On what basis do people provide acceptability or ‘goodness’ judgements for deontic conditional rules of the form if p then must q and if p then may q? Using a decision theoretic analysis, Over et al. (2004) propose that such conditionals are judged as acceptable to the extent that the p&q possibility is preferred to the p¬-q possibility. Their empirical evidence upholds this ‘conditional expected utility’ (CEU) prediction for conditional obligations and permissions relating to everyday activities (e.g., If you wash the dishes then you must wear rubber gloves). We report two experiments examining Over at al.’s CEU hypothesis in relation to real-world deontic rules concerning everyday health and safety issues (e.g., If you are in a moving car then you must have your safety-belt fastened). We propose that Over et al.’s CEU hypothesis provides a compelling account of our findings.
