Wednesday, January 23, 2013

Accuracy And Distortion Of Memory

One of the most controversial issues in the study of memory is the accuracy of recollections, especially over long periods of time. We would like to believe that our cherished memories of childhood and other periods in our life are faithful renditions of the past. However, several case studies and many experiments show that memories even when held with confidence can be quite erroneous.

The Swiss psychologist Jean Piaget reported a striking case from his own past. He had a firm memory from early childhood of his nurse fending off an attempted kidnapping, with himself as the potential victim. He remembered his nanny pushing him in his carriage when a man came up and tried to kidnap him. He had a detailed memory of the man, of the location of the event, of scratches that his nanny received when she fended off the villain, and finally, of a police officer coming to the rescue. However, when Piaget was 15 years old, his nanny decided to confess her past sins. One of these was that she had made up the entire kidnapping story to attract sympathy and scratched herself to make it seem real. The events Piaget so vividly remembered from his childhood had never actually occurred! Piaget concluded that the false memory was probably implanted by the nanny’s frequent retelling of the original story over the years. Eventually, the scene became rooted in Piaget’s memory as an actual event.

Tip of the Tongue State

Another curious phenomenon is the tip-of-the-tongue state. This term refers to the situation in which a person tries to retrieve a relatively familiar word, name, or fact, but cannot quite do so. Although the missing item seems almost within grasp, its retrieval eludes the person for some time. The feeling has been described as like being on the brink of a sneeze. Most people regard the tip-of-the-tongue state as mildly unpleasant and its eventual resolution, if and when it comes, as a relief. Studies have shown that older adults are more prone to the tip-of-the-tongue phenomenon than are younger adults, although people of all ages report the experience.

Often when a person cannot retrieve the correct bit of information, some other wrong item intrudes into one’s thoughts. For example, in trying to remember the name of a short, slobbering breed of dog with long ears and a sad face, a person might repeatedly retrieve beagle but know that it is not the right answer. Eventually the person might recover the sought-after name, basset hound.

One theory of the tip-of-the tongue state is that the intruding item essentially clogs the retrieval mechanism and prevents retrieval of the correct item. That is, the person cannot think of basset hound because beagle gets in the way and blocks retrieval of the correct name. Another idea is that the phenomenon occurs when a person has only partial information that is simply insufficient to retrieve the correct item, so the failure is one of activation of the target item (basset hound in this example). Both the partial activation theory and the blocking theory could be partly correct in explaining the tip-of-the-tongue phenomenon.

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