A T-group or training group (sometimes also referred to as sensitivity-training group, human relations training group or encounter group) is a form of group training where participants (typically between eight and fifteen people) learn about themselves (and about small group processes in general) through their interaction with each other. They use feedback, problem solving, and role play to gain insights into themselves, others, and groups.
Experimental studies have been undertaken with the aim of determining what effects, if any, participating in a T-group has on the participants. For example, a 1975 article by Nancy E. Adler and Daniel Goleman[1] concluded that "Students who had participated in a T-group showed significantly more change toward their selected goal than those who had not." Carl Rogers described sensitivity training groups as "...the most significant social invention of the century".[2]