<p>Dystopian AI tropes, grounded in science fiction, are pervasive in popular culture, but the effects of these narratives on lay orientations toward socio-technological futures remain under-researched. The article distinguishes between imagination (what people can envision) and expectations (what they think is likely), and explores the influence of science fiction on both. Drawing on semi-structured interviews with young adults, we identify an “AI futures imagination gap”: an asymmetry in people’s imaginative capacity, whereby dystopian sociotechnical futures associated with AI and robotics are vivid, coherent, easily elaborated, and often articulated through sci-fi-inflected narrative templates, while utopian sociotechnical alternatives remain abstract, fragmented, and difficult to articulate. Science fiction also shaped expectations in a more indirect way. Participants did not usually consider fictional scenarios as straightforwardly predicting the future, but instead posited that less extreme and modified forms of the problems depicted could be real issues. The findings suggest the problem is not a lack of will to imagine better futures, but a lack of narrative templates: dystopian futures were richly resourced by science fiction, but positive futures lacked comparable support from sci-fi or other cultural sources. This imagination gap may constrain the possibilities of public deliberation and limit democratic capacities for shaping socially desirable futures involving AI. Participatory futures methods such as backcasting may help to cultivate more socially grounded, politically plural and non-technocratic visions of alternative positive sociotechnical orders, but their impacts depend on whether such visions circulate beyond expert settings and enter wider public and policy debate.</p>