Among economists, it is an axiom that choice is good and more choice is better. Giving buyers more choice means more―and more intense―competition, which lowers prices, raises quality and fosters innovation. In the end, workers are more productive, consumers are better off and the economy is bigger and more efficient. 　Yes, up to a point, choice does enhance efficiency and consumer welfare. But at some point, there get to be so many options about what to buy or what career to go into or which mutual fund to invest in that many people make worse decisions than they would if they had fewer choices - or simply put off making a decision at all.    　All this is laid out in wonderfully readable form by Swarthmore College professor Barry Schwartz in his recent book, “ Why More Is Less.” Schwartz conducted an experiment in which he offered $1-off coupons to customers who sampled a new line of jams and jellies. In one test, consumers could taste only six of the 24 varieties; in a second, all 24 varieties were made available. While 30 percent of those exposed to the smaller sample bought a jar, only 3 percent of those who sampled from the complete line did so.   　You might have a reasoning like the next. If people are puzzled by having 12 choices rather than two, they could ignore the extra 10 and be just as well off. But people aren't rational, and they can't force themselves to ignore choices once presented. Now you’ve realized why it is that people in the United States don't report themselves any happier than people in Poland. Paradoxically more can be less.