“Thou shalt not kill” may be the most recognizable moral prohibition in societies around the world.
But where does your sense of justice come from?
Throughout history, justice and laws about wrongdoing have been attributed to one god or another. More recently, justice has been traced to moral truths that can be discovered by judges and other legal experts, and to social norms that vary across cultures.
However, our research instead suggests that the human sense of justice, and criminal laws, is generated by the human brain.
Put simply: Being human makes you a decent lawmaker even if you’ve never stepped foot in law school. To an important extent, criminal laws appear to be the end products of gut feelings about justice that are a part of human nature.
Here’s how we investigated just how universal these intuitions are:
Testing the human brain’s sense of justice
Human conflict ranges from the mild, as when neighbors disagree about the appropriate loudness of music, to the serious, including cases of fraud, robbery, rape, homicide – the stuff of criminal law.
Laws and litigation come in handy when you’re butting heads with someone. But your brain automatically generates intuitions about justice when there is even the potential for conflict, long before you set foot in court. People, even young children, have strong feelings about what counts as a wrongful action and how much punishment a wrongdoer deserves.
These justice intuitions come naturally to everyone. They’re like human lungs or human retinas – part of being human.
So maybe the standard-issue human brain forms the basis of formal and informal justice. If so, a distinctive prediction follows: Laypeople will make decent lawmakers using their sense of justice even when they have no training in law. Further, laypeople will be able to intuitively recreate core features of actual criminal laws from cultures they are totally unfamiliar with.
We devised a study to test those predictions. We showed participants various offenses drawn from actual criminal codes but not the punishments that the law establishes for those offenses.
Some of the offenses we presented came from a modern and culturally familiar society, drawn from Title 18 of the Consolidated Pennsylvania Statutes. But other offenses were truly ancient and culturally foreign. Some participants evaluated offenses from the Laws of Eshnunna, a 3,800-year-old Mesopotamian legal code – one of humanity’s most ancient legal codes. Other participants saw offenses from the Tang Code, a 1,400-year-old legal code from China.
These archaic laws are the next best thing to time travel. They are like fossils that preserve the legal thinking of ancient lawmakers.
To give some examples, some of the Eshnunna offenses shown to participants included: biting out the eye of another man, seizing a boat fraudulently and failing to keep one’s aggressive ox in check, resulting in a slave being killed by the ox. Such…
