Theories of the diffusion of ideas in social psychology converge on the assumption that shared beliefs (e.g., social representations, rumours and legends) propagate because they address the needs or concerns of social groups. But little empirical research exists demonstrating this link. We report three media studies of the diffusion of a scientific legend as a particular kind of shared belief. We studied the Mozart effect (ME), the idea that listening to classical music enhances intelligence. Study 1 showed that the ME elicited more persistent media attention than other science reports and this attention increased when the ME was manifested in events outside of science. Study 2 suggested that diffusion of the ME may have responded to varying levels of collective anxiety. Study 3 demonstrated how the content of the ME evolved during diffusion. The results provide evidence for the functionality of diffusion of ideas and initial elements for a model of the emergence and evolution of scientific legends.