I've got an article in the Boston Globe Ideas section on a phenomenon that's always fascinated me: the tip-of-the-tongue moment.
Late in 1988, a 41-year-old Italian hardware clerk arrived in his doctor's office with a bizarre complaint. Although he could recognize people, and remember all sorts of information about them, he had no idea what to call them. He'd lost the ability to remember any personal name, even the names of close friends and family members. He was forced to refer to his wife as "wife."A few months before, the man, known as LS in the scientific literature, had been in a serious accident. He was thrown from his horse and the left side of his skull took the brunt of the impact. At first, it seemed as if the man had been lucky. A battery of routine tests had failed to detect any abnormalities. But now he appeared stuck with this peculiar form of amnesia, so that the names of people were perpetually on the tip of his tongue. It was agonizing.
The paradox, of course, is how we know what we don't know. If we've forgotten a person's name, then why are we so convinced that we remember it? What does it mean to know something without being able to access it?






Comments (12)
My initial thoughts would be that a situation like this would be either some sort complete disruption of a specific and isolated pathway. In that case, information that normally travels to several parts of the brain simultaneously (such as to other premotor and frontal cortex areas as well as to the motor cortex or cranial nerves for speech) might, in the case of tip-of-the-tongue situations, be going only to the premotor and higher reasoning areas without going to the corresponding "action" areas. Hence the person experiences the feeling of know that they should be saying something, but for some reason simply cannot.
Of course, that was just an initial thought, and during the course of writing it I realised there are all sorts of problems with it. For one, that model really wouldn't really give much explanation for why such a situation could happen to a healthy brain. Anyway, that is part of why I enjoy neuroscience... I can end up debating myself over some idle thought when I really ought to be doing work.
Posted by: Mozglubov | June 2, 2008 10:43 AM