This study aims to investigate the use of informal reasoning and the nature of science (NOS) in resolving two socio-scientific issues (SSI): proximal (Processed Foods) and distal (Golden Rice). Nineteen pre-service science teachers were purposefully selected to participate in this instrumental multi-case qualitative study. Participants were individually interviewed about two separate SSI scenarios prepared with a parallel general theme, balanced evidence, and structure. The resulting data was analyzed deductively using Sadler and Zeidler's (2005) established categories to identify informal reasoning patterns exhibited by the participants. Moreover, this study examined the use of four aspects of NOS understanding: risk analysis in science, social embeddedness of science, tentative and subjective nature of scientific knowledge, classified as naive, mixed, and informed. Findings revealed multidimensional reasoning, with distinct patterns emerging for proximal (Processed Foods) and distal (Golden Rice) issues, and variations in NOS understanding. Specifically, participants displayed evidence-based rationalistic thinking more often in distal SSI (Golden Rice), while displaying care-based emotive informal reasoning more often in proximal SSI (Processed Foods). In addition, the results indicated that participants tend to employ more informed understandings regarding the four aspects of NOS in the distal context than in the proximal one. The findings are discussed, highlighting their implications for preparing effective SSI cases to use in classroom instruction and scaffolding that needs to be provided for effective engagement with SSI cases.
