Why is it that we can't recall our early years as babies?

You watch the joyful crowd around you, eye the chocolate cake placed in front of you, and then, just as everyone begins singing "Happy Birthday," you instinctively do what comes naturally: smash the cake with both hands.

This would seem strange, except for the fact that you're in a highchair. Which would be even stranger, except for the fact that you're turning 1.

Chances are, you don't remember your first or second birthday party -- or many other events from your early childhood -- and you're not alone. Forgetting those early memories is normal, even though those experiences are some of the most formative and important of your life.

It's difficult for most adults to remember their earliest experiences unless they are reminded by others who frequently recount those moments, or the memories are stirred up by photos or other triggers.

This is known as childhood amnesia. You might have been able to vividly remember and talk about your second birthday party for months after it happened, but a year later, those memories may begin to fade and eventually disappear entirely.

Experts suggest that the rapid turnover of memories from childhood may be a key reason for this, as the constant influx of new experiences forces some earlier memories to be forgotten.

In one study, children up to the age of 3 were able to recall important events from the previous year. The ability to remember such events remained high until they were 7, with participants remembering up to 72 percent of the same experiences they had recalled at 3. However, by ages 8 or 9, most could only remember about 35 percent of the events they had described so clearly as 3-year-olds [source: Gray].

Researchers concluded that this shift occurs because of how memories are formed as children grow older. Starting at age 7, children begin to organize memories more linearly, placing them into a structured sense of time and space. This process of organizing and recalling memories may lead to retrieval-induced forgetting, a phenomenon where older children and adults inadvertently forget their earliest memories while focusing on more recent events [source: Gray].

Babies Form Memories Differently

To grasp why we can’t recall being wrapped up as infants, or much else from our early years, we must first understand how our first experiences are imprinted on our brains.

Infants rely on both semantic and episodic memory. Semantic memory involves processing information not based on personal experience (such as the names of colors or historical dates). Episodic memory is tied to personal experiences (like remembering the first day of school or where you were on 9/11). Over time, episodic memories can become semantic, so that you no longer recall learning about dogs by playing with your first pet, you just know what a dog is [source: Zimmermann].

Researchers believe our inability to remember early childhood events might be due to how memories are stored and retrieved. While both semantic and episodic memories are housed in different areas of the brain's cortex, it's only between the ages of 2 and 4 that the brain's hippocampus connects these various regions into a unified network, enabling long-term memory retrieval for both children and adults [source: Shouse].

Does this insight into early childhood memory formation truly explain our inability to remember our baby years? A 2014 study suggests that it's the brain's circuits that hinder our ability to recall babyhood memories.

New findings published in the journal Science have provided fresh insight into why older children and adults forget their earliest years. The study focused on the continuous creation of new cells in the brains of infants. This process, known as neurogenesis, occurs throughout a mammal’s life, but babies produce new neurons at an exceptionally fast pace. And where does this production happen? The hippocampus, which is essential for accessing the memories we accumulate [source: Locke].

In an experiment with rodents, researchers hypothesized that the surge of new neurons in the hippocampus interferes with the formation and retrieval of memories. Indeed, when drugs were used to reduce the creation of new neurons in the rodents, they showed better memory recall. Conversely, increasing the number of new neurons had the opposite effect [source: Locke].

Tapping Into Early Childhood Memories

Despite extensive research on early childhood, there are still no clear answers as to when exactly we start losing memories of our babyhood. Among your friends, you may find some who can recall childhood moments more vividly and from an earlier age than others.

One fascinating theory suggests that the ability to remember being a baby might be linked to whether someone is left- or right-handed. A study published in the journal Neuropsychology proposed that individuals who use both hands for tasks (mixed-handed) may retain childhood memories from an earlier age compared to those who are exclusively right-handed [source: Winerman].

In this study, approximately 100 college students who were either ambidextrous or right-handed were asked to write down two early childhood memories. One memory had to be something they personally recalled, and the other should be a memory told to them by a parent or another witness, later confirmed as true. The exercise aimed to assess both semantic and episodic memory. The results showed that mixed-handers were able to remember their own (episodic) memories from an earlier age than right-handers. They also retold memories shared with them from a younger age. The researchers speculate that this could be due to more communication between the brain's hemispheres in mixed-handers [source: Winerman].

The corpus callosum, a nerve bundle connecting the two brain hemispheres, starts functioning around ages 4 or 5. At this same age, childhood amnesia tends to fade as episodic memories begin to be stored in the left hemisphere of the brain and accessed from the right. (Semantic memories are both stored and accessed in the left hemisphere.) The study suggests that better communication between the right and left hemispheres might enable mixed-handers to encode and retrieve early memories more effectively than right-handers, and they might even have a thicker corpus callosum [source: Winerman].