A preference for extraversion (seeing life in terms of the external world) or introversion (greater interest in the inner world of ideas) is independ… - Tom Butler-Bowdon

We are actually programmed to get satisfaction and pleasure from discovery and creativity, he says, because its results lead to our survival as a species.

Harlow went so far as to suggest that perhaps the main function of nursing was to ensure frequent physical contact between baby and mother, since the loving bond seemed so vital for survival. After all, he noted, long after the actual sustenance stops, it is the bond that remains.

He notes that it remains the cancer of the mental health world: We are close to finding a cure, but not close enough for those who do not respond quickly to drugs or therapy.