" " Some people believe that certain automatic gestures — like scratching our heads when we're thinking — are natural motions that were passed down to us from our caveman predecessors. Jose Luis Pelaez Inc./Getty ImagesIf you've ever had the distinct pleasure of sourcing stock photos for any reason, you've likely come across a whole lot of laughing women eating salads alone. But you've also probably stumbled upon a truckload of people scratching their heads to symbolize confusion, deep thought and/or perhaps a bad case of seborrheic dermatitis — dandruff. Scalp dryness aside, how exactly did the head scratch come to symbolize intellectual processes? So instead we deflect attention from the movement and scratch or rub our head or chin or neck."