A lottery was implemented to encourage the elderly clients of a residential home to use activity materials any time they wished, independently of staff intervention and the institutional routine of the home. During baseline, there were minimal levels of independent use of activity materials by residents. Various conditions were implemented but only the introduction of a ł20 lottery prize brought about a significant increase in the frequency of independent use of activity materials. A follow-up suggested that the reinforcing properties of the activity materials themselves eventually maintained the target behavior.