Re-evaluating the Numerical-Perceptual Distinction in the Attraction Effect

A widely studied cognitive bias in decision-making is the attraction effect, in which introducing a clearly inferior decoy option into a binary choice set increases the likelihood of selecting the dominating option (target) over the competitor. While this effect is robust with numerical stimuli, findings with perceptual stimuli have been inconsistent, with some recent studies even reporting a negative attraction effect. We argue that this distinction between numerical and perceptual stimuli is superficial, and that choice behavior is better explained by the inter-attribute relationships. In two experiments, we demonstrated positive attraction effects using combined perceptual-numerical stimuli and both positive and null effects with numerical stimuli by manipulating the asymmetry in pairwise comparison difficulty. The numerical stimuli used in Experiment 2 leveraged the findings from fraction research. Together, our results challenge the numerical-perceptual distinction and support a universal cognitive mechanism underlying the attraction effect.