Bavelier's graduate student, Mrim Boutla, was investigating visual memory and wanted to know more about American Sign Language and decided to test this view. The team devised studies to put sign language tests on equal footing with hearing-designed tests. To their surprise they found that even when signs were faster to pronounce than spoken language, signers recalled only five items. Even more surprising, when the team tested hearing individuals who were fluent in American Sign Language, such as people who had grown up with deaf siblings or parents, they found that the same people scored differently when asked to recall spoken lists in order, versus when they recalled signed lists. The discrepancy broke down as expected: seven heard items remembered, five signed items remembered. It was obvious that the regular ordered-item tests were not accurately evaluating the cognitive ability of deaf individuals in relation to those who could hear.

Up until this time, the predominant idea was that the magic number of seven was a good measure of overall cognitive capacity, likely utilizing the centers of the brain for memory and language. No one thought that perhaps a test for one kind of language might not work well for another language like sign language--researchers had always assumed the tests were evaluating the same cognitive aspects of the brain, whether spoken or signed.

In a direct evaluation of the memory test itself, Bavelier designed an experiment that would test more directly the memory centers of the brain for language, without favoring auditory or visual processing. Instead of asking her subjects to recall the order of a list, a task at which the auditory brain is superior, Bavelier concentrated on devising a test that required recall, but not in the temporal order of the items. Both hearing and deaf subjects were given a list of words like "boat" and "table" and aske
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Contact: Jonathan Sherwood
jonathan.sherwood@rochester.edu
585-273-4726
University of Rochester
31-Aug-2004