Frontier: The More You Know, the Sooner You Know It


by Elizabeth Norton Lasley

May, 2007

Knowledge comes more easily when it relates to what we know. Researchers based in Scotland have found that rats already trained to find food pellets learned more quickly when new flavors were added later.

In a study published in the April 6 issue of Science, Richard Morris of the University of Edinburgh and colleagues trained rats to find food pellets buried in wells of sand. The rats were given six weeks of training to remember the locations of six different flavors.

Subsequently, the animals found two new flavors after a single trial and remembered these locations for two weeks. In a previous study with less intensive training, the animals’ memories lasted less than 24 hours.

Psychologists believe that we learn by using “schemas,” or mental frameworks to which new information is applied. The quick learning that followed extensive training suggests that schemas develop in the brain, says Larry Squire of the University of California, San Diego: “We learn new information rapidly if we can hook it onto something we already know about, whereas the arbitrary is often forgettable.”

Removing the hippocampus three hours after the rats learned the location of two new flavors prevented memory formation—but removing it 48 hours later did not. This result suggests that the hippocampus does not permanently store the brain’s “maps” but guides the interconnections that form among other sites to consolidate many types of memory. Most important, says Squire, the new study suggests that the hippocampus does its job much more quickly than previously thought.