Joseph Nunes

Who they are

Nunes works on consumer behaviour, and in particular on loyalty programmes and what keeps customers working towards a reward. The 2006 paper with Drèze is the work this site draws on, and its car wash card appears in popular books on habit and product design.

The finding often reaches readers without his name. Nir Eyal's Hooked, which uses the car wash card as an example in its chapter on action (pp. 89 to 90), describes the result as an 82 per cent higher completion rate. That figure is the relative difference between the two completion rates, and the researchers are named in the book's notes rather than its text. This site credits Nunes and Drèze by name and gives the two rates.

This page records only what the papers and their published records state. Biography beyond the cited work is not given here.

Key papers

The endowed progress effect: how artificial advancement increases effort (2006), with Xavier Drèze. In the field study at the heart of the paper, car wash customers received loyalty cards. One group got a blank card that needed eight stamps for a free wash. The other got a card that needed ten stamps but arrived with two already stamped, so both groups had eight washes to go. About 34 per cent of the customers with the head start completed their card, against 19 per cent of those with the blank card.

The paper's abstract reports that artificial advancement increases both persistence and completion, and that the effect is driven by a sense of how much of the task is already done, not by reluctance to waste credit already given. It also reports that the effect depends on the reason given for the head start and on the currency in which progress is counted.

Key ideas

The central idea is that people judge a goal by how far along they feel, not only by how much work is left. Two cards that require exactly the same number of purchases can produce different behaviour if one of them presents some of the distance as already covered.

The idea connects to older work on the goal gradient, the observation that effort rises as a reward gets closer. In a 2006 study in the Journal of Marketing Research, Ran Kivetz and colleagues found that café customers given a 12-stamp card with 2 bonus stamps completed their 10 required purchases in 12.7 days on average, against 15.6 days for customers with a plain 10-stamp card.

The evidence has limits. The car wash result comes from a single field experiment of modest size in one business, and it has not been repeated in a registered replication. The abstract's own moderators mean that a head start is not a fixed bonus: its effect depends on the reason customers are given for it and on what the progress is counted in. Later research on progress indicators in online surveys has found that whether a progress bar helps depends on how fast it appears to move.

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