Why do people do things that benefit others but disadvantage themselves?

On the surface, altruism seems to be inconsistent with the process of evolution. If we view evolution as a competition in which the winners survive and reproduce at the expense of the losers, then selfishness should create an evolutionary advantage.

In fact, this interpretation of Darwin’s concept of natural selection has been used to justify social policies that hurt those who are already disadvantaged (because of income, class, nationality or race), with the idea that the laws of nature dictate that those who are less able to survive should not survive.

If altruism were at odds with evolution, then it would be very rare.

But altruism can be found throughout the animal kingdom.

In the Origin of Species, Darwin points out the apparent contradiction of worker bees risking their lives to protect their hive. He explains this by saying that “selection can be applied to the family, as well as the individual.”

In the Descent of Man, he states that animals that live in social groups have warning systems, in which one member of the group signals to the rest of the group when it discovers a threat, exposing itself to danger in the process, and that sometimes a few animals will risk their own lives fighting to defend their entire group.

Biologists such as Fisher, Haldane and Hamilton further developed the idea of kin selection – that animals will sometimes behave in ways that are harmful to themselves as individuals in order to benefit their relatives.

In The Selfish Gene, Dawkins states that kin selection makes sense once you understand that, ultimately, evolution is not about the survival of individuals but about the survival of genes. When you help your siblings (or other close relatives with whom you share a large percentage of genetic material) to survive, you increase the chances that your genetic material will continue to be replicated.

Humans and other animals, however, do not confine acts of altruism to their immediate genetic relations, or even their own species. We would not be surprised by a story of a dog risking its life for its owner.

There have been anecdotes, from ancient times to the present day, of dolphins surrounding humans to protect them from sharks and pushing drowning humans to the water’s surface so that they can breathe.

And human beings are known for treating cats, dogs and members of various other species like their own children.

Since it is not always possible to determine who is one’s kin, evolution may have led some animals to develop the predilection to help other animals that are part of its social group (a dog sees itself as part of its owners “pack”) or that are like them in some way (a dolphin identifies humans as well as members of its own species as creatures that need air to survive). This can make decision-making quicker, which is essential when there is a threat. If it shares your home, shares food with you, plays with you and cuddles you, protect it. If a shark is swimming toward it, form a circle around it. If it appears helpless and hungry, feed it.

Altruistic behavior in non-humans has been seen in the laboratory. In, an experiment studying altruism in rats, which was performed in 2011, pairs of rats were placed in pens, with one rat trapped in a cage while the other rat was able to roam free. In the majority of cases, the free rat learned how to open the cage and then liberated the other rat. The free rats did not open empty cages or cages that had toy rats – they specifically chose to help their fellow rats.

When the free rats were given the choice of freeing the trapped rat or opening a cage that was full of chocolate (a favorite rat treat), most rats opened both cages, and then shared their chocolate with the other rat.

Researchers at the University of Zurich have just discovered a connection between altruism in humans and the structure of the brain. In an experiment, subjects played a game in which they had an opportunity to divide money between themselves and another player. Subjects who behaved more altruistically had more gray matter in the right temporoparietal junction (TPJ) than those who behaved more selfishly.

The right TPJ is associated with the development of theory of mind – the ability to understand the mental state of another. Understanding another’s mental state can lead you to develop empathy toward them, which can in turn cause you to put their needs above your own.

The natural tendency toward altruism has philosophical and political implications. The ancient Golden Rule – “Treat others as you wish to be treated” – can be seen as a manifestation of natural altruistic impulses. When you put someone else’s wellbeing above your own, you help to ensure the survival of genetic material that may be your own. (This might explain why the Golden Rule is sometimes forgotten when there is an opportunity to make a sacrifice for someone of a different nationality or ethnic background.)

Kant’s dictate that you should only perform acts that could become universal laws – for example, you should not steal because if everybody were allowed to take whatever they wanted when they wanted it, there would be chaos, and therefore stealing could not be allowed universally – reflect a concern for the well-being of the group above that of the individual.

The Enlightenment theory that human societies were formed by social contracts, in which people gave up some of their individual liberties in order to ensure the protection of the group, is also reflective of natural examples – the vervet monkey who gives an alarm call to warn other monkeys that a predator is near gives up his “right” to protect himself from by danger by hiding quietly.

There are implications regarding how we treat non-human animals. If other animals behave altruistically toward others, do we have a moral obligation to behave altruistically toward them?

If it is possible to identify how altruistic a person is by examining their brain, as the University of Zurich study suggests, then will we someday define people as altruistic or selfish before we have observed their actions?

Will reports of the amount of gray matter in a defendant’s right TPJ be used as evidence in criminal proceedings? “Your Honor, my client could not have stolen that bracelet. His fMRI shows that he is not a selfish person.”

As human brains are plastic, perhaps children’s “altruism levels” will be tested in school to ensure that they have the right level of altruism in adulthood.

If the gray matter in a child’s right TPJ is deemed too low, she might be sent to special classes where she learns how to share and get along with others better. Conversely, if a child is thought to be “too altruistic”, based on an examination of his brain, perhaps he will be taught to stand up for himself more and avoid being bullied.

Of course, many factors will be involved in determining how altruistically a person will behave in a given situation, including past experiences, their relationship with the other person, and whether there is a perceived possibility of long-term benefit, and it is extremely unlikely that we will be able to predict whether someone will be generous or selfish by looking at one small part of that person’s brain.

Nevertheless, these are interesting possibilities.