moderation vs softening

moderation

noun
  • The state or quality of being moderate; avoidance of extremes 

  • An instance of moderating: bringing something away from extremes, especially in a beneficial way 

  • The process of moderating a discussion 

softening

noun
  • The process of becoming soft. 

  • The process of making something soft. 

How often have the words moderation and softening occurred in a corpus of books? (source: Google Ngram Viewer )