5/22/2006

The Origins of Memory Distortion

In a series of posts last week, I have reconceptualized the “seven sins of memory” as a group of memory inaccuracies arising from just three types of system failure. To recap briefly:
  1. failures related to maintenance can explain rapid forgetting, prospective memory failures, and absent-mindedness (claim supported here).
  2. memory search failures can result in interference, levels-of-processing phenomena, infantile amnesia (claim supported here), as well as directed forgetting, tip-of-the-tongue phenomena, retrieval-induced forgetting, and consolidation-related forgetting (claim supported here).
  3. monitoring failures can explain false memory effects, consistency biases, source misattribution errors, and incorrect recall from the DRM paradigm (supported here).

I have described how each of these failures can cleanly account for much of the evidence used to support a classification scheme with seven categories (although it should be noted that I have not covered Schacter's sin of "persistence," which in truth is not really a memory failure anyway). However, the current classification scheme has a few additional benefits, as described below.

First, this framework is capable of accounting for memory phenomena not considered in Schacter’s original proposal. For example, I have described how infantile amnesia and interference in the AB-AC task can both result from failures of cue specification in the process of memory search.

Second, this framework can be extended to explain yet other memory inaccuracies as resulting from multiple failures. For example, déjà vu might be considered a failure of both maintenance and search, in which sufficiently precise cues are unavailable (which would otherwise elicit the original experience giving rise to the sensation of familiarity). However, déjà vu is also characterized by a simultaneous failure to maintain the item or characteristic of the current experience that originally triggered the sensation of familiarity.

Third, this framework is more parsimonious (by virtue of positing fewer constructs), and is much more compatible with the functional anatomy of memory than Schacter’s “seven sins.” For example, some evidence suggests that maintenance, cue specification, and monitoring may be implemented by distinct neural regions in prefrontal cortex (Dobbins et al., 2002). In contrast, it is almost unthinkable that concepts as abstract as bias or transience could be localized to a specific brain region.

In conclusion, Schacter’s “seven sins” did an admirable job of classifying memory inaccuracies in an intuitively appealing way. Further examination of these phenomena, however, has afforded the re-classification proposed above. This proposal is just as complete, while both more parsimonious and more compatible with an emerging view of the neuroanatomy supporting memory functions.

References:

Dobbins, I. G., Foley, H., Schacter, D. L., & Wagner, A. D. (2002). Executive control during episodic retrieval: Multiple prefrontal processes subserve source memory. Neuron, 35, 989-996.

2 Comments:

Anonymous Anonymous said...

I think you have written a great series but have found it very hard to follow unfortunately. So much so that I am not sure I can use it as a reference in the paper that I am writing; for lack of better words it is much too "wordy." Wishing there was a copy of this "for dummies"...

11/11/2006 02:31:00 PM  
Blogger Chris Chatham said...

Hi - I'm really sorry to hear that - this was written for one of my classes, originally, and the word count was restricted; if i had found a quicker way to say it, I would have!

Please let me know if you are having difficulty with anything in particular, or would like more clarification on anything. THe more specific your comments the more likely I will be able to address them, perhaps in a new post or maybe just in updates to these posts for clarification.

11/11/2006 02:37:00 PM  

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