BQ 2: Does human nature change over time?

The big questions of history

Does human nature change over time?

Preliminary question: Is there such a thing as human nature? I have a personal nature: traits and dispositions that characterize me. You have a personal nature. Do our individual natures overlap?

The answer is certainly yes. If I smash my thumb with a hammer, it hurts. If I smash your thumb with a hammer, it hurts. I can tell by your howl. If my kid has a good day at school, I’m happy. Same for you if your kid has a good day.

Of course you and I aren’t identical. I like vanilla ice cream. You prefer chocolate. So even within a broad human nature, there's room for individuality. This is why there are limits to the golden rule, a version of which is found in just about every religion. The rule is premised on a shared human nature. Yet if I do unto you as I would have you do unto me, you’ll get vanilla ice cream.

The idea of a shared human nature is what makes much storytelling possible. Novelists, playwrights and screenwriters make up characters, and aspects of those characters resonate with readers and audiences.

The idea of human nature is what makes friendship possible. I tell you my secrets in the understanding that they have some meaning for you, and vice versa. I learn more about myself by learning about you.

Some of the variations in human nature are striking enough to warrant speaking of human natures plural. Hippocrates described four humors: blood, yellow bile, black bile and phlegm. He associated each with a particular personality type. Different peoples have characterized other peoples collectively. The English called the French sex-crazed onion eaters. The French dismissed the English as smug shopkeepers.

For historians the issue is complicated by the element of time. They need to know whether human nature, whatever it might be at any moment, changes with time’s passing. When John Adams addressed Abigail Smith in a 1762 letter as “Miss Adorable," did she read it as a young woman being wooed would read it today? Apparently Adams’s usage had the desired effect, for Abigail agreed to marry him.

The second son of Franklin and Eleanor Roosevelt was named Franklin Jr. He died in infancy. Five years later the parents named another son Franklin Jr. When I mention this to my students today, they think it strange, as disrespectful to the deceased child. But it seemed natural to Franklin and Eleanor in the 1910s.

Does a change in sensibility like this amount to a change in human nature? Probably not, if it’s the only change. But if it’s part of a complex of changes, say regarding attitudes between parents and children, then maybe it does.

To the degree that it does, it suggests there might always be a gulf between the past and the present. The American philosopher Thomas Nagel wrote an article in 1974 called “What Is It Like to Be a Bat?” He concluded that humans would never know, because they would never be bats. The natures of humans and bats were too different.

Can I ever know what it was like to be a Roman soldier? The soldier and I share a species. I know what it’s like to feel hunger, and I presume that when the soldier was hungry, he felt much the same way. But I have no experience marching off to subjugate peoples I’m convinced are my inferiors. I don't live at a time when the average life expectancy was thirty years. I can't even say whether the shorter expected life span made the Roman soldier more or less careless with his own life.

Any individual's nature is shaped by genes and by environment. The human genome changes slowly. Environment can change rapidly. One thing that distinguishes humans from other species is the degree to which human babies are born with their brains undeveloped. This must be so, otherwise newborns couldn't pass through the birth canals of their mothers. But it’s a feature of our species as much as it’s a bug. It allows the brains of infants and children to develop in response to their environments.

An obvious manifestation of this is that infants in different cultures grow up speaking different languages. Other manifestations are more subtle but might be more significant. Benjamin Franklin had sixteen siblings. Children in America today typically have no more than one or two. Franklin learned his social and political skills in the crowd at his family's dinner table. Comparatively speaking, kids today can imagine they are the center of the universe. These contrasting experiences, internalized early, can make for very different expectations of life.

So the answer to the general question whether human nature changes over time is: Somewhat, and depending on how you define human nature. It’s possible, and maybe helpful but maybe not, simply to define human nature as that which doesn’t change.

The more useful question—for the next generation of historians to answer, perhaps with the help of neuroscientists and other specialists—is: In what ways does human nature change?

For example, historians observe that nearly every human society has engaged in war. They might be tempted to say war is wired into human nature. But closer investigation would reveal that some societies have been less attached to war than others. The historians would note that efforts have been made to render war less destructive than in the past. Wholesale slaughter of defeated populations is currently frowned upon. Enslavement of prisoners has essentially disappeared. Has human nature changed? Or are we merely better at reining it in? The answer could make a difference for public policy.

The twentieth century invented human rights as an operative concept. Anyone alive five hundred years earlier would have considered the idea fatuous. Is it, and are we just fooling ourselves? Or are we more generous toward our fellow humans than our ancestors were?

Again an obvious answer: A bit of each.

Future historians: Please get more specific.