John B. Watson
His slogan was not more babies but better brought up babies. Watson argued for the nurture side of the nature-nurture debate, claiming that the world would benefit from extinguishing pregnancies for twenty years while enough data was gathered to ensure an efficient child-rearing process.  Watsons’ description of a happy child was rather detached. It included ideas such as that the child can occupy himself through his problem-solving abilities, should only cry when in physical pain, and that the child stray from asking questions. Behavior analysis of child development as a field may have begun with the writings of Watson.