A seven-month-old baby witnessed her parents' murder in Mexico. Can a baby remember a horrific event like a 10-year-old who might recall the horrific sight and sound, in graphic detail? Yes and no, Slate explains.
You can't create conscious memories until you're about two years old, but babies do respond to to traumatic events - deafening sounds, stress in people around them - with their own stress reactions, and dead bodies freak them out even if they don't understand the concept of death exactly. Also, according to some theories, they might have an implicit memory, where a baby who sees somebody stabbed to death with a knife might get agitated when they see a knife months later. There might be mid-term psychological effects, too, like being more violent playing with toys months later, or less outwardly emotional.
So it's possible a baby Bruce Wayne might still have become Batman. Say, if his parents had left the theatre because he was crying as an infant, even though he wouldn't remember exactly what happened, he might still have developed the same sense of guilt, and still be plagued by many of the same requisite psychological issues that led him to become Batman.
In other words, memories don't have to be etched into our brains in precise detail in order to haunt us, even the faintest impressions they leave behind might be more we wish. [Slate]