The decoy effect only works when the number of options is less than six

The decoy effect is a well‐documented source of violation of elements of demand theory. We experimentally demonstrate that the decoy effect only works when the number of options is limited (specifically not more than five). This is because, with more and more options, it may get difficult for consumers to spot the decoy (against which a Pareto dominant option is made to look more attractive), rendering the decoy effect ineffective. Identifying that the decoy effect works because it facilitates easier choice‐making, we observe that the difficulty in choice‐making with or without the decoy is statistically the same when the number of options to choose from is six or more.