The U.S. legal system gives preference to adult testimony in child abuse cases. Cornell professors Valerie Reyna and Chuck Brainerd believe this is a mistake. Like other researchers, they have found that children's short-term memory can be more accurate than adults'. The reason for this is not that children have better functional memory capacities but that their short-term memory system works according to a different set of principles, the scientists say.
Two Kinds of Short-Term Memory
Short-term memory refers to one of two abilities: the ability to hold information in your head for up to a few minutes, or the ability to remember detailed facts, events or scenes for minutes, hours or days. The former type of short-term memory is also sometimes called "working memory" or "functional short-term memory." The two kinds of memory involve different brain structures, reports a research team in the November 9, 2009 issue of "PNAS". Working memory involves frontal brain areas and storage-based short-term memory involves the hippocampus, an area of the brain that is also crucially involved in long-term memory.
Fetal Short-Term Memory
While there are no hard data on the onset of short-term memory, a study published in the July, 2009 issue of "Child Development" shows that 30-week-old fetuses can retain information for up to ten minutes. The team used a method known as "habituation," which consists of repeating a stimulus until the brain regards it as "safe" and stops responding to it. The scientists found that when they had habituated the fetal brains in one session, habituation in a second session could be achieved with significantly fewer repetitions. This strongly indicates short-term memory, report the scientists. The team also tested 34-week-old fetuses and found that they had a memory of four weeks.
The Transient Nature of Memory in Children
Very young children do not store information in a way that will allow them to gain cognitive access to it later, report psychology professors Wolfgang Schneider and Michael Pressley in their book "Memory Development between Two and Twenty". They attribute the transient nature of young children's memories to a lack of the ability to categorize and interpret. An ability to interpret the meaning of an event or scene helps to retain memories for the long term. Since young children are unable to fully interpret their sense impressions, their memories will tend to be short-lived.
Short-Term Memory and Visual Images
Children's ability to use visual images in memory exercises is tied to the capacity of their functional short-term memory, report Schneider and Pressley. Visual images are picture-like memories of people, scenes or events. A study done by Pressley and colleagues in 1979 showed that the more information a child could hold in her head at any one time, the better she performed on image-based memory tasks. Schneider and Pressley take this to indicate that working memory problems in children can limit their ability to generate visual images. This, in turn, can affect their short-term storage capacities.
Accuracy of Children's Short-Term Memory
While children do not have the same long-term or interpretive memory capacities as adults, their short-term memory can be better, report Ohio State researchers in the August, 2004 issue of "Psychological Science." Adults process stimuli for short-term storage by sorting into abstract categories, whereas children process stimuli on the basis of resemblance. The latter requires paying more attention to details. In their book "The Science of False Memory" from 2005, Reyna and Brainerd argue for a similar conclusion. Adults who are asked to recall memories fill in the details. Children record what actually happened, so they are less likely to produce false memories, the researchers say.
References
- Science Daily: Children's Memory May Be More Reliable Than Adults' In Court Cases
- Science Daily: Theory About Long and Short-Term Memory Challenged by New Research
- Science Daily: Fetal Short-Term Memory Found In 30-Week-Old Fetuses
- "Memory Development between Two and Twenty"; Schneider and Pressley; 1997
- Science Daily: Children Can Have A Better Memory Than Adults (At Least Sometimes)
