The scientists, led by  Betsy Sparrow, an assistant professor of psychology at Columbia, wondered whether  people were more likely to remember information that could be easily retrieved from a computer, just as students are more likely to recall facts they believe will be on a test.

Dr. Sparrow and her collaborators, Daniel M. Wegner of Harvard and Jenny Liu of the University of Wisconsin, Madison, staged four different memoryexperiments. In one, participants typed 40 bits of trivia — for example, “an ostrich’s eye is bigger than its brain” — into a computer. Half of the subjects believed the information would be saved in the computer; the other half believed the items they typed would be erased.

The subjects were significantly more likely to remember information if they thought they would not be able to find it later. “Participants did not make the effort to remember when they thought they could later look up the trivia statement they had read,” the authors write.

A second experiment was aimed at determining whether computer accessibility affects precisely what we remember. “If asked the question whether there are any countries with only one color in their flag, for example,” the researchers wrote, “do we think about flags — or immediately think to go online to find out?”

In this case, participants were asked to remember both the trivia statement itself and which of five computer folders it was saved in. The researchers were surprised to find that people seemed better able to recall the folder.

“That kind of blew my mind,” Dr. Sparrow said in an interview.

The experiment explores an aspect of what is known as transactive memory — the notion that we rely on our family, friends and co-workers as well as reference material to store information for us.

“I love watching baseball,” Dr. Sparrow said. “But I know my husband knows baseball facts, so when I want to know something I ask him, and I don’t bother to remember it.”

The Internet’s effects on memory are still largely unexplored, Dr. Sparrow said, adding that her experiments had led her to conclude that the Internet has become our primary external storage system.

“Human memory,” she said, “is adapting to new communications technology.”