By the age of 3-4 years children understand the meaning of stealing something physical. It will still take about two years to understand the concept of stealing an idea. Five or six-year old children who are learning to write are not bothered by someone their age who copies on a sheet of paper the letters of the alphabet, but they are disturbed by someone who copies a drawing unless its ‘owner’ authorizes the copying. They are also critical of someone who copies the drawing, not for themselves, but to pass it onto a third person. These observations are similar in various cultures (US, China, Mexico) suggesting that opinions concerning intellectual and material property have a psychological basis rather that a cultural one. By the age of 5-6 years children understand that a good idea has a value and that copying it deprives the owner of the due recognition.