THE EFFECT OF COMMITMENT ON ADOPTION AND DIFFUSION OF GRASS CYCLING

Using a design that also permitted an assessment of the extent to whic h any increase in grass-cycling behavior diffused to the neighbors of treated participants, two types of commitment strategies for promoting residential grass cycling (i.e., not bagging grass clippings) were in vestigated. Baseline data were collected over a period of 4 weeks to d etermine which residents in each of three homogeneous neighborhoods ba gged grass clippings for curbside pickup. A total of 558 houses observ ed to bag grass clippings during this period were included as particip ants in the experiment. Following baseline, the neighborhoods were ran domly assigned to one of three conditions. Results indicated that part icipants who made a commitment to grass cycle and to talk to their nei ghbors had grass bags present significantly less often than either the commitment-only or control participants. This effect was present duri ng the 4-week intervention period and also was sustained during an imm ediate 4-week follow-up period and a delayed 4-week follow-up period 1 2 months later. There also was a diffusion effect in which the neighbo rs of targeted participants showed significantly more grass cycling th an controls, and this effect continued to increase through the 1-year follow-up measure. On the other hand, neither commitment-only particip ants nor their neighbors differed from controls during any period of t he experiment.