Charles Darwin thought that the human tendency to cry had no obvious evolving purpose He was almost certainly wrong More recently scientists have pointed to its social significance with psychiatrist John Bowlby highlighting the role of crying in developing the attachment between mother and child Many believe that tears at least during childhood are mainly an expression of helplessness However the persistence of crying into adulthood is harder to explain It seems that the sound of crying becomes considerably less important than the visual signal it conveys It may have been advantageous to early human communities as a means of promoting trust and social connectedness 