The Psychology of Choice Formats: The Case of Quantity Integration

In everyday life, people often must decide not only whether to do something, but also the quantity or magnitude of that action. Athletes consider not only whether to run, but for how long; shoppers consider not only whether to buy toilet paper, but also the number of rolls; individuals consider not only whether to contribute to retirement savings, but also how much to contribute. This research explores how the choice structure of these action and quantity decisions influences people’s likelihood of acting. In 30+ lab studies and a field experiment with HP.com, I find that integrating the action and quantity decisions into a single choice (vs. resolving them sequentially) substantially increases the likelihood of purchasing. I document a similar effect with opting-in to financial programs, using a field experiment conducted with Mint.com and nine lab studies. Finally, I explore how quantity integration can be harnessed for healthful behaviors, such as getting users to agree to—and actually follow through on—practicing guided meditations. I will unpack the psychological mechanisms underlying this effect and, more broadly, discuss how this work sheds light on the psychology of choice formats.