We report findings from a national telephone survey on levels of knowledge about and attitudes toward nanotechnology that demonstrate how people make decisions about emerging technologies. Our findings confirm previous research that suggests that people form opinions and attitudes even in the absence of relevant scientific or policy-related information. In fact, our data show that cognitive shortcuts or heuristics – often provided by mass media – are currently a key factor in influencing how the public thinks about nanotechnology and about its risks and benefits, and in determining the level of support among the public for further funding for research in this area.