Multiple studies have shown us that our memories aren't entirely trustworthy. It can be difficult to distinguish a genuine recollection from a false one, but there is one class of memories you can pretty much assume is all fake: anything "remembered" before age 2. According to a new study published in Psychological Science, nearly 40 percent of people claim to remember events before this age, but their brains are almost certainly lying to them, Popular Science reports.

There's a reason you don't remember anything from when you were a baby: Your brain just wasn't wired to record information that way. Infants use their memories when they first start to walk, talk, eat, and learn in general, but that all falls into the non-declarative memory category. Declarative memory, on the other hand, describes what happens when you consciously recall things that happened to you, and it's specific to the hippocampus region of the brain.

In the first couple years of a child's life, the hippocampus is in overdrive. It's constantly growing neurons to make room for all the new information the young brain is absorbing. This is what allows babies to learn so much at such a fast rate, but it also means they have to sacrifice their long-term declarative memory. As new neurons form, old ones are pushed out, and the autobiographical memories they stored along with them.

It isn't until age 2 that this growth starts to slow down and the brain becomes capable of saving declarative memories for a longer period. But adults can still feel convinced they remember events from much earlier. When researchers asked 6641 study participants to describe their first memories and say how old they were when they happened, 2487 people reported memories from before age 2, with 893 claiming to have memories from age 1 or younger.

As these numbers suggest, it's surprisingly easy to assume the stories you tell yourself or that were told to you are accurate, first-hand recollections. Let's say you vividly remember dropping your ice cream cone at the zoo when you were 1.5 years old: What's likely happening is that you're remembering the picture that played in your head when your parents shared their own memories of the event when you were a few years older, or maybe you saw pictures taken from that day and you constructed false memories around them.

Memory doesn't become any less complicated as we enter adulthood. Even people with highly superior autobiographical memory (a real condition) are susceptible to false memories.

[h/t Popular Science]