Scientists have found that some important components of memory keep developing even after the age of 7.
While some parts of memory are nearly fully developed by 4 years of age, researchers found that episodic memory - the ability to remember not only what happened, but where and when - takes longer to develop than often assumed.
That means young children may have no problem with remembering certain simple events or facts. But in some cases, they may have difficulty placing them in the right place, time or context.
"It is often assumed that most development in memory occurs by the time children have completed preschool, but we found a lot happens in memory development after 7 years of age," said Vladimir Sloutsky, co-author of the study and professor of psychology at The Ohio State University.
Sloutsky conducted the study with Hyungwook Yim, a doctoral student in psychology at Ohio State, and Simon Dennis of the University of Newcastle in Australia.
Dennis said children experience major difficulty remembering events that have overlapping elements.
The study included two experiments with 4- and 7-year-old children and adults.
In one experiment, participants were shown pictures of six pairs of objects that had to be remembered together when they were in a red house, such as a couch and a bicycle, and a dog and coffee cup.
Some of the participants were then shown that in a blue house, the same objects appeared with different pairings.
The researchers made sure that each child remembered the pairs that were found in each house, so that these simple memories were not an issue.
What the researchers really wanted to know was whether children could correctly keep track of the overlapping elements of the memories, such as that the dog was paired with the coffee cup in the red house, but the dog was paired with the couch in the blue house.
The results showed that children had great difficulty remembering the different pairings in the red house versus the blue house.
"Children had a problem when there was overlap in what they had to remember from one context to another. They didn't have the ability to create the more complex memory structures they needed," Yim said.
In the second study, the researchers had the pairs of objects associated with cartoon characters that the children would be familiar with, such as Elmo and Dora the Explorer.
This was to see if making the context more interesting and relevant to the children (compared to the houses in the first experiment) would improve their memory.
However, the results showed the children's performance did not significantly improve with the cartoon characters, rather than the houses.
The study will be published in the journal Psychological Science.
