Encouraging Improvisation

Dulcimers provide a great opportunity for players to improvise- because nothing sounds bad with a diatonic scale. Here are a few ideas. Once students are comfortable playing simple tunes on the melody string, and comfortable strumming quarter notes (one way) and eigth note (two way strums) you can play "Pass the measure". In a circle, each participant in turn plays a four bar measure, reacting to the measure played by the person who just played before them. Sometimes best to have the leader respond between each player.
When students are comfortable with this, suggest they pair off for "melodic conversations" where they play a measure or two, then hear their partner's response, then respond in turn, passing ideas back and forth and letting them evolve. I've also sent adult students off to compose a few measures that reflect how they are feeling or where they are in their life, then return to share these (if they wish) in small groups.