Byline: August Gribbin
A Washington State University neuropsychologist has demonstrated there is a way for severely brain-damaged patients to learn even though their memories are impaired.
In a series of complex computer tests, Maureen Schmitter-Edgecombe and her assistant, Heather M. Nissley, showed that patients with severe closed-head injuries could identify, recall and then indicate where on their computer screen a given "target number" had been flashed.
The study indicates that persons who have survived serious head injuries are able to learn "without awareness," as one critique puts it. That finding raises hope for lessening the disability of certain cognitively disabled victims through innovative rehabilitation techniques.
Beyond that, the study, which appears in the scholarly journal Neuropsychology, contributes to the gathering evidence that implicit learning is facilitated by a separate neural mechanism in the brain than explicit learning. It's thought that the separate system that evolved early in man's development is comparatively unchanging and tends to be more resilient than the system used in explicit learning.
"I don't want to go beyond the data, but we demonstrated - in what we believe is a perceptual, implicit system - that the closed-head-injury patients learn just like normal people, although they are not aware they are learning," says Mrs. Schmitter-Edgecombe.
By "implicit system," Mrs. Schmitter-Edgecombe refers to a learning process like that used by young children who learn rules of grammar and piece together coherent sentences without having to be taught how - and without realizing they are learning. Implicit learning is contrasted with "explicit learning," the kind of purposeful attention and memorization used in school or on the job.
"The key for us now is to figure out how to utilize these unconscious mechanisms that don't involve a conscious learning route. We now know the potential for learning exists. We have to find out how to work with that knowledge," she says. …