Other-regarding preferences, hence appreciation of others' welfare, are mainly culturally transmitted, whereby most of the development takes place in the sensitive period of childhood and adolescence. This work analyzes the development as well as possible influencing factors of other-regarding preferences during this period. To test the hypotheses derived from developmental and socialization aspects, the author conducts a survey measuring altruistic and cooperative preferences for German pupils. Results show that over the age span studied altruism and cooperation are increasingly important. Individual differences show none or only small relationship with measures of other-regarding preferences while differences in school environments are similarly important to age differences.