In other words, he said, how much are people affected by the number of choices and “how much from the lack of information or any prior understanding of the options?”

I know this from experience. A while back, I spent a great deal of time trying to decide which company should provide our Internet, phone and television cable service. I was looking at only two alternatives, but the options — cost, length of contract, present and future discounts, quality of service — made the decision inordinately difficult.

This was not only because I wanted to get the best deal, but because the information from the companies was overly complicated and vague. I suspected that both companies were less interested in my welfare than in getting my money — and I didn’t want to be a sucker. This was a problem partly of choice overload — too many options — but also of poor information.

Research also shows that an excess of choices often leads us to be less, not more, satisfied once we actually decide. There’s often that nagging feeling we could have done better.

Understanding how we choose could guide employers and policy makers in helping us make better decisions. For example, most of us know that it’s a wise decision to save in a 401(k). But studies have shown that if more fund options are offered, fewer people participate. And the highest participation rates are among those employees who are automatically enrolled in their company’s 401(k)’s unless they actively choose not to.

This is a case where offering a default option of opting in, rather than opting out (as many have suggested with organ donations as well) doesn’t take away choice but guides us to make better ones, according to Richard H. Thaler, an economics professor at the Booth School of Business at the University of Chicago, and Cass R. Sunstein, a professor at Chicago’s law school, who are the authors of “Nudge: Improving Decisions About Health, Wealth and Happiness” (Yale University Press, 2008). Making choices can be most difficult in the area of health. While we don’t want to go back to the days when doctors unilaterally determined what was best, there may be ways of changing policy so that families are not forced to make unbearable choices.

Professor Iyengar and some colleagues compared how American and French families coped after making the heart-wrenching decision to withdraw life-sustaining treatment from an infant. In the United States, parents must make the decision to end the treatment, while in France, the doctors decide, unless explicitly challenged by the parents.