The leftmost digit change induces a decrease in brain activity related to visuospatial processing: An fMRI study of the price ending effect

Consumers perceive prices that have been slightly reduced from round price as irrationally cheap. This price ending effect is thought to be driven primarily by two factors: the left-digit effect which occurs when a small price drop changes the leftmost digit, and the image effect which stems from the symbolic association of a particular price ending with low prices or sales. Our study aimed to investigate the neural basis of these irrational effects on perceived cheapness using functional magnetic resonance imaging (fMRI). We used five price values in Yen (197, 198, 201, 202, 206; Japanese consumers tend to perceive prices ending in the number 8 as cheap) for fMRI experiment. Participants were asked to rate the price value of a product. The “left-digit effect” was observed based on the deactivation in brain regions associated with visuospatial processing including the left lingual gyrus and posterior middle temporal gyrus, and the right dorsal posterior precuneus and anterior precuneus. From these regions, the degree of deactivation in the right dorsal posterior precuneus was negatively correlated with the irrational perception of cheapness. Furthermore, this region showed negative functional connectivity with the dorsal striatal regions. No regions were found with “the image effect”. Our results suggested that a decrease in activity in the regions associated with visuospatial processing suggests that changes in the leftmost digits alter the level of visuospatial attention towards the price, leading to an underestimation of the payment amount. This reduced attention might activate the dorsal striatum driving unconscious purchasing.