Memories of Childhood
Children's memories are famously unreliable, as are adult's memories of the past. Memory is distorted in hundreds of ways for hundreds of reasons for which there is no space here. But there is a truly "dark age" of birth through about age 6 in which children have what Freud termed "infantile amnesia." Nothing from that period seems to be retrievable, at least not in the usual ways.
Cognitive Daily speculates, and provides an excellent thumbnail summary, on the subject of infantile amnesia here. But I'd like to add a psychoanalytic dimension to the subject, despite the Munger's discomfort with analytic theorizing - some of which is surely deserved and some of which has to do with different disciplines. The realm of "meaning" crosses many discipline boundaries, and is a strange and baffling subject.
Several points of interest:
1. Memories from birth through 6 may not be retrievable in the sense of "I remember my 4th birthday party," but emotional reactions, and states of mind - neither of which are readily expressible, may be solidly engraved in the old hippocampus - and why not? Deep memories can be visceral, not just visual and verbal.
2. People create things which psychoanalysis terms "screen memories." These are not literally accurate memories, but they are mental constructions which may capture something meaningful from the past - an issue, a conflict, a fear, a joy, a wish, etc., in a similar way in which dreams do. Thus in analysis, we tend to be more interested in the psychological meaning of memories and recollections than in their objective truth. We psychiatrists and psychoanalysts are not historians of truth, we are historians of meaning. When we have a spontaneous memory, it probably carries a telegram, from ourself to ourself, relevant to the present.
3. Memory distortion - I said I would say nothing about this, but just one superficial comment. We all re-write our histories, especially to protect ourselves from pain, or to protect our self-respect, or to create a story we can feel good about, or to portray ourselves as virtuous victims, or to justify ourselves or to rationalize things (meaning an effort to justify, or to make sense out of something we have done or thought, that we are not comfortable with), etc. etc. We do not do this consciously or willfully - our devious, self-deceiving brains do it for us. Humans are forever at battle with their consciences...those that have one.
One of the most interesting things we observe in patients in analysis is how the "narrative" of their life changes over time. Thus anyone's autobiography is a momentary story, a construction of reality, usually with a self-serving psychological purpose - and the most common is to preserve an illusion of self-regard - something which darn few of us hominid critters deserve to hold, but which we must fake to survive. There is nothing easy about being an animal with a soul. (Just ask any hunting poodle - they will tell you all about it.)