operant vs persistent

operant

adj
  • That operates to produce an effect. 

noun
  • Any of a class of behaviors that produce consequences by operating (i.e., acting) upon the environment. 

  • An operative person or thing. 

persistent

adj
  • Describing a fractal process that has a positive Brown function 

  • Of data or a data structure: not transient or temporary, but remaining in existence after the termination of the program that creates it. 

  • Lasting past maturity without falling off. 

  • non-transient. 

  • Obstinately refusing to give up or let go. 

  • Insistently repetitive. 

  • Indefinitely continuous. 

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