The implications of this elegant experiment are far reaching. "Let's suppose:' postulates McGaugh, "that a plane crashes near Pittsburgh and you're hired to pick out the body parts. If we give you a beta blocker, we impair your 'emotional' memory, the memory for the trauma, without impairing your normal memory."
Pittman looks forward in the next decade to drugs that not only block PTSD but help ameliorate it. "There seems to be a window of opportunity, up to six hours or so in rats in any case, before memories are consolidated." During that time effective drugs, such as beta blockers, might be administered.
MEMORY LOST AND REGAINED
The stories are legendary. Elizabeth Loftus has found ordinary memory to be so malleable that she can prompt volunteers to "remember nonexistent broken glass and tape recorders; to think of a clean-shaven man as having a mustache, of straight hair as curly, of hammers as screwdrivers, to place a barn in a bucolic scene that contained no buildings at all, to believe in characters who never existed and events that never happened."
Sometimes the memories become so seemingly fantastical that they lead to court cases and ruined lives. "I testified in a case recently in a small town in the state of Washington," Loftus recalls, "where the memories went from, 'Daddy made me play with his penis in the shower' to 'Daddy made me stick my fist up the anus of a horse,' and they were bringing in a veterinarian to talk about just what a horse would do in that circumstance. The father is ill and will be spending dose to $100,000 to defend himself."
Nobody is quite sure how memories might be lost to us and then later retrieved--so-called repression. Whatever it is, it is a different process than traumatic amnesia, a well-known phenomenon where a particular horrendous event is forgotten because it was never consolidated in long-term memory in the first place. Such is the amnesia of an accident victim who loses consciousness after injury. Repressed memory, on the other hand, is alleged to involve repeated traumas.
According to UCLA's Daniel Siegel, both amnesia and repression may be due to a malfunction of the hippocampus. In order to recall an explicit memory, and to be able to depict it in words and pictures, the hippocampus must process it first. Perhaps, postulates Siegel, the work of the hippocampus is disrupted during trauma-while other components of memory carry on. We know, for example, that primitive responses like fear or excitement stimulate the amygdala directly; learning can occur without our "knowing" it.
If explicit memory is impaired--you forget what happened to you--but implicit memory is intact, you may still be profoundly influenced by an experience. Siegel thinks that some individuals remove conscious attention during repeated trauma, say from an unbearable event like repeated rapes. In the parlance of the mind trade, they "dissociate."
While his theory may explain repressed memory plausibly, it doesn't suggest how the memory emerges decades later, explicit and intrusive. And it doesn't answer the contention of many researchers that such repression is probably rare, and that the wave of repressed memories we are hearing about today may be due to invention.
It turns out that it's relatively easy to confuse imagery with perception. The work of Stephen Kossyln, Ph.D., a psychologist at Harvard University and author of Image and Brain (MIF Press), has shown that the exact same centers in the brain are activated by both imagination and perception. "PET studies. have shown that, when subjects close their eyes and form visual images, the same areas are activated as if they were actually seeing." The strength of the imagined "signal" (or image) is about half that of a real one. Other research shows that the source of a memory--the time, place, or way the memory began--is the first part to fade. After all, the source of a memory is fragile.
If we concentrate on generating images that then get recorded in the web of neurons as if they were real, we might actually convince ourselves that confabulations are true. (This might also explain how some individuals who lie about an event eventually convince themselves, through repeated lying, that the lie is true.)
The fragility of source memory explains why, in a famous experiment by psychologist John Neisser, John Dean's testimony about Richard Nixon was shown to be both incredibly accurate and hugely inaccurate. "His initial testimony was so impressive that people called him a human tape recorder," recalls psychologist Charles Thompson, Ph.D. "Neisser then compared the actual tapes to his testimony, and found that if you really looked at the specifics, who said what and when, Dean was wrong all over the place. But if you just looked at his general sense of what was going on in the meetings he was right on target. His confusion was about the source." In general, supposes Thompson, this is how memory works. We have an accurate sense of the core truth of an event, Out we can easily get the details wrong.
"Memory is more reconstructive than reproductive. As time passes, details are lost. We did a study where we asked people to keep a daily diary for up to a year and a half, and later asked them questions about recorded events. The memory of the core event and its content stayed at a high level of about 70 percent, while the peripheral details dropped quickly."
CAN MEMORY CREATE THE SELF?
Tags:
aunt pearl,
credulity,
face down,
false memories,
malleability,
metaphors,
nightgown,
police cars,
repressed memory,
research psychologist,
revelation,
sense of self,
sense of wonder,
skeptical mind,
st martin
