276 JOHN D. DODSON 



2. With a discrimination problem of the difficultness used in 

 this experiment the rate of learning increases as the strength of 

 stimulus increases from the threshold up to about seventy-five 

 units, which is a comparatively weak stimulus, and gradually 

 decreases as the strength of stimulus is increased beyond this 

 point. 



3. The electric shock is more favorable to the learning process 

 in the white rat than is hunger in case of a simple discrimination 

 problem. 



4. The important factors in accounting for the differences in 

 rate of learning in this experiment are: vigor of performance, 

 frequency of repetition, native tendency with which the process is 

 linked, and the disintegration due to interfering tendencies. 



5. The time taken for forming a habit has but little to do 

 with its retention but the tendency with which it is linked may 

 be of considerable importance. 



REFERENCES 



(1) CARLSON, J. A.: The control of hunger in health and disease. 1916, Univ. 



Chicago Press. 



(2) COLE, L. W. The relation of strength of stimulus to rate of learning in the 



chick. Journal of Animal Behavior, 1911, i, 111-124. 



(3) HAGGERTY, M. E. The laws of learning. Psychol. Rev., 1912, xx, 411-422. 



(4) HOGUE, MILDRED AND STOCKING, RUTH. A note on the relative values of 



punishment and reward as motives. Journal of Animal Behavior, 

 1912, ii, 43-50. 



(5) HOLMES, S. J. Studies in animal behavior. Boston, 1916, R. G. Badger. 



(6) MARTIN, E. G. A quantitative study of faradic stimulation. Amer. 



Jour, of Physiol., xxii. 



(7) PETERSON, J. Completeness 6f response as an explanatory principle in 



learning. Psychological Rev., 1915, xxiii. 



(8) THORNDIKE, E. L. Educational psychology, briefer course. Teachers 



College, N. Y. 



(9) WASHBURN, MARGARET F. The animal mind. 2d Edit., N. Y. 1917. 



Macrnillan Co. 



(10) WATSON, J. B. Behavior an introduction to comparative psychology. 



New York, 1914, Henry Holt & Co. 



(11) YERKES, R. M. The dancing mouse. New York, 1907, Henry Holt & 



Co. 



(12) YERKES, R. M., AND DODSON, J. D The relation of strength of stimulus 



to rapidity of habit formation. The Journal of Comparative Neu- 

 rology and Psychology, 1908, xviii, 457-491. 



