affect: positive, negative, and neutral. Both spontaneous comments and comments elicited by researchers have similarly been coded to show differences in emotional response during museum visits. Clipman (2005), for example, used the Positive and Negative Affect Schedule to show that visitors leaving a Chihuly exhibit of art glass reported being more happy and inspired than visitors to a quilting exhibit in the same museum (Clipman, 2005). Myers, Saunders, and Birjulin (2004) used Likert and semantic-differential measures to show that zoo visitors had stronger emotional responses to gorillas than other animals on display. Raphling and Serrell (1993) asked visitors to complete the sentence “It reminded me that …” as a part of an exit questionnaire for exhibitions on a range of topics, and they reported that this prompt tends to elicit affective responses from visitors, including wonderment, imagining, reminiscences, convictions, and even spiritual connection (such as references to the power of God or nature).
In studies of informal learning, interest and related positive affect are also often inferred on the basis of behavior displayed. That is, participants who seem engaged in informal learning activities are presumed to be interested. In this sense, interest and positive affect are often not treated as outcomes, but rather as preconditions for engagement. Studies that document children spontaneously asking “why” questions, for example, take as a given that children are curious about, interested in, and positively predisposed to engaging in activity that entails learning about the natural world (e.g., Heath, 1999). Studies that focus on adult behavior, such as engaging in hobbies, are predicated on a similar assumption—that interest can be assumed for the people and the context being studied (e.g., Azevedo, 2006). A meta-analysis of the types of naturally occurring behavior thought to provide evidence of individuals’ interest in informal learning activities could be useful for developing systematic approaches to studying interest. Such an analysis also could be useful in showing how interest is displayed and valued among participants in informal learning environments, providing an understanding of interest as it emerges and is made meaningful in social interaction.
As progressively more research shows, learning about natural phenomena involves ordinary, everyday experiences for human beings from the earliest ages (National Research Council, 2007). The types of experiences common across the spectrum of informal environments, including everyday settings, do more than provide enjoyment and engagement: they provide substance on which more systematic and coherent conceptual understanding and content structures can be built. Multiple models exist of the ways in which scientific understanding is built over time. Some (e.g., Vosniadou