Trauma Resets Personality
Such change is theoretically possible but it would require profound changes in brain biology. For instance, researchers shifted polygynous mountain voles to monogamy by altering brain receptors for the hormone oxytocin (2).
Deep means hard to change – not hard to acquire
A trait does not have to be genetically inherited, or even present at birth, to be deep. If you ever felt nauseated by eating porridge as a child, the chances are that you skip the oatmeal when you go out for breakfast decades later. Food aversions are deep, but they can form after a single unpleasant meal, according to experiments on rats.
Picture, thanks to ~Remembering Loved Ones