shower effect
A marketing theory: placing popular items on upper floors draws customers upward, and they browse lower floors on the way down, increasing overall sales. Compare 噴水効果 (fountain effect), which describes a similar flow from lower to upper floors.
See also: 噴水効果
Department stores sometimes place popular items on upper floors to take advantage of the shower effect.
From English 'shower' + 効果 (effect). The term likens customer flow to water cascading down from upper floors.