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Confusion, Not Decay, Drives Forgetting Over Short Term

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Even though forgetting is such a common occurrence, scientists have not reached a consensus as to how it happens. One theory is that information simply decays from our memory—we forget things because too much time has passed. Another idea states that forgetfulness occurs when we confuse an item with other items that we have previously encountered (also known as temporal confusability). The illustration below does not contratict either of the two mechanisms.

The  Curve of Forgetting describes how we retain or forget information that we learn/memorize. This example is based on memorizing that occurs during a one-hour lecture.  (from the University of Waterloo, Counselling Services)

The Curve of Forgetting describes how we retain or forget information that we learn/memorize. This example is based on memorizing that occurs during a one-hour lecture. (from the University of Waterloo, Counselling Services)

It appears though, that uniqueness of an information compared to its embedding background is more important for its successful memorizing than its iteration over a period of time. (Of course a repeated information within a lecture stands out by its repetitiveness as well, whence the confusion…) Psychologists Nash Unsworth from the University of Georgia, Richard P. Heitz from Vanderbilt University and Nathan A. Parks from the Georgia Institute of Technology investigated the two theories to pinpoint the main cause of forgetfulness over the short term. In their study, the participants were presented with a “Ready” screen (on a computer) for either 1.5 seconds or 60 seconds. Following this, they were presented with a string of three letters and were instructed to remember them for a later test. But, before they were asked to recall the three letters, the volunteers were told to count backwards for various amounts of time (4, 8, 12 or 16 seconds).

The results, reported in Psychological Science, a journal of the Association for Psychological Science, reveal that temporal confusability, and not decay, is important for forgetting over the short term. The volunteers who had to count backwards for the longest amount of time were better able to recall the letters than volunteers who were asked to count backwards for a shorter time period. If decay was the culprit behind forgetting, the group that was asked to count backwards for a longer amount of time would have performed the worst during recall.

The authors conclude that “it is possible to alleviate and even reverse the classic pattern of forgetting by making information distinct, so that it stands out relative to its background”. These findings have very important implications not just for everyday memory use, but also for educational practices and for populations with memory problems, such as the elderly.

Psychological Science, 2008; 19 (11): 1078 DOI: 10.1111/j.1467-9280.2008.02203.x
The Importance of Temporal Distinctiveness for Forgetting Over the Short Term.
Nash Unsworth, Richard P. Heitz, and Nathan A. Parks

ABSTRACT—Rapidly forgetting information once attention is diverted seems to be a ubiquitous phenomenon. The cause of this rapid decline has been debated for decades; some researchers claim that memory traces decay as a function of time out of the focus of attention, whereas others claim that prior memory traces cause confusability by interfering with the current trace. Here we demonstrate that performance after a long delay can be better than performance after a short delay if the temporal confusability between the current item and previous items is reduced. These results provide strong evidence for the importance of temporal confusability, rather than decay, as the cause of forgetting over the short term.

Written by huehueteotl

December 15, 2008 at 11:24 pm

Posted in Psychology

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