Whenever I teach about memory in my child development class at Rutgers University, I open by asking my students to recall their very first memories. Some students talk about their first day of pre-K; others talk about a time when they got hurt or upset; some cite the day their younger sibling was born.

Despite vast differences in the details, these memories do have a couple of things in common: They're all autobiographical, or memories of significant experiences in a person's life, and they typically didn't happen before the age of 2 or 3. In fact, most people can't remember events from the first few years of their lives—a phenomenon researchers have dubbed infantile amnesia. But why can't we remember the things that happened to us when we were infants? Does memory start to work only at a certain age?

Here's what researchers know about babies and memory.

Infants can form memories

Despite the fact that people can't remember much before the age of 2 or 3, research suggests that infants can form memories—just not the kinds of memories you tell about yourself. Within the first few days of life, infants can recall their own mother's face and distinguish it from the face of a stranger. A few months later, infants can demonstrate that they remember lots of familiar faces by smiling most at the ones they see most often.