Dark portents of civil war were looming as the American poet Walt Whitman celebrated the transformative song of empathy. “I do not ask the wounded person how he feels,” he wrote in his 1855 book Leaves of Grass, “I myself become the wounded person.” The ensuing battle over slavery, an institution that Charles Darwin called “the greatest curse on Earth,” would seem an unlikely place to find hope in human potential. And yet, as Whitman wrote during his volunteer service with wounded Union soldiers, “I'll pour the verse with streams of blood, full of volition, full of joy.”

Darwin’s On the Origin of Species was published in the United States one year prior to the first fateful shots at Fort Sumter that began the bloodiest conflict on American soil. With few exceptions, naturalists in the United States greeted the theory of natural selection the same way that celebrated paleontologist Louis Agassiz did, as “a scientific mistake, untrue in its facts, unscientific in its method, and mischievous in its tendency.” What was worse, critics claimed that Darwin’s theory divided moral sentiments from divinity and pitted science against humanity. And yet, for Walt Whitman, the advent of Darwinism meant that “the world of erudition, both moral and physical, cannot but be eventually better’d and broaden’d in its speculations.” Whitman’s vision of empathy was one that embraced a Darwinian nature.

However, modern scholars in science studies view the concept of empathy in disarray. They cite how its recent coinage in the early 20th century from the German term Einfühlung (“feeling into”) and the varied and subjective interpretations with which it was initially used in psychoanalytic theory “offer no one definitive account of empathy, nor a reduction of one kind of empathy experience into another,” summarizes Susan Lanzoni in the introductory essay to a special issue of Science in Context devoted to the topic. However, following Whitman, I would argue that a Darwinian understanding of empathy has been entirely consistent and built from Darwin’s initial hypothesis to establish an empirical framework by the mid-1960s. Ironically, given the initial reception Darwin received in America, the primary work in this area was conducted by scientists in the United States itself.

It may initially seem to be a problem that Darwin used the earlier term sympathy to describe the evolutionary foundations of moral behavior. However, there can be little doubt as to what he meant. Citing Adam Smith’s Theory of Moral Sentiments, Darwin wrote in The Descent of Man:

[T]he basis of sympathy lies in our strong retentiveness of former states of pain or pleasure. Hence, "the sight of another person enduring hunger, cold, fatigue, revives in us some recollection of these states, which are painful even in idea." We are thus impelled to relieve the sufferings of another, in order that our own painful feelings may be at the same time relieved.

Darwin continued in Expression of the Emotions in Man and Animals by stating that, “from the power of the imagination and of sympathy we put ourselves in the position of the sufferer.” It is clear that in his use of the word sympathy he was referring to an individual “feeling into” the emotional state -- or taking the perspective of -- another individual as was meant by the German word Einfühlung. In fact, many of the early German theorists of Einfühlung cited Darwin in their own work on the subject, including Robert Vischer who is regarded as the philosopher who first developed the concept.

Darwin went on to propose two hypotheses to support this theory of empathic perspective-taking: 1) individuals would be expected to mimic the behaviors of another when observing them perform a difficult task and 2) they would be physically distressed when witnessing another individual's pain and would seek to stop it. It would take nearly a century for these hypotheses to be tested, but once they were it placed the scientific study of empathy on a new foundation.

While the psychoanalytic explorations of empathy took a variety of directions, laboratory experiments with primates offered the empirical grounding necessary for a precise definition. In 1917 the German psychologist Wolfgang Köhler, who repeatedly criticized the Einfühlung theory for its vagueness and lack of factual evidence, demonstrated motor mimicry in chimpanzees by having one individual climb on top of piled crates in order to reach a hanging banana as a second chimp observed from below. Köhler documented how the observer frequently stretched out their own arm as the climber reached for the prize, a clear example of mimicry suggesting that they were taking the perspective of the other as Darwin hypothesized.

But the coup de grâce arrived with a series of papers published in the United States between 1959 and 1963. Psychologist Robert E. Miller and colleagues at the University of Pittsburgh sought to test Darwin’s prediction that expressions of fear in animals had evolved as communicative signals for other members of their group. By first training a monkey to press a bar in order to prevent a mild electric shock, the researchers went on to demonstrate that the expression of fear by a second monkey that received a shock in an adjoining cage activated an identical reaction in the first, motivating them to press the bar even though they felt no shock themselves. This reaction was the same even when the expression was seen on a silent television monitor or in the form of a still photograph. As the researchers predicted, the monkeys’ “empathic relationship [was] dependent upon some nonverbal communication of affects.”

Finally, in 1964, psychiatrists Jules Masserman and Stanley Wechkin of the North Western University Medical School in Chicago employed a similar approach but added the additional element of an “altruistic” choice. After training monkeys to associate bar pressing with causing a shock to be administered in the adjoining cage, the researchers offered the first monkey a food reward if they would intentionally administer a shock to the second. Few accepted this devil’s bargain. The researchers discovered that the majority of monkeys, even those who were strangers to one another, “will consistently suffer hunger rather than secure food at the expense of electroshock to a conspecific.” When offered the opportunity to celebrate themselves, our primate cousins chose to sing a different tune.

But while the science of empathy revealed a path towards reconciliation between the empirical research of the mid-twentieth century with the predictions from the nineteenth, the wounds inflicted during the American Civil War -- or what some still call the "War of Northern Aggression" -- remain slow to heal. However, in the example of Walt Whitman, we find someone who rejected such binary opposites, whether between North versus South, science versus art, and even the love of man versus woman. He reminds us that to celebrate others is to celebrate ourselves, even during our darkest hour. In 1892, while bedridden from a paralytic stroke and barely able to hold a pen to paper, this great "poet of science" offered a final paean to his early inspiration in a work entitled Darwinism—(then Furthermore). "Meantime, the highest and subtlest and broadest truths of modern science wait for their true assignment and last vivid flashes of light—as Democracy waits for its."


Agassiz, J.L.R. 1860. "[Review of] On the Origin of Species." American Journal of Science and Arts (Ser. 2) 30 (July): 142-154.

Darwin, C.R. 1871. The Descent of Man, and Selection in Relation to Sex (London: John Murray).

Darwin, C.R. 1872. The Expression of the Emotions in Man and Animals (London: John Murray).

Kohler, W. 1917. Intelligenzprüfungen an Anthropoiden (Berlin: Royal Prussian Society of Sciences). Translated by Ella Winter in 1925 as The Mentality of Apes (New York: Harcourt).

Lanzoni, S. 2012. "Introduction: Emotion and the Sciences: Varieties of Empathy in Science, Art, and History," Science in Context 25(3): 287-300. doi:10.1017/S0269889712000105

Masserman, J.H., Wechkin, S., Terris, W. 1964. "'Altruistic'" behavior in rhesus monkeys," The American Journal of Psychiatry 121(6): 584-585. doi:10.1176/ajp.121.6.584

Miller, R.E., Murphy, J.V., Mirsky, I.A. 1959. "Relevance of Facial Expression and Posture as Cues in Communication of Affect Between Monkeys," AMA Arch Gen Psychiatry 1(5): 480-488. doi:10.1001/archpsyc.1959.03590050048006

Miller, R.E., Banks Jr., J.H., Ogawa, N. 1963. "Role of facial expression in 'cooperative-avoidance conditioning' in monkeys. Journal of Abnormal and Social Psychology 67(1): 24-30. doi:10.1037/h0044018

Whitman, W. 1855. Leaves of Grass (Brooklyn: New York).

Whitman, W. 1892. Complete Prose Works (Philadelphia: David McKay).