Opinion Paper: The Sound Use of Experimental Hypotheses in Animal Science

This opinion paper argues that well-formulated, testable hypotheses are essential to ensure rigour, transparency, and ethical responsibility in animal science research. Pulina highlights that many studies present aims or justifications rather than true hypotheses, undermining methodological coherence and reproducibility. The article distinguishes between hypothesis-driven and exploratory studies: the former must start with a clear, falsifiable proposition linking variables under defined conditions, while the latter should culminate in hypotheses for future testing. Drawing on Popper’s logic of falsification and Quine and Ullian’s “five virtues” (conservatism, modesty, simplicity, generality, refutability), Pulina argues that hypotheses should be logically grounded, biologically meaningful, and aligned with prior knowledge. A ten-step checklist is proposed to guide researchers in formulating robust hypotheses, covering question definition, literature review, plausible mechanisms, variable identification, scope of inference, falsifiability, ethical feasibility, and biological relevance. The paper also warns against common issues such as “spin,” misuse of statistical significance, and neglect of effect size and biological importance. To foster good practices, the author recommends: Journals should require explicit hypotheses in hypothesis-driven studies and clearly frame exploratory findings as proposals for later testing. Funding bodies should prioritise projects with precise and biologically grounded hypotheses. Research training should emphasise the epistemological and methodological roles of hypotheses. Pulina concludes that placing hypotheses at the centre of experimental design enhances scientific integrity, reproducibility, and the ethical justification of studies, ultimately improving the reliability of animal science