 With the Apostolic constitution Sedis <unk> , Pius XII added social sciences , sociology , psychology and social psychology , to the pastoral training of future priests . Pius XII emphasised the need to systematically analyze the psychological condition of candidates to the priesthood to ensure that they are capable of a life of celibacy and service . Pius XII added one year to the theological formation of future priests . He included a " pastoral year " , an introduction into the practice of parish work . 
