According to the American Psychological Association (APA) the median annual salary for developmental psychologists employed at universities ranges between $70,000 and $90,000 a year. Developmental psychologists working in the private sector and as research administrators can earn over $110,000 a year.sychologists in the army are entitled to special pay in addition to their base salary. Special pay typically ranges from $2,000 to $5,000 a year. Army psychologists receive allowances for health care, child care, housing and food which can equal over $30,000 a year.