Theory in practice: with all my respect to Mr. J.B. Watson for his contribution to the theory of behaviorism, I need to reveal that his strict, learning-theory based non-affectionate child rearing practice ended up with deeply injured children. Two of them committed suicide, and a third one struggled with his physical and mental health until his early death. You can read about it from first hand in the following book: Mariette Hartley: Breaking the Silence
Learning theory is valuable and working, but it is only a piece of reality. We cannot restrict ourselves and our child rearing practices to such a narrow attention path which concentrates only the immediately observable behavior of a child. There is so much more in the background that needs to be considered: the early experiences and the type of the attachment, building up trust, teaching communication, supporting cooperation, emotion regulation just to name a few.
Seeing the cultural history of humankind and the different approaches of the psychology itself, the secure bonding, closeness seeking, the long nursing way of child rearing is far more conventional then fallowing the methods of a last century intentionally narrowed scientific approach. Moreover: more and more data suggest that it is much healthier than the last century affection-denying style.