Ever wonder why we feel guilt? What’s the point of this emotion and how did it develop in humans? Using evolutionary psychology we can shed some light on this mystery.

Suppose your group’s hunting party is away catching boar in the jungle, and you begin to eye your vacant neighbor’s hut for items he might not notice missing. After stealing some spearheads and berries, you feel something wrong: a bit of sickness in your stomach, heaviness in the chest, some anxiety and restlessness. This is the feeling of guilt. No one has witnessed your crime and the act will likely go without future reprisal, but internal signals are clearly messaging that you did something wrong.

From an evolutionary standpoint, you might think that those who make good thieves, or routinely break other societal rules, should be the fittest. As in, thieving, cheating and lying tendencies should increase one’s access to all kinds of resources, resulting in increased survivability and the ability to produce more offspring. But clearly, guilt is a very widespread trait in the population today, so somehow those who were not affected or capable of this emotion were mostly wiped out of the gene pool.

The explanation is that our ancestors lived among small groups, in hostile environments and were completely dependent on each other for survival. Those who regularly cheated, lied or stole from other clan members were eventually caught and ostracized, which would of been a death sentence, and those who didn’t have these tendencies likely showed better restraint over their temptations, and thrived.

Guilt is a powerful form of self-punishment, and a valuable trait that increases a person’s fitness by deterring future reoccurrences of a behavior that could be seen as undesirable to the community. Over many generations, individuals who were especially prone to this emotion were more likely to form stronger social bonds, survive to adulthood, and produce offspring, thus creating the population we have today that widely expresses this trait.

Does this explanation seem plausible? Do you know an exception — someone who seemingly lacks the capacity for feeling guilt or shame?