Adaptive systems react to changes in their environment by changing their behavior. Identifying these needed adaptations is very difficult, but central to requirements elicitation for adaptive systems. As the necessary or potential adaptations are typically not obvious to the stakeholders, the problem is how to effectively elicit adaptation-relevant information. One approach is to use creativity techniques to support the systematic identification and elicitation of adaptation requirements. In particular, here, we analyze a set of creativity triggers defined for systematic exploration of potential adaptation requirements. We compare these triggers with brainstorming as a baseline in a controlled experiment with 85 master students. The results indicate that the proposed triggers are suitable for the efficient elicitation of adaptive requirements and that the 15 trigger questions produce significantly more requirements fragments than solo brainstorming.