Jonathan David Haidt (; born October 19, 1963) is an American social psychologist and author. He is the Thomas Cooley Professor of Ethical Leadership at the New York University Stern School of Business. Haidt's main areas of study are the psychology of morality and moral emotions. Haidt's main scientific contributions come from the psychological field of moral foundations theory, which attempts to explain the evolutionary origins of human moral reasoning on the basis of innate, gut feelings rather than logic and reason. The theory was later extended to explain the different moral reasoning and how they relate to political ideology, with different political orientations prioritizing different sets of morals. The research served as a foundation for future books on various topics. Haidt has written multiple books for general audiences, including The Happiness Hypothesis (2006) examining the relationship between ancient philosophies and modern science, The Righteous Mind (2012) on moral politics, and The Coddling of the American Mind (2018) on rising political polarization, mental health, and college culture. In 2024, he published The Anxious Generation, arguing that the rise of smartphones and overprotective parenting has led to a "rewiring" of childhood and increased mental illness.