altruism vs introversion

altruism

noun
  • Action or behaviour that benefits another or others at some cost to the performer. 

  • Regard for others, both natural and moral without regard for oneself; devotion to the interests of others; brotherly kindness. 

introversion

noun
  • Arrangement of two similar words, lines, etc. to form the middle part of a structure. 

  • The action of turning one's thoughts upon internal or spiritual matters. 

  • A turning inward 

  • A personality orientation towards the self and mental abstraction; behavior expressing such orientation. 

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