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In 1980 , a study by Torey Hayden identified what she called four " subtypes " of elective mutism ( as it was called then ) , although this set of subtypes is not in current diagnostic use .
 Torey Hayden
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:
 Torey Hayden