Childhood amnesia kicks in around age 7
I have distinct memories of when I was 2-3 y.o. that have astounded my parents.  I was raised in Korea till I was about 3, then we all flew to Hawaii to immigrate to the U.S.  I remember the flight, I remember my life in Korea, I remember going to the public spa's with my dad, I remember feeling ashamed of my nudity in front of many older folks around me.  I told all of this to my parents later in life, and they were amazed.  I even distinctly remember the time when I thought I was lost, being scared, walking through a tunnel only to emerge to find a statue of some Korean soldiers.  My parents found me and took a picture of me pointing at that statue.  I asked my mom about that time, and I said, "How did I get lost?  I was scared."  My mom said that they were following me from afar, making sure I didn't see them, and they wanted to see how I would explore the world.I've told people about this many times.  And, people just can't or won't believe me.  A history professor told me that this is impossible, because children can't remember anything before the age of 3.  He was adamant about it, and completely dismissive of my claims.  I think these kinds of pseudo-scientific research (you know, taking polls and applying statistics) should be taken with a grain of salt.  One should NOT draw definitive conclusions from them.