While some people can remember what happened at an earlier age, the veracity of their memories is often questioned.
To determine at what age our earliest memories occur, the researchers at the University of Otago (in New Zealand) looked at about 50 children and their parents.
The children played a unique game when they were 2- to 4-year-olds. In the game, children placed a large object in a hole at the top of a machine and turned a handle on the side. When a bell rang, a small but otherwise identical object was delivered through a door at the bottom of the machine.
Six years later, the researchers interviewed the children and their parents to determine how well they remembered playing the game. Only about a fifth of the children recalled the event, including two children who were under 3 years old when they played the game.
About half of the parents remembered the event. Parents and children who recalled the event provided very similar reports about the game.
Although the researchers could not predict children's long-term recall on the basis of the youngsters' general memory and language skills, they found evidence that talking about the event soon after it occurred may have helped preserve it in the memories of those who remembered it.
"Our results are consistent with theories that suggest that basic capacity for remembering our own experiences may be in place by 2 years of age," said Fiona Jack, postdoctoral fellow at the University of Otago, who led the study.
"The study has implications in clinical and legal settings, where it is often important to know how likely it is that a particular memory of an early experience is in fact genuine," Jack added.
The study has been published in the journal Child Development.