by Sheena S. Iyengar and Mark R. Lepper
Journal of Personality and Social Psychology,
Vol. 79, # 6, 2000, pp. 995-1006.
Hypothesis accepted: The number of options displayed affects consumers' initial attraction to or subsequent purchase of the displayed product.
Experiment supporting hypothesis
Location: Dreager's Grocery Store in Menlo Park, California
Groups:
- Experimental group #1: taste testing booth offering 6 jars of Wilken & Sims (Purveyors to Her Majesty the Queen) gourmet jams costing between $4 and $6. This is called the "limited-choice option."
- Experimental group #1: taste testing booth offering 24 jars of Wilken & Sims (Purveyors to Her Majesty the Queen) gourmet jams costing between $4 and $6. This is called the "extensive-choice option."
- No control group
- On two Saturdays, taste testing booth was set up for five hours in Dreager's Grocery Store.
- The 6-jar and 24-jar booth was switched each hour.
- Everyone approaching booth was encouraged to taste as many jams as they wished.
- Everyone was given a dollar-off coupon for purchasing a Wilkins & Sons jam to be selected from regular shelves containing 28 jams.
Even though the 24-jar booth attracted 20% more people than the 6-jar booth, about the same number of jams were actually tasted and, amazingly, the 6-jar booth sold 7 times more jars of jam. The researchers explained, "... an extensive array of options can at first seem highly appealing to consumers, yet can reduce their subsequent motivation to purchase the product."
This paper reports on two more experiments.
- Experiment two showed that students were more likely to write an extra credit paper and write a better paper when choosing from a list of 6 rather than 30 topics.
- Experiment three revealed that people claimed to enjoy more selecting from a display of 30 chocolates than a display of 6 topics. However, those selecting from a display of 30 chocolates were also more likely to be dissatisfied, regret their choice and, when given a choice of $5 or a box of chocolate worth $5, to choose the chocolate.
Application to libraries:
- One major difference between this study and selecting books in a library is that this study asked people to spend $3 to $4 for a jar of jam. Library books are free. This difference may undermine the application of this study to library situations.
- Nevertheless, this study suggests that library book displays may have an optimal size that would circulate more library books than displays larger and smaller. That optimal size would be the balance point between large enough to attracting patrons, but small enough to encourage people to pick.
- Maybe the best display would be a large display composed of smaller displays on a variety of topics. The large size would be easily seen at a distance and draw people to the display. When people reached the display, they would see many small displays on a wide-variety of topics. The small size of each display would make selection easy and quick.
- Bibliographies do not have to be comprehensive. A short list of selected titles will do.