It turns out that studies done on young babies, even babies in the womb, have shown that infants have got surprisingly good memory.
As reviewed by Hayne, 3-day-old infants were capable of distinguishing a particular passage (from Dr. Seuss’s “Cat in the Hat”) that had been read to them twice daily for the last 6 weeks of gestation from similar passages (matched for word count, length, and prosody).
What’s more, these infants preferred the familiar passage even if spoken by someone other than their mother, strongly suggesting that they had encoded (and retained) a relatively high-level representation of the passage’s auditory content.
Link to ‘The Myth of Infantile Amnesia’.