This paper synthesizes findings from three studies to answer a general question: What do casual, adult visitors learn about science from their science-related experiences in free-choice settings? Specifically we asked whether there are changes in how people think about science in their daily lives, the nature and use of scientific knowledge, and its communication by scientists. The three studies involved samples of visitors to an interactive science centre, visitors to a traditional natural history museum, and attendees at a series of public lectures, each given by an expert scientist in human genetics. Pretest and post-test data collected by parallel questionnaires indicated that, despite the different nature of their experience in the three different settings, participants became more positive about the value of science and the work done by scientists and their ability to communicate with the public. At all venues, however, participants became less scientific in their thinking about the nature of scientific knowledge, becoming more likely to believe it to be infallible. The consistency of these findings was surprising, and participants' changed views about the nature of scientific knowledge were unexpected. Possible explanations for theses outcomes were suggested in terms of participants' reasons for attending the venue, the nature of their engagement, and the non-controversial ways in which the exhibitions and lectures were structured. The findings suggest that the educational role of free-choice settings should be considered carefully, particularly with regard to the representation of science. (Contains 4 tables.)