Joshua Lewis is a third-year doctoral student in the Decision Processes group, interested in judgment and decision making and consumer behavior.
He researches how a reluctance to make extreme estimates contributes to anchoring effects (Lewis, Gaertig & Simmons, forthcoming in Psychological Science); how cost-effectiveness information can make people donate inefficiently when framed as “cost per unit”, (Lewis & Small, working paper), how prospect theory should be adjusted to account for people’s treatment of prices (Lewis, Rees-Jones, Simonsohn, & Simmons, working paper) and how anticipated outcome bias drives motivation to achieve uncertain outcomes (Lewis & Simmons, working paper).
Other research streams concern how forgone options act as reference points (Green & Lewis, working paper), and how the best strategies to maintain trust depend upon relationship type (with Moore, Levine, & Schweitzer, working paper).
Joshua was born and raised in the UK. Before joining Wharton, he worked in London as a fixed income analyst for Henderson Global Investors. He also completed a bachelor’s degree in Economics from the University of Warwick, and worked as a researcher for the Warwick Policy Lab.
Abstract: When estimating unknown quantities, people insufficiently adjust from values they have previously considered, a phenomenon known as anchoring. We suggest that anchoring is at least partially caused by a desire to avoid making extreme adjustments. In seven studies (N = 5,279), we found that transparently irrelevant cues of extremeness influenced people’s adjustments from anchors. In Studies 1-6, participants were less likely to adjust beyond a particular amount when that amount was closer to the maximum allowable adjustment. For example, in Study 5, participants were less likely to adjust by at least 6 units when they were allowed to adjust by a maximum of 6 units than by a maximum of 15 units. In Study 7, participants adjusted less after considering whether an outcome would be within a smaller distance of the anchor. These results suggest that anchoring effects may reflect a desire to avoid adjustments that feel too extreme.