Switching attention incurs a cost for counterfactual conditional inferences

People often reason hypothetically in everyday life, for example, from conditionals such as ‘if there is a circle there is a triangle’. They find some inferences easy, e.g., ‘there is a circle, therefore there is a triangle’, and others difficult, e.g., ‘there is no triangle, therefore there is no circle’. We report an experiment that applies attention switching methods to reasoning from counterfactuals, e.g., ‘if there had been a circle, there would have been a triangle’. The results show that even the simplest inference is adversely affected if reasoners must switch attention from a preceding difficult inference. Asymmetrical inference switching costs occur not only for indicative but also for counterfactual conditionals: the easy inference takes longer when reasoners must switch attention from the difficult one compared to when they switch attention from another easy one; the difficult inference remains difficult whether reasoners switch from an easy or difficult inference.