Years, Months, and Days versus 1, 12, and 365: The Influence of Units versus Numbers

Abstract Quantitative changes may be conveyed to consumers using small units (e.g., change in delivery time from 7 to 21 days) or large units (1–3 weeks). Numerosity research suggests that changes are magnified by small (vs. large) units because a change from 7 to 21 (vs. 1–3) seems larger. We introduce a reverse effect that we term unitosity: changes are magnified by large (vs. small) units because a change of weeks (vs. days) seems larger. We show that numerosity reverses to unitosity when relative salience shifts from numbers to units (study 1). Then, arguing that numbers (units) represent a low-level (high-level) construal of quantities, we show this reversal when mind-set shifts from concrete to abstract (studies 2–4). These results emerge for several quantities—height of buildings, time of maturity of financial instruments, weight of nutrients, and length of tables—and have significant implications for theory and practice.