Accounts of people who in therapy, usually in their 30 s suddenly recover memories of childhood abuse. E.g., sexual abuse, watching a parent murder another child etc. This is evidence that some people who were abused as children do not remember. Later falsely recognize the word sweet - found somewhat different activation of brain for false recognition. However this result does not really scale up to traumatic events from childhood.
Psychologists agree that both phenomena exist.
At this point is impossible to distinguish a true memory from a false one.