Politicians have famously poor memories for their mistakes and misdeeds. During Reagan's presidency, testified that he could not remember any involvement in the Iran-Contra affair. President Clinton frequently claimed that could not remember information when deposed about the Paula Jones case. More recently, Lewis "Scooter" Libby testified in court that he could not remember revealing the identity of CIA agent Valerie Plame to a reporter.
Our natural reaction to these memory lapses is utter disbelief. How could anyone not remember crucial information about an important situation? We don't have mind-reading machines, and so claiming faulty memory is a good defense. And undoubtedly a number of people accused of wrongdoing have lied about what they can and can't remember.
But there are some interesting psychology questions here. We know that people remember information from events that are important to them. We remember weddings, funerals and public tragedies (like 9/11). For these events, though, it is clear that they are important at the time that they happen.
The situations in which people might be called to testify in court have a somewhat different character. At least in some cases, it may not have been have been clear in advance that the event was going to become important later. I am sure that Presidents get briefings about issues all the time and cannot necessarily remember every detail about each issue years later.
So, one question is whether people are as good at remembering information they find out later to be important as they are at remembering information they know to be important to begin with. The other question is whether most people believe that people are good at remembering important information whether they knew it was important at the time they encountered it or not.
This issue was addressed in a paper by Karim Kassam, Dan Gilbert, Jillian Swencionis, and Tim Wilson in the May, 2009 issue of Psychological Science. They gave people facts to remember about a fictitious people. One group of people was told that they would get 10 cents for each fact they remembered, but when they heard about a particular woman, they would get 50 cents for each fact remembered about her. A second group heard all of the same facts, but they were not told about the bonus until after they studied. A third group had no bonus.
The people who were told in advance that some facts would be worth more money remembered more of those valuable facts than the people who had no bonus. The people who didn't find out about the bonus until after they studied did not remember the facts that well. They were about at the level of the people who had no bonus at all.
A particularly interesting aspect of this study, though, was that another group of people had the study described to them, and were asked to rate how many of the facts about the bonus person people would recall. These judges correctly realized that someone told about the bonus would remember far more facts than someone who was not told about the bonus. However, they mistakenly thought that people who found out about the bonus after hearing the facts would also remember many of them.
So, people overestimate how likely someone else will remember something that doesn't become important until after it happens. This result is important, because juries are often in the position of having to judge whether a defendant truly could not remember something. And these results suggest juries may make errors in their guesses about what people will be able to remember.
Of course, this does not mean that all politicians who claim a faulty memory are telling the truth. But at least it should make us think a bit before we judge too harshly.
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