THE ROLE OF VISION IN THE MENTAL LIFE OF 



THE MOUSE 



KARL T. WAUGH 



From the Harvard Psychological Laboratory 



TEN FIGURES 



CONTENTS 



I. Problems, methods and results 549 



Problem 1. Discrimination of light intensity 550 



A. Under indirect illumination 550 



Experiment (a) Black and white 552 



Experiment (b) Light and dark varieties of a color 552 



Experiment (c) Influence of background 553 



Experiment (d) Selection of yarns 555 



B. Under direct illumination 557 



Problem 2. Color discrimination 560 



A. Under indirect illumination 560 



Experiment (a) Discrimination of colored objects 560 



Experiment (b) Selection of colored yarns 564 



B. Under direct illumination 566 



Problem 3. Perception of form 570 



Problem 4. Perception of distance of object from animal 572 



Problem 5. Perception of third dimension in objects 577 



II. Binocular vision 581 



III. Kinaesl hetic sensations, the guide to movement 590 



IV. Structure of the eye of the mouse 595 



V. Summary 598 



I. PROBLEMS, METHODS AND RESULTS 



The purpose of the investigation which is described in this paper 

 was to answer the general question — What does the mouse receive 

 from the outer world through the sense of vision, and of what 

 importance in its life are the visual data so received? 



The experimental work was done in the Harvard Psychological 

 Laboratory between January, 1905, and March, 1907. I am 



THE JOURNAL OF COMPARATIVE NECROLOGY AND PSYCHOLOGY, VOL. 20, NO. 6. 



