Investigating (sequential) unit asking: An unsuccessful quest for scope sensitivity in willingness to donate judgments

People exhibit scope insensitivity: Their expressed valuation of a problem is not proportionate with its scope or size. To address scope insensitivity in charitable giving, Hsee et al. (2013) developed the (Classical) Unit Asking technique, where people are first asked how much they are willing to donate to support a single individual, followed by how much they are willing to donate to support a group of individuals. In this paper, we explored the mechanisms, extensions, and limitations of the technique. In particular, we investigated an extension of the technique, which we call Sequential Unit Asking (SUA). SUA asks people a series of willingness-to-donate questions, in which the number of individuals to be helped increases in a stepwise manner until it reaches the total group size. Across four studies investigating donation judgments (total $N=2045$), we did not find evidence that willingness to donate (WTD) judgments to the total group increased with larger groups. Instead, our results suggest that Unit Asking (sequential or classical) increases donation amounts only through a single one-off boost. Further, we find evidence in three out of four studies that the SUA extension increases WTD judgments over Classical Unit Asking. In a fifth study ( $N=537$) using a contingent valuation design (instead of donation judgments), we find scope sensitivity using all asking techniques. We conclude that, while it is difficult to create scope sensitivity in WTD judgments, SUA should be considered a promising approach to increase charitable donations.