Standard theory holds that adding an option cannot make a chooser worse off.
If the new option is , it is simply ignored.
Experiments in the nineteen-nineties suggested otherwise and became famous faster than they were replicated.
A display of twenty-four varieties attracted more attention than a display of six and produced fewer purchases.
since have found the effect to be real, small and highly .
It appears when the chooser has no prior preference, when the options are hard to compare and when the decision feels .
Those three conditions describe pension choices, insurance policies and university courses precisely.
They do not describe a supermarket shelf, where a shopper has a habit and the cost of error is trivial.
The policy conclusion drawn from the early work was frequently wrong in an instructive way.
Reducing the number of pension funds available does not help a person who cannot compare two.
Making the options does, and the two interventions are frequently confused.
A single summary, with the same four numbers in the same order, transforms the decision without removing anything.
remain the most powerful instrument and the most politically sensitive.
A well-chosen default serves the person who does not choose, who is usually the person with least time and least information.
A badly chosen default does the same thing in the opposite direction and is never described as a choice.
Who sets the default is therefore the question that matters, and it is usually settled administratively.
The literature has moved on, and the popular version has not.
An finding survives in public discussion long after the field has qualified it, because the simple version is the one that can be repeated at a conference.