He studies morality, its emotional foundations, cultural variations, and developmental course. His early research on moral intuition changed the field of moral psychology, moving it away from its previous focus on moral reasoning.
His current work on the "five foundations of morality" is changing the field again, moving it beyond its traditional focus on issues of harm and fairness, and drawing attention to the moral issues that animate political conservatives and religious believers.
Haidt has published 75 academic articles, in Science, Psychological Review, and other leading journals. He is the co-editor of Flourishing: Positive Psychology and the Life Well Lived, and is the author of The Happiness Hypothesis: Finding Modern Truth in Ancient Wisdom.