Event Memory in Infancy and Early Childhood

A Day in the Life of a Memory

Memories are persistent traces of experience. As such, they have a beginning—a birth or origin. They also have life—a period of time during which they can be accessed, recalled, or retrieved. Most theories of why memory changes with development focus on the “covers” of the life of a memory. That is, they assume that developmental differences in how well events are remembered arise either because older children are better at originating memories (that is, at encoding experiences into memory), or that older children are better are retrieving memories from long-term storage.

We are investigating a different theory, one that focuses not on the covers of the book, but on what happens in the middle. In the middle of the book—after the experience as been encoded into a memory, but well before it is retrieved from memory storage—memory traces undergo a process of stabilization and integration into long-term storage. Collectively, the processes are known as consolidation. Importantly, the brain structures responsible for consolidation undergo a long period of development. This leads to the prediction that in infancy and early childhood, consolidation processes will not be very efficient or effective. We have been testing this prediction and whether it matters for the life of a memory.

"Make a rattle"

Put in the ball.

Cover it up.

Shake it!

To test the life of a memory, we use an imitation-based task. Infants or young children are given objects and shown how to use them to make an interesting outcome. For example, they are given two nesting cups and a block and shown that by putting the block into one cup, covering it with the other cup, and shaking the cups, they can make a “rattle” sound. Our lab has used this Elicited Imitation task to test the book-cover processes of encoding new experiences into memory and later retrieving them, as well as the middle processes of consolidating new memory traces. We test encoding by measuring immediate imitation—how well the child makes the rattle after just seeing an adult make it. We test retrieval by measuring delayed imitation—how well the child makes the rattle weeks or months after seeing an adult make it. We test the middle by measuring how well the child makes the rattle after only minutes, hours, or days have passed.

The “news” of this research is that when we measure at three points in the life of a memory—encoding, consolidation, and retrieval—the point that proves to be most important is the middle. That is, if we know how well consolidated a memory trace was minutes, hours, or days after an experience, we can pretty accurately predict how strong the memory will be weeks or months later. We now are on to the sequel of this research—we are testing whether the importance of consolidation processes changes over the course of development, as the brain structures that support it develop, and the role these processes play in autobiographical or personal memory.

You can read more about research with infants in Bauer, P. J., Güler, O. E., Starr, R. M., & Pathman, T. (2011). Equal learning does not result in equal remembering: The importance of post-encoding processes. Infancy, 16, 557-586; with preschoolers in Bauer, P. J., Larkina, M., Doydum, A. O. (2012). Explaining variance in long-term recall in 3- and 4-year-old children: The importance of post-encoding processes. Journal of Experimental Child Psychology, 113, 195-210.