1. a social process that occurs when a group, by acting in concert, achieves an outcome that is superior to what would be achieved by the most capable member or by any simple pooling of individual member efforts, often summarized by the phrases “the whole is greater than the sum of the parts” or “2 + 2 = 5.” See also assembly bonus effect.

2. in Raymond B. Cattell’s group psychology, the sum of all individual members’ energy going into the group: that is, the total available group energy or investment in itself.