The mass shooting in Las Vegas has become yet another example of human capacity for evil. Almost immediately, people cried for gun control, greater checks on assault weapons and measures to increase hotel security.

But what about calls for increasing levels of empathy in society?

Empathy has long been a core belief of many major religions around the world. The Abrahamic religions, Hinduism and Buddhism all emphasize kindness and compassion.

It’s also an instinct scientists say humans can learn to hone.

Empathy means to understand another person’s thoughts, feelings or state of being. Research also shows that other mammals are capable of emotional contagion, where an emotion transfers from individual to individual.

Stephanie Preston, a psychology professor at the University of Michigan, recently co-authored a paper discussing the latest evidence on empathy research in humans and other mammals.

Apes such as chimpanzees and bonobos are able to develop a so-called theory of mind, which means they can take into account the perspective of another animal, for example by offering comfort and consolation. Empathetic capacities have also been observed in mice, birds and ants. Even rats will have emotional responses when they see other rats in pain.

“These emotional responses will even lead to the rodents helping the victim, so rats have been shown to help one another,” said Preston. “If one is trapped in a box in a cage, the other rat will work to free the rat. Across species, there’s different capacities for empathy.”

There are many biological processes behind empathy. Mirror neurons are specific neural cells that fire both when one performs an action and when one observes another person performing that same action.

Mirror neurons are only part of the story, though. Memories help relate on a conceptual level to what the other person is experiencing, providing context as to how a person might be feeling.

“There’s all these distributed neural representations based on your own past experiences that helps you relate to the experience yourself,” said Preston. “If someone is going through something difficult and you’ve experienced that yourself, you are more able to relate directly to how they feel.”

What’s more, those who are highly altruistic have larger amygdalas, which are parts of the brain that are responsible for emotions, survival instincts and memory.

These people are more responsive to people’s fears and are better able to identify people’s emotional expressions, said Abigail Marsh, a psychology professor at Georgetown University who worked on a study earlier this year exploring why kidney donors are more altruistic.

“There’s some evidence suggesting that having had really impactful life experiences helps you empathize with other people,” Marsh said. “There’s also evidence that larger cultural and populational variables like well-being and flourishing cause people to be more empathetic to strangers.”

Researchers say empathy is not only a biological instinct, but also a skill human beings can learn and improve upon. If people practice it, their body will respond to that, and it will become second nature over time.

Preston, who has studied how people develop altruism, said mammals evolved to care for their offspring. Mammalian infants take longer to develop before they become independent. Over time, mammals adapted, responding to distress not only from their offspring but also from kin, friends or other individuals in their social groups.

Preston is now working on a brain imaging study in which subjects lie in an MRI machine as they are shown descriptions of different charities that need monetary donations. She found that people tend to donate more when the person needing help is either a child or needs immediate assistance.

Just how religion plays into our biological impulse for empathy is not yet clear. One study from the University of Chicago shows that religious upbringing is associated with less altruism. Other studies have shown the contrary; a University of Warsaw study found that religious beliefs are positively associated with empathy, as empathic skills are crucial factors for religion.

Not only do belief systems ask followers to understand other people’s feelings, but also to take action and help others. People and animals tend to care about their family, friends and others in their social groups. That’s why religions often elevate human empathy.

“It works to enhance certain kinds of emotional states like fruits of the spirit, kindness, joy and so forth,” said Stephen Post, professor of family, population and preventive medicine at Stony Brook University, who studies religion and health care. “That’s what a lot of spirituality is —  a sense for oneness and divine power of some kind that can sway us towards warm and loving emotions, away from destructive and hurtful ones.”

Major religions and philosophies around the world have teachings on empathy that ask followers to identify with the feelings of others:

  • “You shall not oppress a stranger, for you know the heart of a stranger, because you were strangers in the land of Egypt,” Exodus 23:9.
  • “Love your enemies and pray for those who persecute you,” Matthew 5:44.
  •  “Hurt not others with that which pains yourself,” the Udanavarga, an early Buddhist collection of verses.

In religion, empathy is often among the highest of virtues.

“Empathy in religion is not just an intellectual notion or a feeling, and it’s not just refraining from acting unkindly towards others. It’s also a call to action to show kindness towards others,” said Yudit Greenberg, religious studies professor at Rollins College. “It also implies an action.”

And some scientists believe empathy can be cultivated.

Marsh, who wrote a book called The Fear Factor, argues that mass shootings notwithstanding, people are becoming more compassionate over time. According to the Charities Aid Foundation, altruistic behavior increases every year.

Marsh said horrific acts of violence do not have much to do with empathy, as they are committed by people who are either suffering from mental illness or experiencing outbursts of rage directed at specific people, or people generally. In these cases, rage can overpower compassion.

To develop empathy, Marsh suggested compassion meditation, which involves training oneself to foster and extend feelings of care and compassion to ever-wider circles of people.

Another way, said Greenberg, is to participate in service-learning projects and community engagement courses, which can help people develop empathy toward people outside their normal social groups.

“Without empathy, we lose our moral compass,” Greenberg added. “With all the tragedies, natural disasters, as well as human-made disasters, of course we feel the horrible pain of families and friends that are involved in all of these horrible, horrible events. It makes me think of the extent to which we not just have empathy, but also act on it.”