[Namsan Ddalggakbari] Why That Person Is Kind, According to a Neuroscientist

In 2000, a patient with pedophilia was arrested on charges of collecting child pornography and sexually assaulting his stepdaughter. However, during the investigation, he complained of severe headaches, and upon examination, a large cancerous tumor was found in the prefrontal cortex of his brain. Remarkably, after undergoing surgery to remove the tumor, his pedophilic symptoms disappeared. A few months later, however, he began collecting child pornography again, and a re-examination of his brain revealed that the previously removed tumor had regrown. This serves as evidence that specific areas of the brain influence behavioral tendencies.

Professor Kim Hak-jin of Korea University’s Department of Psychology, author of the book The Secret Brain Structure of Altruists, introduces this case as part of neuroethics research exploring the relationship between the brain (ventromedial prefrontal cortex) and moral judgment. It is related to the well-known “Trolley Dilemma.” This dilemma begins with the assumption that one must decide the direction of a trolley speeding down a track: one track has five workers, and the other has one. Most people naturally choose to sacrifice one to save five. However, when the choice involves deliberately pushing someone onto the tracks to stop the trolley, most people hesitate. Only those with damage to the ventromedial prefrontal cortex made the seemingly rational choice to save five without hesitation. This suggests that people with normal brain function are more likely to be altruistic.

Individuals with damage to the ventromedial prefrontal cortex show serious impairments in social behavior, failing to consider subtle changing factors appropriately. According to the book, during interviews with the author, such individuals exhibited overly candid behavior, confessing to affairs or sexual misconduct. They also failed to read social cues, often staring intensely or displaying aggressive behavior, frequently crossing social boundaries.

According to the author, a normal brain is more attracted to secondary rewards than primary rewards. If food is a primary reward, money is a secondary reward. Food can satisfy hunger, but money allows one to enjoy many more things, including food. The key here is self-control. Without self-control, one focuses on primary rewards and may fall into addiction, only seeing the immediate moment. However, with a broader perspective, one can make wise decisions (altruism). This is why sound judgment is essential. The author explains, “The brain is naturally more attracted to secondary rewards than primary ones. This tendency is natural and, in the long term, is a favorable choice that increases survival chances. Humans generally shift their focus from primary to secondary rewards gradually through countless experiences during development.”

The author also derives the cause of altruism from humans’ reputation instinct. Since receiving good evaluations from others is advantageous for survival, people strive to gain a good reputation, which in turn realizes altruism. In one experiment, people positively evaluated those who rated their friends higher than themselves and negatively viewed the opposite. This suggests that altruism does not lower oneself but rather improves one’s standing. The author states, “When introducing a friend to others, emphasizing positive aspects and avoiding negative ones can be a good strategy to enhance one’s own reputation.”

Altruistic behavior is also linked to the rewards it brings. Just as among Arabian babblers, the bird that takes on the effort of alerting the group to a predator from the highest tree is more likely to become the leader, altruism tends to gain favor from others, making it easier to obtain additional benefits. However, the author mentions Lee Soo-hyun, who sacrificed his life to save a stranger at a train station in Japan, questioning whether such practical benefits can be considered in less than a second. He argues that such practical judgment is so deeply ingrained that it becomes unnecessary to consciously deliberate.

The overarching argument of the book is that altruism is, before being for others, for oneself. Since the ventromedial prefrontal cortex is associated with satisfaction or pleasure from alleviating hunger or pain, it provides strong internal rewards, or external rewards through gaining a good reputation.

The author’s arguments, developed with various examples, are intriguing. They kindly offer an opportunity to reconsider altruism. However, the book is not very approachable in making complex concepts easy to read.

The Secret Brain Structure of Altruists | Written by Kim Hak-jin | Galmaenamu | 304 pages | 17,000 KRW