piloerection vs pilomotor reflex

piloerection

noun
  • The erection of hairs or papillae 

  • goose bumps; goose pimples 

pilomotor reflex

noun
  • Raised skin, usually caused by the involuntary erection of hairs on the neck or arms caused by cold, excitement, or fear. 

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