The Righteous Mind by Jonathan Haidt is a book about the psychology of morality. Haidt argues that humans are intuitively moral, and that our moral judgments are based on gut feelings rather than reason. He divides morality into six different moral foundations: care/harm, fairness/cheating, loyalty/betrayal, authority/subversion, sanctity/degradation, and liberty/oppression.
Haidt argues that liberals tend to focus on the first two foundations (care/harm and fairness/cheating), while conservatives tend to focus on all six. This is why liberals and conservatives often see things very differently when it comes to morality.
The left tends to emphasize harm prevention while the right emphasizes fairness. This explains why the left is more supportive of social programs and the right is more supportive of free markets. He uses social science research to support his argument.
Haidt also argues that humans are tribal animals and that we are hardwired to form groups. This instinct explains why people are more likely to donate to charity if they know the donor personally or if the charity is associated with their religious or political group.
One of the most important things to take away from The Righteous Mind is that we should be open to the idea that other people may see things differently than we do, and that there is value in different perspectives. We should also be open to the idea that our gut feelings may not always be right, and that we should try to use reason when making moral judgments.