The psychology behind moral judgments
Moral Foundations Theory identifies five (or six) underlying intuitions that guide human moral judgment across cultures. Care concerns preventing suffering and promoting welfare. Fairness tracks justice and proportional reciprocity. Loyalty values solidarity and group cohesion. Authority respects tradition and social hierarchy. Sanctity (or sanctimoniousness) treats some domains as sacred or contaminated. These foundations are intuitive, not reasoned conclusions. Most people feel them before they can articulate them.
Research suggests conservatives value all five foundations roughly equally, while liberals prioritize care and fairness while minimizing loyalty, authority, and sanctity. This difference explains why liberals and conservatives talk past each other on issues like gun control (liberty vs. safety), immigration (fairness to newcomers vs. loyalty to existing citizens), or sexuality (harm/fairness vs. sanctity).
Implications for moral understanding
If moral judgments rest on distinct foundations, then persuasion requires addressing the foundations that actually move your audience, not just the ones you prioritize. A conservative opposed to welfare spending on fairness grounds cares about proportionality and reciprocity. Arguing that the program reduces suffering (care) will not convince. Arguing that current systems reward idleness unfairly (fairness) might.
Understanding Moral Foundations theory also explains why different cultures prohibit different behaviors. One culture enforces strict food rules from a sanctity foundation, another forbids the same food on fairness grounds (resource preservation). Both systems feel deeply natural to those raised in them. Cross-cultural moral dialogue requires appreciating which foundations animate each position, not assuming bad faith or stupidity.