THE LOCALIZATION OF SOUND IN THE WHITE RAT 



ALDA GRACE BARBER 

 From tne Psychological Laboratory oj the University oj Texas 



INTRODUCTION 



The experiments presented in the following paper are intended 

 as a preliminary study of the white rat's ability to localize 

 sound. Meyer, Johnson, and Szymanski have also made pre- 

 liminary studies, of less extent, however, upon other animals. 



Meyer's 1 problem was to investigate (1) when and how local- 

 ization appears in mammals and (2) the date of the appearance 

 of the ability to localize correctly. As a result of his work he 

 concludes that ability to localize depends upon: (1) mediate 

 factors of vision, tactual sensations, habit and experience; (2) 

 the immediate factor of hearing. Furthermore, he says true 

 localization of the second type (hearing) is a function of binaural 

 hearing, and mentions the factor of intensity. To test the 

 above problems, he used humans and various species of animals: 

 47 human nurslings, 16 older children and 100 animals, 9 of 

 which were less than a year old. With children he found that 

 the difference between location of familiar and unfamiliar sounds 

 seemed to be the essential factor. Six stages in the evolution 

 of hearing were distinguishable in the human nurslings, com- 

 parable to the stages in the animals tested. The nurslings 

 localized sounds as early as 7 weeks, although there was con- 

 siderable variation. By the end of 6 months, however, prac- 

 tically all of them localized calls and noises. His work with 

 animals falls into the following groups, a whistle furnishing 

 the stimulus: (1) 2 dogs (5 days old) gave no reaction; (2) 1 

 Samali sheep (8 mo. old), 2 bears (6 mo.), attempted to localize 

 sound but could not; (3) jaguar (5 mo.), elephant (5 mo.), 

 leopard (13 mo.), panther-leopard, localized quickly and 



1 Meyer, Julius. Die Benutzung der Schalllokalisation zum Nachweis von 

 Hordiff erenzen ; ihre Verwertung als Simulations-probe. Monat. j. Ohrenhk., bd. 

 46, S. 1-15. 1912. 



— — Weitere Beitrage zur Frage der Schalllokalisation. 



Untersuchungen an Siiuglingen und Tieren. Monat. j. Ohrenhk., bd. 46, S. 449- 

 474. 1912. 



292 



