manipulate vs pull strings

manipulate

verb
  • To influence or control someone in order to achieve a specific purpose, especially one that is unknown to the one being manipulated and beneficial to the manipulator; to use 

  • To move, arrange or operate something using the hands 

  • To handle and move a body part, either as an examination or for a therapeutic purpose 

  • To influence, manage, direct, control or tamper with something 

pull strings

verb
  • To manipulate a situation, especially by asking favours of others; to use one's influence with others to attain a desired goal. 

  • To control a person, organization, or situation by operating behind the scenes, as a puppeteer controls a marionette. 

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