Memory's Seven Sins

Schacter's Seven Sins of Memory

Notes on Daniel L. Schacter (1999) "The Seven Sins of Memory: Insights From Psychology and Cognitive Neuroscience" (Full text) American Psychologist Vol. 54. No. 3, 182-203

This is a 22-page review paper that summarises seven ways in which human memory can fail, and argues that despite the problems they cause, they are all side-effects of positive features of memory. In other words, if we could get rid of these forgetting and biasing processes, we would actuallly be worse off as our minds were flooded with irrelevant and confusing information. Schacter expanded this paper into a 2001 book.

My own interest is in bias, rather than in the biological basis for memory or the relation between the different memory systems. This paper is useful for students of bias firstly because it sets out ways in which memory can be biased, and secondly because it illustrates how some human irrationality can be explained as adaptive. In the notes below I've made use of a couple of Schacter's other papers which are cited.

The Seven Sins

"The first 3 sins involve different types of forgetting, the next 3 refer to different types of distortions, and the final sin concerns intrusive recollections that are difficult to forget." - from the abstract.

Transience

This is straightforward forgetting: the decay of recalled information over time. The brain has multiple memory systems, with different forgetting characteristics.

Absent-mindedness

"[I]ncidents of forgetting associated with lapses of attention during encoding or

during attempted retrieval can be described as errors of absent-mindedness"

Blocking

"When people are provided with cues that are related to a sought-after item, but are nonetheless unable to elicit it, a retrieval block has occurred", e.g. tip-of-the-tongue phenomenon

Misattribution

Schacter identifies three kinds of misattribution:

1. Source confusion: "people may remember correctly an item or fact from a past experience but misattribute the fact to an incorrect source" e.g. eyewitnesses confusing where or when they saw a particular person; subjects confusing whether they saw something in real life or on television; confusions between imagination and memory
2. Cryptomnesia: "an absence of any subjective experience of remembering. People sometimes misattribute a spontaneous thought or idea to their own imagination, when in fact they are retrieving it—without awareness of doing so—from a specific prior experience" e.g. unconscious plagiarism
3. False recall and false recognition: when individuals falsely recall or recognize items or events that never happened. In some experiments, subjects show just as much confidence in their false recall as in their correctly recalled items.

A paper in which Schacter goes into more detail on misattribution is D. L. Schacter and C. S. Dodson (2001) "Misattribution, false recognition and the sins of memory." (Full text PDF) Philosophical Transactions of the Royal Society of London Series B, Biological Sciences Sep 29;356(1413):1385-93.

Suggestibility

"Suggestibility in memory refers to the tendency to incorporate information provided by others, such as misleading questions, into one's own recollections". Suggestibility is really a kind of misattribution. Schacter uses the term "suggestibility" for misattribution where the misattributed information is suggested by another person. e.g. Loftus "lost in the mall" study. Repeated and/or specific questions can cause the subject to vividly imagine an event, and then they can misattribute this vivid mental image as a memory.

Bias

"Bias refers to the distorting influences of present knowlege, beliefs, and feelings on recollection of previous experiences" Bias is discussed briefly in the 1999 paper, but at greater length in Schacter's 2001 book.

• Consistency bias: memories of past attitudes distorted to be more similar to present attitudes. (including distortion of memory by cognitive dissonance)
• Change bias: people who have worked hard to improve their study skills distort their memory of how good they were before the course downwards (justification-of-effort bias?)
• Stereotypical bias: e.g. racial and gender biases in memory, e.g. made-up "black" names are more frequently falsely remembered as names of criminals than "white" names
• Hindsight bias: recollections of past events are filtered by current knowledge;
• Egocentric bias: individuals recall the past in a self-enhancing manner; e.g. fishermen "remembering" catching bigger and bigger fish.

A more recent paper about bias is Daniel L. Schacter, Joan Y. Chiao, Jason P. Mitchell (2003) "The Seven Sins of Memory. Implications for Self" (Full text, subscription required) Annals of the New York Academy of Sciences 1001 (1), 226–239.

Persistence

"Persistence involves remembering a fact or event that one would prefer to forget. Persistence is revealed by intrusive recollections of traumatic events, rumination over negative symptoms and events, and even by chronic fears and phobias." Depressed subjects show greater memory for negative events and stimuli (a persistance bias?).