I cannot prove it scientifically because till date it hasn't been.
However I can explain you with Freud's psychoanalytical theory(proved and tested).
Mind or psyche has 3 psychic apparatus id, ego and super ego. id acts according to the "pleasure principle", seeking to avoid pain or unpleasure aroused by increases in instinctual tension. The mind of a newborn child is regarded as completely "id-ridden" in the sense that it is a mass of instinctive drives and impulses, and needs immediate satisfaction. Part of id eventually develops into structured ego.
The theme of "belief" is directly addressed by Sigmund Freud in a note accompanying a letter to Wilhelm Fliess dated May 31, 1897. Belief is described as a phenomenon belonging entirely to the ego system (consciousness), without any unconscious equivalent
Now I and you very well know that I love my mother since I was a child. According to the theory, this certainly cannot be belief because I was id-ridden when i was a child. I think I have proved my point. If you still don't understand this i will urge you to read psychoanalytical theory.
If you challenge Freud I would just call you adamant :-)