One reason is that producers face an apparently entrenched perception, fed by comparative shopping, that some of their wines are overpriced.

"I didn't think of doing any comparative shopping," said Dr. Leid.

By the time I finished comparative shopping $10 wood jewelry boxes, Aziz was rolling his eyes.

Both the original process (to buy a computer) and the comparative shopping are reason-driven.

Travelers were being offered a blizzard of discounts that made comparative shopping nearly impossible.

However, if the house is priced fairly, and this soon becomes apparent from comparative shopping, the buyer may eventually improve the offer substantially.

Learning time extends to trips to the supermarket and toy store for comparative shopping, and to other real-world activities.

The culture of recordings has already turned us away from discovery and toward comparative shopping.

Mr. Glinka said he could not blame customers for comparative shopping.

"They're actually taking the time to do comparative shopping," Mr. Shannon said.