist who knows how to charm his victims …

Affective empathy is the younger component, having developed out of cognitive empathy. It is the capacity not just to understand another person’s emotional state but also to identify with it. A person with high affective empathy will try to help someone in distress not because such help is personally advantageous or legally required, but because he or she is actually feeling the same distress.

Affective empathy may have initially evolved as a means to facilitate relations between a mother and her children. Later, and to varying degrees, it became extended to other human relationships. This evolutionary trajectory is perceptible in young children:

Children do not display empathic concern toward all people equally. Instead, they show bias toward individuals and members of groups with which they identify. For instance, young children of 2 years of age display more concern-related behaviors toward their mother than toward unfamiliar people. Moreover, children (aged 3-9 years) view social categories as marking patterns of interpersonal obligations. They view people as responsible only to their own group members, and consider within-group harm as wrong regardless of explicit rules, but they view the wrongness of between-group harm as contingent on the presence of such rules.(Decety and Cowell, 2014)

Similarly, MRI studies show that adults are much more likely to experience emotional distress when they see loved ones in pain than when they see strangers in pain. A stranger in distress will evoke a response only to the degree that the observer has a high capacity for affective empathy. The higher the capacity the more it will encompass not only loved ones but also less related individuals, including total strangers and nonhumans:

Humans can feel empathic concern for a wide range of ‘others’, including for nonhuman animals, such as pets (in the Western culture) or tamagotchi (in Japan). This is especially the case when signs of vulnerability and need are noticeable. In support of this, neural regions involved in perceiving the distress of other humans, such as the anterior cingulate cortex and insula, are similarly activated when witnessing the distress of domesticated animals(Decety and Cowell, 2014)

While we associate affective empathy with morality, the two are not the same, and there are situations where the two come into conflict. In most societies, kinship is the main organizing principle of social relations, and morality affirms this principle by spelling out the duties to one’s parents, one’s kin, and one’s ethny. The importance of kinship may be seen in the Ten Commandments, which we wrongfully assume to be universal in application. We are told we must not kill, steal, lie, or commit adultery if the victims are “thy neighbor,” which is explained as meaning “the children of thy people” (Leviticus 19:18). High-empathy individuals may thus subvert morality if they view all human distress as being equal in value. At best, they will neglect loved ones in order to help an indefinitely large number of needy strangers. At worst, strangers may develop strategies to exploit high-empathy individuals, i.e., to milk them for all they are worth.

Mapping empathy in the human brain

Empathy appears to arise from specific mechanisms in the brain, and not from a more general property, like general intelligence. It is produced by a sequence of mental events, beginning with “mirror neurons” that fire in tandem with the observed behavior of another person, thereby generating a mental model of this behavior. Copies of the model are sent elsewhere in the brain to decode the nature and purpose of the behavior and to predict the sensory consequences for the observed person. Affective empathy goes further by feeding these predicted consequences into the observer’s emotional state (Carr et al., 2003).

Recent MRI research has confirmed that empathy is associated with increased development of certain regions within the brain. Individuals who score high on cognitive empathy have denser gray matter in the midcingulate cortex and the adjacent dorsomedial prefontal cortex, whereas individuals who score high on affective empathy have denser gray matter in the insula cortex (Eres et al.,2015). A high capacity for affective empathy is also associated with a larger amygdala, which seems to control the way we respond to facial expressions of fear and other signs of emotional distress (Marsh et al., 2014).

Can these brain regions be used to measure our capacity for affective empathy? Two studies, one American and one English, have found that “conservatives” tend to have a larger right amygdala (Kanai et al.,2011; Schreiber et al., 2013). This has been spun, perhaps predictably, as proof that the political right is fear-driven (Hibbing et al., 2014). A likelier explanation is that “conservatives” are disproportionately drawn from populations that have, on average, a higher capacity for affective empathy.

Do human populations vary in their capacity for affective empathy?

Is it possible, then, that this capacity varies among human populations, just as it varies among individuals? I have argued that affective empathy is more adaptive in larger, more complex societies where kinship obligations can no longer restrain behavior that seriously interferes with the ability of individuals to live together peacefully and constructively (Frost, 2015). Whereas affective empathy was originally expressed mainly between a mother and her children, it has become progressively extended in some populations to a wider range of interactions. This evolutionary change may be compared to the capacity to digest milk sugar: initially, this capacity was limited to early childhood, but in dairy cattle cultures it has become extended into adulthood.

I have also argued that this evolutionary change has gone the farthest in Europeans north and west of the Hajnal Line (Frost, 2014a). In these populations, kinship has been a weaker force in organizing social relations, at least since the early Middle Ages and perhaps since prehistoric times. There has thus been selection for mechanisms, like affective empathy, that can regulate social interaction between unrelated individuals. This selection may have intensified during two time periods:

– An initial period corresponding to the emergence of complex hunter/fisher/gatherers during the Mesolithic along the shores of the North Sea and the Baltic. Unlike other hunter-gatherers, who were typically small bands of individuals, these people were able to form large coastal communities by exploiting abundant marine resources. Such communities were beset, however, by the problem of enforcing rule compliance on unrelated people, the result being strong selection for rule-compliant individuals who share certain predispositions, namely affective empathy, proneness to guilt, and willingness to obey moral rules and to expel anyone who does not (Frost, 2013a; Frost, 2013b).

– A second period corresponding to the spread of Christianity among Northwest Europeans, particularly with the outbreeding, population growth, and increase in manorialism that followed the Dark Ages (hbd chick, 2014). The result was a “fruitful encounter” between the two: on the one hand, Christianity, with its emphasis on internalized morality, struck a responsive chord in these populations; on the other hand, the latter modified Christianity, increasing its emphasis on faith, compassion, and original sin (Frost, 2014b).

Conclusion

Recent research has brought much insight into the nature of empathy, which should no longer be viewed as being simply a noble precept. We now understand it as the outcome of a sequence of events in specific regions of the brain. We have also learned that individuals vary in their capacity for empathy and that most of this variability is heritable, as is the case with most mental traits. Moreover, empathy has two components—cognitive and affective—and the strength of one in relation to the other likewise varies. Although we often consider affective empathy to be desirable, it can have perverse and even pathological effects in some contexts.