You don't remember being a baby. Our brains, as babies, are just not developed in a way that allows complex memories to form. The sensory processing portions are ticking away—sounds are processed in the auditory cortex, vision in the visual cortex, says LiveScience—but the part that puts it all together, turning sensory input in a complex memory, just isn't developed until a few years down the line.
But just because you don't remember being a baby doesn't mean baby brains don't make memories.
Over at Popular Science, Kate Gammon reports on babies' subconscious memories: in a new study, researchers found that three-and-a-half-year-old kids could remember the faces of people they'd met only once, for a short time, years prior. Shown two videos, one featuring a researcher they had met before and one featuring a stranger, the babies paid more attention to the stranger—an instance, Gammon explains, of "novelty preference," the human tendency to focus on the new.
This sort of long-term subconscious memory feels like a different thing than, say, a baby remembering a teacher, says Gammon. The one-year-old babies' interactions with the researchers were brief and fleeting—why would they have any need to remember them?
Even though the kids couldn't remember their previous encounter with the researchers, their subconscious memories still affected them. This adds an interesting moral level to how we deal with children, says one of the researchers to Gammon:
“It’s sometimes argued that if children don’t remember an instance, it couldn’t have hurt them -- which is kind of a very simple way to get around the fact children are not as good as remembering or verbalizing as adults,” he says.
But, even if kids don't know, consciously, what they've experienced, their brains still might.