By very virtue of being human, everyone has experienced infancy and toddlerhood. So why can most adults not remember anything that happened before the age of 3?
Research has suggested that's because infants don't have the neural capabilities needed to retain an autobiographical memory. And now, a new study shows we start forgetting our earliest memories around age 7, a phenomenon coined by Sigmund Freud called "childhood amnesia."
Researchers from Emory University noted that their study differs from past studies on childhood amnesia because those involved interviewing adults about their earliest memories. But the new study, published in the journal Memory, involved interviewing young children.
"We actually recorded the memories of children, and then we followed them into the future to track when they forgot these memories," study researcher Patricia Bauer, a psychologist at the university, explained in a statement.
Eighty-three children participated in the study, starting at age 3. Researchers had the children's mothers and fathers ask them about six different events -- like a zoo trip or birthday -- that occurred in the last six months, with language such as "Remember when we went to Chuck E. Cheese’s for your birthday party?" Researchers found that when parents let their children take the "lead" in describing details about the events, the children were able to recall richer memories.
Then, researchers split the children up into five groups, and followed up with each group when they reached age 5, 6, 7, 8 or 9.
Researchers found that the kids followed up with at ages 5, 6 and 7 were able to recall 63 to 72 percent of the events they had been interviewed about at age 3.
Meanwhile, the kids followed up with at ages 8 or 9 were only able to recall 35 percent of the events they had been interviewed about previously. However, researchers noted that even though the 5-to-7-year-olds were able to remember more, their "narratives of these events were less complete," Bauer said. "The older children remembered fewer events, but the ones they remembered had more detail."