Why Are Thirty Jams Worse Than Six? Too Many Options Stop People Choosing

Sheena Iyengar and Mark Lepper set up a tasting table in a Californian supermarket in a study published in 2000, alternating between a display of six jams and one of twenty four. The larger display attracted more people to stop, which was expected, and produced a dramatically lower rate of purchase among those who stopped, with a figure commonly reported as three per cent against thirty per cent. Related studies in the same paper found that students given a smaller set of essay topics were more likely to write one and produced better work. The result was memorable, counterintuitive and fitted a broader argument about abundance, and it became one of the most cited findings in consumer psychology.

Several mechanisms have been proposed and they are not mutually exclusive:

• •The effort of comparing rises sharply as options multiply
• •Every choice forgoes more alternatives, which increases anticipated regret
• •Trade-offs become explicit and unpleasant when many attributes differ
• •Confidence in having chosen well falls, which reduces satisfaction afterwards
• •Deferring the decision becomes the easiest available option
• •A person without clear preferences has nothing to narrow the field with

The finding has been examined closely and the picture is considerably more complicated than the original presentation. A meta-analysis published in 2010 combining fifty experiments found an overall effect of essentially zero, with large effects in some studies and effects in the opposite direction in others. Several direct replications of the jam study failed to reproduce it. What the analyses identified is a set of conditions under which the effect does appear, namely when the person has no prior preference, when the options are difficult to compare, when the decision is complex and when there is no clear way to narrow the field. Outside those conditions, more options generally help, which is what economic theory predicted all along.

The result travelled far beyond psychology and shaped decisions involving considerable sums. Retailers reduced ranges deliberately, with several large chains cutting the number of products on their shelves and reporting increased sales, though isolating the cause in a real business is nearly impossible. Pension providers reduced the number of funds offered after research indicated that participation in retirement schemes fell as options multiplied, which is among the more robust findings in the area since the decision is complex and most people have no prior preference. Menu design, software configuration and government service design all absorbed the lesson. The fact that the underlying effect turned out to be conditional rather than general has not much slowed its adoption as a design principle.

The practical lessons survive the statistical complications reasonably well. Narrowing a field before comparing in detail is more effective than comparing everything, and a rule that eliminates most options quickly, however arbitrary, does most of the work. Knowing what matters before looking prevents the options themselves from setting the criteria. Deciding in advance what would be good enough, and taking the first option meeting it, produces outcomes almost as good as exhaustive search with a fraction of the effort and considerably more satisfaction afterwards. And treating a decision as reversible where it genuinely is removes most of the weight from it, which is why return policies affect purchasing so strongly.

A supermarket study found a display of twenty four jams attracted more interest and produced far fewer purchases than one of six, and the result became enormously influential. A meta-analysis of fifty experiments found an overall effect of essentially zero, with the effect appearing where the person has no prior preference and the options are hard to compare. Narrowing before comparing and deciding what is good enough in advance both help.