The U.S. legal system has long assumed that all testimony is not equally credible, that some witnesses are more reliable than others. In tough cases with child witnesses, it assumes adult witnesses to be more reliable. But what if the legal system has had it wrong?
Valerie Reyna, a human development professor, and Chuck Brainerd, a human development and law school professor are both researching the topic at Cornell University. They believe, that like the two-headed Roman god Janus, memory is of two minds—that is, memories are captured and recorded separately and differently in two distinct parts of the mind.
They say children depend more heavily on a part of the mind that records, "what actually happened," while adults depend more on another part of the mind that records, "the meaning of what happened." As a result, they say, adults are more susceptible to false memories, which can be problematic in court cases.
Reyna's and Brainerd's research sparked more than 30 follow-up memory studies, which they review in an upcoming issue of the Psychological Bulletin. That research shows that meaning-based memories are largely responsible for false memories, especially in adult witnesses. Because the ability to extract meaning from experience develops slowly, children are less likely to produce those kinds of false memories than adults are, and more likely to give accurate testimony when properly questioned.
The finding is counterintuitive; it doesn't square with current legal tenets, and may have important implications for legal proceedings.
"Because children have fewer meaning-based experience records, they are less likely to form false memories," says Reyna. "But the law assumes children are more susceptible to false memories than adults."
The court's reliance on adult testimony has a long history. Before the early 1970s, children younger than eight years old rarely testified, because they failed the court's competency requirements. Then in the 1970s, when statistics showed an increase in the number of child abuse cases, courts were forced to allow the testimony of young victims, only to reemphasize adult testimony in the 1990s, when some children's testimonies were proven to be unreliable.
"Courts give witnesses instructions to tell the truth and nothing but the truth," says Brainerd. "This assumes witnesses will either be truthful or lie, but there is a third possibility now being recognized—false memories."
According to Brainerd, "Things are about to change radically."
Fuzzy Trace Theory
Traditional theories of memory assume a person's memories are based on event reconstruction, especially after delays of a few days, weeks, or months. However, Reyna and Brainerd's Fuzzy Trace Theory hypothesizes that people store two types of experience records or memories: verbatim traces and gist traces.
Verbatim traces are memories of what actually happened. Gist traces are based on a person's understanding of what happened, or what the event meant to him or her. Gist traces stimulate false memories because they store impressions of what an event meant, which can be inconsistent with what actually happened.
False memories can be identified when witnesses accurately describe what they remember but those memories are proven false based on other unimpeachable facts.
"When gist traces are especially strong, they can produce phantom recollections—that is, illusory, vivid recollections of things that did not happen, such as remembering a robber brandished a weapon and made threatening statements," says Reyna.
Brainerd says that because witness testimony is the primary evidence in criminal prosecutions, false memories are a dominant reason for convictions of innocent people.
Recently, in Cook County, Ill., more than 200 murder confessions were identified as being based on adult's false memory reports because they conflicted with unimpeachable facts. A person may have falsely remembered being in one location, for example, but a sales receipt showed he was in another location at the same time a crime was committed.