The Exploratorium's Going APE project (APE=Active Prolonged Engagement) developed 30 exhibit designs to encourage visitors to become more cognitively engaged with exhibits--to use exhibits as tools for self-directed exploration, rather than as authoritative demonstrations. To do this, the staff drew on work in the fields of education, visitor research, human factors engineering, computer interface design, and interactive exhibit development at other museums. The project also integrated evaluative research into exhibit development to maximize possibilities for visitor-authored questions