1502
Donald O. Hebb , in 1947 , had found that rats raised as pets performed better on problem solving tests than rats raised in cages .
 person: Donald O. Hebb
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Donald O. Hebb