As you all no doubt know, given the extensive national and international coverage of this tragic case, there was an eye-witness report from a graduate student who testified to a grand jury that he witnessed what he judged to be a likely sexual assault of a young boy by former Penn State assistant football coach Jerry Sandusky in a Penn State locker room shower in 2002.
Reportedly, the Board of Trustees was informed that three previous grand juries investigating earlier allegations against Jerry Sandusky were inconclusive. As we do not have access to those grand jury deliberations, we can only speculate that a/the difference for this fourth grand jury was the eye-witness testimony of the graduate student. The grad student also reportedly told school administrators what he saw, and they also testified to the grand jury. Jerry Sandusky was indicted by the fourth grand jury in November 2011.
From what we know of cognitive neuroscience, how likely is it that the grad student's memory, (or that of Jerry Sandusky, or the Penn State administration or Board of Trustees), is now accurate as to what they really did, saw or heard? Is their personal memory of the events now the same as it was 10 years ago in 2002?
As previous editions of this blog have described, the ability of eye-witnesses to accurately describe even major details of traumatic events is extremely poor. A large number of research studies done after the death of Lady Di ("The Death of Princess Diana: The Effects on Memory Enhancement Procedures on Flashbulb Memories" in Imagination, Cognition and Personality, Vol 25,3, 2005-2006 by Krakow, E, et.al.) and 9/11 demonstrated conclusively that the accuracy of our memories degrades rapidly, whether the memories are traumatic or mundane. Traumatic events have the additional problem of focusing on one particularly emotional element to the virtual exclusion of items of perceived lesser importance.
Post 9/11, a large national study was conducted on 9/11 memories with more than 3000 folk in 7 cities by a group of scientists called the Memory Consortium. Surprisingly, a year later, only about 2/3 of their memories were the same as their initial memories. After three years, only about 1/2 of their memories were the same.
Talarico, J.M. and Rubin, D.C. in "Confidence Not Consistency Characterizes Flashbulb Memories" in Psychological Science, 14, 2003, interviewed 54 students on their memories of 9/11 on 9/12 as well as one week, six weeks or 32 weeks later with the same questions. Their memories of 9/11 were surprisingly no more accurate than their memories of simple mundane occurrences over the same period.
For both traumatic and mundane situations, consistent details decreased by 1/3 in 8 months, with more inconsistencies. However, the students were much more confident in the accuracy of their traumatic 9/11 memories. One of the big surprises was that their memory of how they felt emotionally at their time was particularly inaccurate. The emotional state they remembered was dictated by their CURRENT emotional situation. One year later, only 42% described their original emotional state correctly.
As you may recall from an earlier blog, what we remember is largely controlled by how emotional we were about an event when it occurred. When we look at a series of pictures, those which trigger an emotional response are much more likely to be remembered than those which don't. When we remember something, it doesn't go precisely to one location like a hard drive, but is instead sent "all over the place" in the brain.
When emotions are involved, the amygdala assures that those are noticed, and the hippocampus, the hub of memory formation, encodes, stores, consolidates and dispatches pieces of the memory to various regions like the auditory, parietal and visual cortex, for sound, movement and sights, respectively, as was discussed in an earlier blog. The role of the amygdala in orchestrating the memory-boosting effects of emotion was demonstrated over the last 15 years by many neuroscientists including LeDoux, LaBar, Spencer, McGaugh.
What the brain does in recalling a memory is go to that portion of the appropriate cortex. If the memory is "falling down the stairs", it will bring back that particular incident, but it will also likely bring back parts of other memories of other incidents of "falling down the stairs" and put them with the original memory being recalled. The brain has been Darwinianly constructed in this way in the interest of survival. It is more important for the brain to bring back all it can find related to this problem so that you can be protected if a similar future event arises. Whether it is a perfectly accurate record of a particular event is not really important for ultimate survival.
This phenomena was described in an earlier blog on "misinformation" studies in an effect called "retrieval-enhanced suggestibility". Much research on this has been done including work @ Iowa State by Jason Chan published in the Journal of Experimental Psychology: Learning, Memory and Cognition” in January 2011. This approach of modifying a memory has been used by interrogators, and attorneys, to construct a "new" memory of an event with specific elements inserted or deleted, as benefits their cause.
The more times a memory is recalled, and the more intense, and emotion-packed those recalling situations are, the more likely the memory is to be changed. There is also the tendency for cognitive dissonance, which is the tendency for a person to engage in self justification after a decision. Given the extreme media pressure on all of the key figures in this case, the number of times and venues in which they have already had to recall that event, and the fact that 10 years have passed, it would appear to be very difficult for the story that actually now unfolds, even given the very best efforts of all those involved at accurately reporting it, to be what actually transpired in 2002.
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