Why do scientists disagree? Explaining and improving measures of the perceived causes of scientific disputes.

There has been increasing attention to understanding how laypeople explain disagreements among scientists. In this article, we evaluate the factorial validity and scale/item functioning of a Science Dispute Reasons scale (Study 1) and test specific hypotheses about demographic, individual difference, and topic-related variables that may explain why some reasons are perceived to be more likely than others (Study 2). The final scale included 17 items grouped into three reason factors (Process/Competence, Interests/Values, and Complexity/Uncertainty), which is largely consistent with previous research. We find a mixed pattern of global and specific impacts on reason likelihood ratings from a range of variables including political ideology and conspiracist ideation (primary mediated through perceived credibility of science), science knowledge, and topic-related variables such as knowledge of and care about the dispute in question. Overall, science dispute reasons appear to be more strongly driven by attitudes and worldviews as opposed to objective knowledge and skills. These findings represent progress in understanding lay perceptions of the causes of scientific disputes, although much work remains. We discuss the implications of this work and directions for future research.