Sociology

IQ/Hard; Defaults: IQ-6, Anthropology-3, or Psychology-4.

This is the study of societies and social relationships. A successful skill roll lets you judge how well a large group of people will work together; deduce the social pressures contributing to a crime wave, revolution, war, etc.; or predict the most probable out- come of dissimilar societies coming into contact.

Source: GURPS 4th - Basic Set - Combined, page 223