THE ALTERNATION PROBLEM 383 



tively. 2. In the later stages of mastery, the normal rats fre- 

 quently turned immediately after entering the blocked path. 

 The blind rats did not manifest this type of behavior. When 

 wrong choices were made, the blind animals did not correct 

 their mistake until actual contact with the closed door was 

 effected. This differential behavior indicates that the normal 

 animals frequently used visual data in reacting to a blocked 



pathway. 



SUMMARY 



All rats succeeded in learning to make alternate choices be- 

 tween two exits. The problem proved to be rather difficult 

 for these animals. 



The problem is a complex one consisting of four components 

 which are stated in their order of importance. 1. The rat must 

 learn to adapt its alternate choices to the given order of pre- 

 sentation. 2. The system of making alternate choices must be 

 acquired. 3. The rat must resist the tendency of developing a 

 position preference. 4. There is the final difficulty of choosing 

 correctly in the initial trial of each day's test, — of getting the 

 day's sequence started correctly. 



These four aspects of the problem constitute to some extent 

 independent difficulties in the early stages of mastery; progress 

 in mastering one component does not necessarily depend upon 

 the animal's ability to overcome the other difficulties. The four 

 factors were mutually related in the case of some individuals, 

 but there is no necessary dependence inasmuch as they were 

 unrelated with some animals. 



Animals differ greatly in their rate of progress in mastering 

 each of these component elements of the problem. The curve 

 of learning for the problem as a whole may be regarded as a 

 combination of the four curves representing the mastery of the 

 four components. The complexity of the problem, the inde- 

 pendence of its parts, and the variability of the animals in 

 mastering each part make possible a wide range of individual 

 differences in rate and method of learning. 



The final co-ordination consists of an association between 

 each act and the sensory aspects of the preceding act as well 

 as a distinctive motor attitude resulting from the same. The 

 relative efficiency of the two stimuli in determining each choice 

 varies with the individual. The problem was mastered quickest 



