Evaluated the effect of commitment (CM) on paper recycling. Exp 1 asked 24 elderly residents of a retirement home to sign a 4-wk group CM pledge to recycle paper. During this intervention, Ss recycled 47% more paper than they had during baseline. Ss continued to recycle at this level during a 4-wk follow-up, when the group CM was removed. Exp 2 evaluated the effectiveness of group CM, individual CM, and token reinforcers on paper recycling in 87 students in a college dormitory. Ss recycled 3-5 times more paper than controls during the 4-wk intervention. However, in the 3-wk follow-up, when treatments were removed, only individually commited Ss continued to recycle significantly more paper than controls.