JOURNAL OF ANIMAL BEHAVIOR 



Vol. 3 MARCH-APRIL 1913. No. 2. 



SIZE AND FORM PERCEPTION IN 



GALLUS DOMESTICUS 



HAROLD C. BINGHAM 



Ellsworth College 



From the Harvard Psychological Laboratory 



Four figures 

 CONTENTS 



PAGE 



I. Apparatus 65 



i. Experiment box 68 



2. Source box 71 



j. Stimulus shifter 71 



4. Accessories 73 



II. Problem, Method, and Technique 76 



1. The chicks 76 



2. The problem 77 



j. Method ami technique 79 



4. Importance of method 86 



III. Size Perception 90 



1. Discrimination between unequal circles 90 



2. Technique in experiments on size 97 



IV. Form Perception 99 



1. Literature 99 



2. Experiments 102 



V. Relative Values of Size, Form, and Brightness 110 



VI. General Idea Ill 



VII. Summary 113 



I. APPARATUS 



A frequent defect appearing in past experiments on visual 

 acuity in animals is the inadequate description of methods. 

 In many cases the conditions have been such that they could 

 not be accurately described. Complexities have been involved 

 making it impossible to ascertain with certainty the visual 

 factors on which the animals have relied in their discrimina- 

 tions. The apparatus used in the observations which are re- 

 ported in this paper was devised for the purpose of overcoming 

 this difficulty. Controllability was the primary aim in its 

 construction. 



