Alzheimer’s: when you don’t know that you know…
They showed 23 patients 80 photos of famous individuals and 80 photos of unknown individuals on a computer screen. They took care to ensure that the two samples matched each other in terms of age, gender, and ethnic origin, etc. With regard to the famous individuals, the psychologists conducted a pre-test on normal elderly individuals to ensure that the celebrities in question were very well-known. Alain Delon, for example. For the unknown individuals, a learning stage was required. The objective of the first step was to enable the patients to become familiar with the faces of the different individuals shown on the screen. “We showed the faces and then we asked the participants to indicate whether it was a man or a woman”, explains Sarah Genon. “We then began the stage of encoding the information in memory by giving the name of the person (Caroline Martin, for example) and in order to create an association between the face and the name in the patient’s memory, we asked questions such as "Do you think Caroline Martin is aptly named?”, and why”? Finally, we hid the name of the person on the computer screen where the photos appeared and asked the patient to recall the name of the person immediately. In the case of a correct answer, we considered that the information was encoded and moved on to the next item; in the case of failure to provide a correct answer, we started the process again”. FailureWith regard to metacognition concerning episodic memory (fictional people), it emerged that, in relation to the group of elderly people unaffected by Alzheimer’s (a sample of 17 volunteers), the Alzheimer’s patients were more prone to pessimistic predictions (i.e. indicate low likelihood) of their ability to recognize the name, which they would in fact correctly identify a short time later – in a manner of speaking, they didn’t know that they knew. On the other hand, when metacognition concerned semantic memory (famous people), the patients knew that they had a good chance of recognizing the person. “They judged their semantic memory performance in a similar way to normal elderly individuals”, explains Sarah Genon. |
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© 2007 ULi�ge
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