August 4, 2011 -- We use our memory in every aspect of our lives, but for all that use, many people are still confused by the myths and facts behind a human's ability to recall.
In a new study published in the journal PLoS One, researchers from the University of Illinois and Union College sought to debunk the most common memory myths. Authors surveyed 1,500 people by phone to find out just how widespread some of these beliefs on memory and recollection are.
The authors, Daniel Simons, professor of psychology at University of Illinois, and Christopher Chabris, professor of college at Union College, discuss the issue of common misconceptions about memory in their book "The Invisible Gorilla." The book particularly focuses on how such false intuitions can influence judicial and political systems, along with personal relationships.
"We have strong intuitions about how attention, perception, memory and thinking work, but those intuitions can mislead us," said Simons. "For the book, we wanted to have a sense of the prevalence of some mistaken beliefs, so we decided to conduct a national survey to find out."
"The mismatch between what most people think and the established scientific record about memory speaks to the need for better science communication and to the need for expert testimony about memory and cognitive psychology in legal proceedings," continued Simons.
Before reading, test your own knowledge here.
Without further ado, here are the six highlighted memory myths that are often thought to be facts.
1. People suffering from amnesia typically cannot recall their own name or identity.
About 83 percent of people who responded to the survey agreed that "people suffering from amnesia typically cannot recall their own name and identity," but experts disagreed. The most typical form of amnesia involves the loss of ability to form and consolidate new and long-term memories. Experts say television shows and media play into the myths behind amnesia.
People suffering from memory loss usually "can remember their childhood," said Simons. "They can remember most of what they experienced before their brain damage. And they often can learn new skills that don't require them to recall what they were doing."
2. The testimony of one confident eyewitness should be enough evidence to convict a defendant of a crime.
This was the least widespread of the myths—only 37 percent of people surveyed believed that one confident observer is enough to make a decision on a person's guilt or innocence.
While the authors write that a person is more likely to be accurate when he is more confident in his memory, an expression of confidence is a limited predictor of memory accuracy. They warn that those involved with court cases must be aware that a "sizable minority of a typical jury likely misunderstands the fallibility of eyewitness testimony and may rely too heavily on confident witness statements."
One example of this comes from the 1984 conviction of Ronald Cotton, who was accused of raping Jennifer Thompson mostly because of her assured testimony, during which she confidently pointed to Cotton as the rapist. Years later, he was exonerated for his crimes after DNA testing did not match Cotton's.
"Sometimes we detect the fact that the new memory is implausible and probably not correct," said Dr. Paul Schulz, director of Memory Disorders and Dementia Clinics at University of Texas Health Science Center. "But other times, we don't know that the true memory was forgotten and replaced by a plausible memory. As a result, I think that our conviction about what we saw can be high, but our accuracy can be low."
3. Human memory works like a video camera, accurately recording the events we see and hear so that we can review and inspect them later.
While the idea sounds nice, experts say a person's memory is nothing like that of the digital device. The authors noted that the idea of memory as something that can be rewound and replayed contradicts how memory is processed through knowledge, beliefs and expectations. People encode events differently and later events can distort that memory.
"Memories help us make sense of past experiences so that we can predict future ones," said Simons. "And, each time we remember something, we effectively are reconstructing what happened."
That means that memory is less like a digital recording of a concert that sounds the same each time you play it back, and more like an improvisational performance based on a common theme, said Simons. It can differ each time it's played back, and those differences can accumulate over time.
4. Once you have experienced an event and formed a memory of it, that memory does not change.
"Memory is not a single brain process," said Schulz. "As a result, it appears that people can have an emotional memory that says, 'I'm sure about this,' that differs from what the factual memory part of our brain actually recalls. And then we have other areas that may fill in the details of what we forgot."
Much like the falsity behind the video camera, humans do not have a permanent memory recall; subsequent events and beliefs and expectations can change and re-mold a person's thoughts.
5. Hypnosis is useful in helping witnesses accurately recall details of crimes.
While several studies have shown that hypnosis can lead to more recall, that does not mean it leads to more accuracy.
"The mismatch between what most people think and the established scientific record about memory speaks to the need for better science communication and to the need for expert testimony about memory and cognitive psychology in legal proceedings," said Simons.
6. People generally notice when something unexpected enters their field of view, even when they're paying attention to something else.
While it veers off the topic of memory, in the study researchers also found that people tend to believe they will notice whenever something unexpected or important happens. While that intuitive belief is legitimate, as sometimes we do notice unexpected events, people don't realize how often we miss unexpected events.
"The problem is that we have a limited capacity for attention, and we can only focus attention on a fairly small part of our world at one time," said Simons. "When we focus attention effectively, we successfully filter out all the distractions that we don't want to see. Unfortunately, that means we also filter out some unexpected events we might want to see."