Some amnesiacs can remember things they're told for several seconds, but if you ask them again in a minute, they've already forgotten. In this study of amnesia patients, researchers looked at what it is that interferes with the memories.

What the researchers wanted to know: Do amnesiacs forget memories because of distractions between the time the memory is created and the time they're asked to recall it?

What they did: The researchers were inspired by a classic study on cockroaches in the 1940s, which showed that making the bugs rest after an electric shock shortened the amount of time it took to train them. The conditions were a little better for the six amnesia patients and six controls in this study. Each was read a list of 15 unrelated Italian nouns (the participants were Italian). Ten minutes later, each was asked to repeat the words in any order. During the 10-minute gap, each participant either lay quietly in a darkened room or took a series of psychometric tests to distract him or her. In a second test, a participant was read a story, had a one-hour delay of tests or rest, and repeated the story as well as possible. Both tests were carried out multiple times for each patient.

What they found: Patients remembered more if they were allowed to rest before being asked to remember the words or stories. For example, three of the amnesiac patients remembered nothing about the story after being distracted for an hour—but remembered between 63 and 85 percent after a rest. Resting helped the controls, too, but not as much, since they didn't have the same problems to start with. Amnesia patients also remembered more of the word list in the experiment with the 10-minute rest.

What the study means to you: People with amnesia might be able to use this technique to improve their memories. Research like this on amnesia helps scientists understand the condition and may help separate different kinds of amnesia; for example, two patients who had lesions in the same part of the brain, the temporal lobe, couldn't remember even after a rest.

Caveats: This is quite a small study, but it's still interesting.

Find out more: This unit on memory from a psychology class at San Francisco State University includes a description of the cockroach experiment.

A collection of links on memory from the National Library of Medicine

Read the article: Cowan, N., Beschin, N., and S. Della Sala. "Verbal Recall in Amnesiacs Under Conditions of Diminished Retroactive Interference." Brain. April 2004, Vol. 127, No. 4, pp. 825–834.

Abstract online: http://brain.oupjournals.org