53891
In the late 19th century , psychologists familiar with the evolutionary theory of Darwin began seeking an evolutionary description of psychological development ; The superego plays the critical and moralizing role ; and the ego is the organized , realistic part that mediates between the desires of the id and the superego .
 Darwin
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 Darwin