Tendency to accept deeper explanations: Unless there is some deeper explanation forthcoming, the human mind is riddled with agonizing perplexities that tend to embitter a person’s general outlook on life and foster a callous cynicism. This in many ways is even worse than the deepest personal sorrow that death may cause. But in spite of all appearances to the contrary, the human mind has in it an inborn tendency to try to restore to itself a deep and unshakable faith in the intrinsic sanity and value of life. Except where artificial resistances are created, it finds acceptable those explanations that are in conformity with this deeper law of the spirit.
Effect of getting a new brain: Those who have direct access to the truth of reincarnation are even fewer than those who have direct access to the truth of the immortality of the individual soul. The memories of all past lives are stored and preserved in the mental body of the individual soul, but they are not accessible to the consciousness of ordinary persons because a veil is drawn over them. When the soul changes its physical body, it gets a new brain; and its normal waking consciousness functions in close association with the brain processes. Under ordinary circumstances, only the memories of the present life can appear in consciousness because the new brain acts as a hindrance to the release of the memories of those experiences that had been gathered through the medium of other brains in past lives.
-Discourses 7th Ed, p314