Is bigger always better? The unit effect in carbon emissions information

According to Pandelaere et al. (2011), bigger numbers of units in quantitative attribute information lead to greater perceived attribute differences, making it more likely that consumers will choose a higher-attribute option. We replicate this unit effect for the carbon emissions metrics displayed in car advertisements, and extend it to show that highly numerate individuals, who are supposed to be more effective decision-makers, may actually be more prone to numerosity heuristics.